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Diagnostic CriteriaPEM-relevant

Diagnostics

497 studies in the atlas

ME/CFS diagnosis has historically been complicated by inconsistent and sometimes conflicting case definitions. The Fukuda 1994 criteria, Oxford criteria, Canadian Consensus Criteria (CCC), International Consensus Criteria (ICC), and IOM/SEID 2015 criteria differ substantially in their requirements — particularly regarding post-exertional malaise, which is required by CCC, ICC, and IOM but not by Fukuda or Oxford. Research increasingly demonstrates that case definition quality shapes research findings, with studies using strict PEM-required criteria identifying a more homogeneous patient population and stronger biomedical findings. The atlas classifies each study by the case definition used.

What we know

  • Diagnosis is currently based on clinical criteria, primarily CCC (2003), ICC (2011), and IOM/NAM (2015)
  • All modern criteria require PEM as a cardinal feature
  • Two-day CPET provides objective evidence of exercise intolerance but is not widely available
  • Average time to diagnosis exceeds 5 years in many countries, with high rates of initial misdiagnosis

What remains uncertain

  • Several blood-based biomarker candidates are under investigation but none is clinically validated
  • Whether AI-assisted diagnostic tools could improve recognition in primary care
  • The optimal screening approach for identifying ME/CFS in post-infectious populations
  • Whether the IOM criteria perform differently from CCC in clinical versus research settings

What is emerging

  • When a clinically validated diagnostic biomarker will become available
  • Whether composite biomarker panels will outperform single markers
  • How to reduce diagnostic delay without sacrificing diagnostic accuracy
  • Whether wearable data (heart rate, activity) could support earlier recognition

Start here

E0 ConsensusPEM requiredHigher confidence

Myalgic encephalomyelitis (or encephalopathy)/chronic fatigue syndrome: diagnosis and management

NICE Guideline Committee·National Institute for Health and Care Excellence (NICE)·2021

The UK's National Institute for Health and Care Excellence updated its ME/CFS guidelines after a comprehensive evidence review. The updated guidelines removed Graded Exercise Therapy (GET) and Cognitive Behavioural Therapy (CBT) as recommended treatments, as evidence showed they were not effective and could be harmful. Pacing and energy management were endorsed.

Research Momentum

497 publications over 46 years. Recent trend: decreasing (12/year over the last 3 years).

All Studies

497 studies, sorted by review status and evidence level

E0 ConsensusPEM unclearModerate confidenceGuidelineEditor reviewed

[Interdisciplinary consensus statement about the diagnosis and treatment of chronic fatigue syndrome/myalgic encephalomyelopathy].

Simonyi, Gábor, Bedros, J Róbert, Réthelyi, János et al.·Orvosi hetilap·2025

This paper is a consensus statement from multiple medical experts that reviews what is currently known about ME/CFS, including its varied symptoms affecting the body, thinking, mood, and daily functioning. The authors recognize that ME/CFS is increasingly common but still not well understood or acknowledged in Hungarian medicine, so they compiled international guidelines and treatment suggestions to help healthcare providers better care for patients with this condition.

Diagnostics
E0 ConsensusPEM unclearHigher confidenceSystematic-ReviewEditor reviewed

Systematic review of fatigue severity in ME/CFS patients: insights from randomized controlled trials.

Park, Jae-Woong, Park, Byung-Jin, Lee, Jin-Seok et al.·Journal of translational medicine·2024

This study looked at 60 previous clinical trials involving over 7,000 ME/CFS patients to understand how severe their fatigue really is. Researchers converted all the different fatigue measurements used in these trials into a common scale (0-100) so they could compare results. They found that ME/CFS patients experience very high fatigue levels (around 78 out of 100), affecting their thinking, physical abilities, and mood in different ways.

Diagnostics
E0 ConsensusPEM unclearHigher confidenceEditor reviewed

NICE guideline on ME/CFS: robust advice based on a thorough review of the evidence.

Barry, Peter Walter, Kelley, Kate, Tan, Toni et al.·Journal of neurology, neurosurgery, and psychiatry·2024

In 2021, NICE (the UK's health guideline organization) published official recommendations for diagnosing and treating ME/CFS based on careful review of available research. When critics raised concerns about how the evidence was interpreted, the guideline authors explained that these criticisms were based on misunderstandings of how the guideline process works. This paper defends the guideline as a balanced and thoughtful approach to managing this serious condition.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceEvidence-MapEditor reviewed

Healthcare system barriers impacting the care of Canadians with myalgic encephalomyelitis: A scoping review.

Hussein, Said, Eiriksson, Lauren, MacQuarrie, Maureen et al.·Journal of evaluation in clinical practice·2024

This study looked at all available Canadian research to understand why people with ME/CFS struggle to get good healthcare. The researchers found that the main problems are: doctors often don't believe ME is real, healthcare providers aren't trained to recognize it, there's a lack of good information about the disease, and sexism plays a role. The study suggests that improving doctor education and creating better care systems could help ME patients get the support they need.

Diagnostics
E0 ConsensusPEM not requiredPreliminarySystematic-ReviewEditor reviewed

The role of psychiatry in diagnosis and treatment of paediatric chronic fatigue syndrome - a scoping literature review.

Dolp, Reinhard, Wardle, David Pr, Khalid-Khan, Sarosh·International journal of adolescent medicine and health·2023

This review looked at how psychiatry (the medical specialty focused on mental health) is involved in diagnosing and treating ME/CFS in children and teenagers. The researchers searched medical literature and found that psychiatrists are rarely part of the care team for young people with ME/CFS, and when they are involved, their role is often unclear or limited to treating separate mental health problems. The study suggests that psychiatry could potentially play a more defined and helpful role in caring for children and adolescents with ME/CFS.

Diagnostics
E0 ConsensusPEM requiredHigher confidenceGuidelineEditor reviewed

Myalgic encephalomyelitis (or encephalopathy)/chronic fatigue syndrome: diagnosis and management

NICE Guideline Committee·National Institute for Health and Care Excellence (NICE)·2021

The UK's National Institute for Health and Care Excellence updated its ME/CFS guidelines after a comprehensive evidence review. The updated guidelines removed Graded Exercise Therapy (GET) and Cognitive Behavioural Therapy (CBT) as recommended treatments, as evidence showed they were not effective and could be harmful. Pacing and energy management were endorsed.

InterventionsDiagnostics
E0 ConsensusPEM unclearModerate confidenceSystematic-ReviewEditor reviewed

Recovery from chronic fatigue syndrome: a systematic review-heterogeneity of definition limits study comparison.

Moore, Yasmin, Serafimova, Teona, Anderson, Nina et al.·Archives of disease in childhood·2021

This study looked at how often children with ME/CFS recover and what 'recovery' actually means. Researchers found that different studies define recovery in very different ways—some focus on returning to school, others on fatigue levels, and others on physical activity. Because of these differences, recovery rates ranged wildly from 4.5% to 83%, making it hard to compare studies fairly.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceSystematic-ReviewEditor reviewed

Systematic review and meta-analysis of the prevalence of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME).

Lim, Eun-Jin, Ahn, Yo-Chan, Jang, Eun-Su et al.·Journal of translational medicine·2020

This study looked at 45 research projects involving over 1 million people to estimate how many people have ME/CFS worldwide. The researchers found that about 0.68% of the general population (roughly 1 in 150 people) has ME/CFS, though the number varies depending on who was studied and how the diagnosis was made. Women are about 1.5 to 2 times more likely to have ME/CFS than men.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceSystematic-ReviewEditor reviewed

A Literature Review of GP Knowledge and Understanding of ME/CFS: A Report from the Socioeconomic Working Group of the European Network on ME/CFS (EUROMENE).

Pheby, Derek F H, Araja, Diana, Berkis, Uldis et al.·Medicina (Kaunas, Lithuania)·2020

This study looked at what general practitioners (GPs) know and believe about ME/CFS by reviewing 33 research papers. The researchers found that many GPs don't believe ME/CFS is a real illness or don't feel confident diagnosing it, and patients often report feeling dismissed by their doctors. This problem has been going on for decades and hasn't improved much.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceReview-NarrativeEditor reviewed

Myalgic encephalomyelitis/chronic fatigue syndrome and the biopsychosocial model: a review of patient harm and distress in the medical encounter.

Geraghty, Keith J, Blease, Charlotte·Disability and rehabilitation·2019

This review examines why many ME/CFS patients feel harmed or upset after seeing doctors. The researchers found seven main problems: difficulty getting diagnosed, being misdiagnosed with other conditions, trouble accessing medical support, poor quality of care, negative experiences with treatments like cognitive behavioral therapy and exercise programs, doctors not believing patients' descriptions of their illness, and emotional distress. The authors suggest that doctors should listen more carefully to patients and adopt approaches centered on what patients actually experience.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceReview-NarrativeEditor reviewed

How have selection bias and disease misclassification undermined the validity of myalgic encephalomyelitis/chronic fatigue syndrome studies?

Nacul, Luis, Lacerda, Eliana M, Kingdon, Caroline C et al.·Journal of health psychology·2019

This study examines why ME/CFS research has been inconsistent and controversial. The main problem is that doctors and researchers use different definitions to diagnose ME/CFS, which means different groups of patients are studied in different research projects. The authors explain how using clearer, more consistent diagnostic criteria could help researchers better understand the disease and make progress in finding treatments.

Diagnostics
E0 ConsensusPEM not requiredWeak / uncertainEditorialEditor reviewed

[Chronic Fatigue Syndrome: A Critical Review].

Rollnik, Jens D·Fortschritte der Neurologie-Psychiatrie·2017

This review examines whether ME/CFS is a distinct disease or if its symptoms overlap significantly with depression and other conditions. The authors found that while ME/CFS affects less than 1% of the population, there is no clear biological explanation for what causes it, and there are no universally agreed-upon diagnostic criteria. They recommend trying exercise, antidepressants, and talk therapy, but caution against using aggressive immune therapies without stronger evidence.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceReview-NarrativeEditor reviewed

Practical management of chronic fatigue syndrome or myalgic encephalomyelitis in childhood.

Brigden, Amberly, Loades, Maria, Abbott, Anna et al.·Archives of disease in childhood·2017

This article provides practical guidance on how doctors should diagnose and treat ME/CFS in children and teenagers. ME/CFS is a serious condition that affects at least 1 in 100 secondary school students in the UK, causing severe fatigue and limiting daily activities. Although effective treatments exist, many young people with ME/CFS don't get diagnosed or receive help they need.

Diagnostics
E0 ConsensusPEM requiredHigher confidenceGuidelineEditor reviewed

Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness

Institute of Medicine Committee on the Diagnostic Criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome·National Academies Press·2015

The US Institute of Medicine reviewed over 9,000 scientific articles to establish new diagnostic criteria for ME/CFS. The report introduced SEID (Systemic Exertion Intolerance Disease) as a proposed name and established that ME/CFS is a serious, chronic, complex systemic disease. New criteria require PEM, unrefreshing sleep, plus cognitive impairment or orthostatic intolerance.

DiagnosticsPost-Exertional Malaise
E0 ConsensusPEM requiredModerate confidenceSystematic-ReviewEditor reviewed

Diagnostic Methods for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Systematic Review for a National Institutes of Health Pathways to Prevention Workshop.

Haney, Elizabeth, Smith, M E Beth, McDonagh, Marian et al.·Annals of internal medicine·2015

This study reviewed 44 existing research papers to understand how doctors diagnose ME/CFS. Researchers found that doctors currently use nine different sets of diagnostic guidelines, and a new one was recently proposed by the Institute of Medicine. However, none of these methods have been properly tested to reliably identify ME/CFS patients in real-world situations where doctors are uncertain about the diagnosis.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceEvidence-MapEditor reviewed

National Institutes of Health Pathways to Prevention Workshop: Advancing the Research on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Green, Carmen R, Cowan, Penney, Elk, Ronit et al.·Annals of internal medicine·2015

In 2015, the National Institutes of Health organized a major workshop bringing together experts to review what scientists know about ME/CFS and identify the most important questions that still need answers. The experts reviewed existing research evidence, listened to presentations, and considered feedback from patients and the public to create a roadmap for future research studies. This effort helped the U.S. medical and research community agree on which ME/CFS research areas should receive priority and funding.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceSystematic-ReviewEditor reviewed

Case definitions for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME): a systematic review.

Brurberg, Kjetil Gundro, Fønhus, Marita Sporstøl, Larun, Lillebeth et al.·BMJ open·2014

This study reviewed 20 different definitions doctors use to diagnose ME/CFS and examined 38 research studies that tested how well these definitions work. The researchers found that while one definition (CDC-1994/Fukuda) is used most often, no single definition has been proven to be the best. The study suggests that instead of creating more new definitions, doctors should focus on using the same definitions consistently and grouping patients by symptom patterns to predict who will improve with different treatments.

Diagnostics
E0 ConsensusPEM not requiredPreliminarySystematic-ReviewEditor reviewed

[A literature review on Chinese medicine syndrome and syndrome elements of chronic fatigue syndrome].

Peng, Min, Ma, Hong-bo, Si, Guo-min·Zhongguo Zhong xi yi jie he za zhi Zhongguo Zhongxiyi jiehe zazhi = Chinese journal of integrated traditional and Western medicine·2014

This study reviewed 20 years of Chinese medicine research on ME/CFS to identify common patterns doctors observe in patients. Researchers found that ME/CFS patients typically show patterns the Chinese medicine tradition calls 'deficiency syndromes'—meaning the body's energy (qi) and vital resources are depleted—sometimes mixed with blockages or stagnation. The most common patterns involved the spleen, liver, kidneys, and heart systems.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceSystematic-ReviewEditor reviewed

Overcoming the barriers to the diagnosis and management of chronic fatigue syndrome/ME in primary care: a meta synthesis of qualitative studies.

Bayliss, Kerin, Goodall, Mark, Chisholm, Anna et al.·BMC family practice·2014

This study looked at 21 previous research articles about why many doctors struggle to diagnose and treat ME/CFS in general practice. The main problem found was that many doctors don't fully understand the condition and rely too much on traditional medical thinking that looks for single physical causes. Doctors who successfully diagnosed and managed ME/CFS patients tended to take a wider view of the illness and worked together with patients to find management strategies that worked for them.

Diagnostics
E0 ConsensusPEM requiredModerate confidenceSystematic-ReviewEditor reviewed

The adoption of chronic fatigue syndrome/myalgic encephalomyelitis case definitions to assess prevalence: a systematic review.

Johnston, Samantha, Brenu, Ekua W, Staines, Donald R et al.·Annals of epidemiology·2013

This study looked at 31 different research projects that tried to measure how many people have ME/CFS, and found that scientists were using 8 different sets of diagnostic criteria (rules for identifying the illness). The 1994 CDC criteria became the most commonly used worldwide, but the authors argue that newer, more precise diagnostic standards like the Canadian Consensus Criteria and International Consensus Criteria should be used instead to get more accurate prevalence numbers.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceMeta-AnalysisEditor reviewed

The prevalence of chronic fatigue syndrome/ myalgic encephalomyelitis: a meta-analysis.

Johnston, Samantha, Brenu, Ekua W, Staines, Donald et al.·Clinical epidemiology·2013

This study looked at 14 different research studies to understand how many people have ME/CFS. The researchers found that when people reported their own symptoms, about 3.3% said they had ME/CFS, but when doctors clinically assessed patients, only about 0.76% were diagnosed. This big difference suggests that how doctors test for and diagnose ME/CFS matters a lot.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceReview-NarrativeEditor reviewed

A review of the definitional criteria for chronic fatigue syndrome.

Christley, Yvonne, Duffy, Tim, Martin, Colin R·Journal of evaluation in clinical practice·2012

Doctors have been trying to agree on how to diagnose ME/CFS for over 30 years, but they still don't have a single agreed-upon definition. This review looked at five different official definitions that doctors use to diagnose the condition. The most commonly used definition, from the CDC in 1994, has never been proven to be better than the others and has been criticized for not being specific enough.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceReview-NarrativeEditor reviewed

Pediatric Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Jason, Leonard A, Barker, Kristen, Brown, Abigail·Reviews in health care·2012

This review examines how ME/CFS affects children and teenagers, which can be quite different from how it affects adults. The authors looked at existing research on how common pediatric ME/CFS is, how doctors diagnose it, what treatments are available, and what happens to children over time. They identified important gaps in our understanding and call for better ways to recognize and help young people with this condition.

Diagnostics
E0 ConsensusPEM not requiredPreliminaryReview-NarrativeEditor reviewed

CFS: A Review of Epidemiology and Natural History Studies.

Jason, Leonard A, Porter, Nicole, Brown, Molly et al.·Bulletin of the IACFS/ME·2009

Most ME/CFS research has only studied patients who went to doctors or hospitals, which misses people from minority communities and lower-income backgrounds who may not have access to medical care. This review looks at what we know about how common ME/CFS is, how it develops, and what factors increase the risk of getting it. The authors highlight one study that looked at ME/CFS in a diverse urban community rather than just in clinic patients, which gives a more accurate picture of the illness.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceSystematic-ReviewEditor reviewed

A systematic review of chronic fatigue syndrome: don't assume it's depression.

Griffith, James P, Zarrouf, Fahd A·Primary care companion to the Journal of clinical psychiatry·2008

This review examined how ME/CFS is different from depression, since doctors often confuse the two conditions. The researchers looked at hundreds of medical articles to understand what causes ME/CFS, how to properly diagnose it, and how to treat it. They found that ME/CFS is missed in over 80% of people who have it, and is frequently wrongly labeled as depression instead.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceSystematic-ReviewEditor reviewed

Chronic fatigue syndrome: a systematic review.

Maquet, D, Demoulin, C, Crielaard, J M·Annales de readaptation et de medecine physique : revue scientifique de la Societe francaise de reeducation fonctionnelle de readaptation et de medecine physique·2006

This review examined all available research about ME/CFS to understand what we know about the condition. Researchers found that ME/CFS affects between 0.2% and 0.7% of people and that despite decades of research into possible causes like infections, immune problems, and hormonal imbalances, we still don't fully understand what causes the illness. Treatment should combine physical rehabilitation with psychological support to address the whole person.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceReview-NarrativeEditor reviewed

Chronic fatigue syndrome: the need for subtypes.

Jason, Leonard A, Corradi, Karina, Torres-Harding, Susan et al.·Neuropsychology review·2005

ME/CFS is a complex condition that affects people in different ways, and researchers found that treating it as one single disease may not be helpful. This review shows that patients with ME/CFS have different combinations of symptoms, different levels of disability, and different biological markers (measurable signs in the body), suggesting the condition should be divided into subtypes. Just like how different patients with diabetes or heart disease need different treatment approaches, ME/CFS patients might benefit from being grouped into categories so doctors can provide more targeted care.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceEditorialEditor reviewed

Chronic fatigue and chronic fatigue syndrome: shifting boundaries and attributions.

Lloyd, A R·The American journal of medicine·1998

This review examines how fatigue is defined and diagnosed, and how different definitions lead to very different estimates of how many people have chronic fatigue syndrome. The authors look at how doctors and researchers measure fatigue using patient reports, and explore whether fatigue that follows infections is a real medical condition. The study highlights that without clear, consistent definitions, it's difficult to understand the true scope of the problem.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceReview-NarrativeEditor reviewed

Epidemiologic advances in chronic fatigue syndrome.

Levine, P H·Journal of psychiatric research·1997

This review summarized what researchers knew about ME/CFS in 1997, including how common it is, who gets it, and what affects recovery. The study found that about 200 out of every 100,000 people have ME/CFS, and that women are more likely to develop it than men. The review also noted that people with sudden-onset ME/CFS tend to recover better than those whose symptoms start gradually.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceEditorialEditor reviewed

Postviral fatigue syndrome: time for a new approach.

David, A S, Wessely, S, Pelosi, A J·British medical journal (Clinical research ed.)·1988

This 1988 review examined how ME/CFS was being studied and discussed in medical literature, finding significant problems with how research was being conducted. The authors argued that the condition should not be viewed as simply 'all in your head' or 'purely physical,' but rather as involving multiple factors affecting the body and mind. They called for better research methods and clearer definitions before doctors could effectively help patients.

Diagnostics
E0 ConsensusPEM unclearPreliminarySystematic-ReviewEditor reviewed

Use of artificial intelligence and machine learning for the management of fibromyalgia: a scoping review.

Clempi Almeida E Silva, Ana Laura, Reis, Victor Hugo Palhares Flávio, Lamoglia, Antonieta Santos Andrade et al.·The Journal of manual & manipulative therapy·2026

This review looked at 43 studies from 2011–2024 to see how artificial intelligence (AI) and machine learning can help diagnose fibromyalgia and other conditions like ME/CFS. Researchers found that AI tools can identify unique patterns in brain scans, genes, eye imaging, and blood markers that differ between sick patients and healthy people. While some AI models showed very high accuracy (up to 100%), most studies tested only small groups of patients, so we need bigger, more rigorous research before these tools can be used reliably in clinics.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceSystematic-ReviewEditor reviewed

Ignored, dismissed, and minimized: Understanding the harmful consequences of invalidation in health care-A systematic meta-synthesis of qualitative research.

Bontempo, Allyson C, Bontempo, John M, Duberstein, Paul R·Psychological bulletin·2025

This study looked at how doctors dismissing or minimizing patients' symptoms affects people with hard-to-diagnose illnesses like ME/CFS. Researchers reviewed over 150 studies involving more than 11,000 patients and found that when doctors don't believe or validate patients' experiences, it causes serious harm—including shame, anxiety about healthcare, avoidance of doctors, and delays in getting diagnosed. The study shows that invalidation by healthcare providers can actually make patients' health outcomes worse.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceGuidelineEditor reviewed

Celiac Disease-Related Conditions: Who to Test?

Zingone, Fabiana, Bai, Julio C, Cellier, Christophe et al.·Gastroenterology·2024

This review looked at which patients should be tested for celiac disease, a condition where the immune system reacts to gluten in food. The authors found that celiac disease is often missed and recommend testing in people with certain autoimmune diseases, digestive problems, thyroid disease, and other specific conditions—including chronic fatigue syndrome. They suggest blood tests first, with biopsies during endoscopy if needed to confirm the diagnosis.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceReview-NarrativeEditor reviewed

Autoimmune Autonomic Neuropathy: From Pathogenesis to Diagnosis.

Nakane, Shunya, Koike, Haruki, Hayashi, Tomohiro et al.·International journal of molecular sciences·2024

This review describes autoimmune autonomic ganglionopathy (AAG), a rare condition where the immune system attacks nerve cells that control automatic body functions like heart rate and blood pressure. The authors explain how doctors can diagnose AAG and how it differs from other similar conditions, including ME/CFS and long COVID, which can have overlapping symptoms.

Autonomic Nervous SystemDiagnostics
E0 ConsensusPEM unclearModerate confidenceEditor reviewed

Myalgic encephalomyelitis/chronic fatigue syndrome from current evidence to new diagnostic perspectives through skeletal muscle and metabolic disturbances.

Pietrangelo, Tiziana, Cagnin, Stefano, Bondi, Danilo et al.·Acta physiologica (Oxford, England)·2024

This review examines what we know about ME/CFS by focusing on problems in muscles and how the body uses energy. Researchers looked at existing research to understand why ME/CFS causes severe tiredness and muscle problems. The authors suggest that studying muscle tissue more closely might help doctors diagnose ME/CFS better and develop new treatments.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceReview-NarrativeEditor reviewed

Is chronic fatigue syndrome the same illness as fibromyalgia: evaluating the 'single syndrome' hypothesis.

Abbi, B, Natelson, B H·QJM : monthly journal of the Association of Physicians·2013

This study looked at whether ME/CFS and fibromyalgia are actually the same illness or two different conditions. Researchers reviewed published studies comparing these two syndromes and found meaningful differences between them, suggesting they are distinct illnesses rather than just variations of one condition. This finding helps doctors understand that these are separate health problems that may need different approaches to treatment.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceReview-NarrativeEditor reviewed

Chronic fatigue syndrome and fibromyalgia: clinical assessment and treatment.

Friedberg, F, Jason, L A·Journal of clinical psychology·2001

This review examines how ME/CFS and fibromyalgia are similar conditions that doctors don't fully understand yet. The authors looked at research on what causes these illnesses, how to diagnose them (including checking for depression and anxiety), and what treatments work—including medications, alternative therapies, and talking with a therapist. The study suggests that mental health professionals can play an important role in helping patients manage their symptoms.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceSystematic-ReviewEditor reviewed

A review of the evidence for overlap among unexplained clinical conditions.

Aaron, L A, Buchwald, D·Annals of internal medicine·2001

This review examined eight unexplained illnesses—including ME/CFS, fibromyalgia, and irritable bowel syndrome—and found they share many similarities in symptoms (like fatigue and pain), how they affect daily life, and how they respond to laboratory tests. The researchers discovered that many patients have more than one of these conditions at the same time, suggesting they may be related or overlap in important ways.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceReview-NarrativeEditor reviewed

Functional somatic syndromes: one or many?

Wessely, S, Nimnuan, C, Sharpe, M·Lancet (London, England)·1999

This study looked at several long-term illnesses that cause many physical symptoms but don't show obvious damage on standard medical tests, including ME/CFS and irritable bowel syndrome. The researchers found that these conditions have much more in common with each other than previously thought—they affect similar types of patients, cause overlapping symptoms, and respond to treatment in similar ways. Rather than treating each condition as completely separate, the authors suggest doctors and researchers should think of them as related conditions on a spectrum.

Diagnostics
E0 ConsensusPEM not requiredPreliminaryReview-NarrativeEditor reviewed

Review of juvenile primary fibromyalgia and chronic fatigue syndrome.

Breau, L M, McGrath, P J, Ju, L H·Journal of developmental and behavioral pediatrics : JDBP·1999

This review examined research on fibromyalgia and chronic fatigue syndrome (ME/CFS) in children. The authors found that these conditions in young people may work differently than they do in adults, and that they might be more closely related to each other than previously thought. The review suggests that these illnesses are likely caused by biological and genetic factors rather than psychological problems.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceReview-NarrativeEditor reviewed

Fibromyalgia and chronic fatigue syndrome: similarities and differences.

Buchwald, D·Rheumatic diseases clinics of North America·1996

This review compared ME/CFS and fibromyalgia (FM), two conditions that cause fatigue, muscle pain, and sleep problems. The researchers found that these two illnesses are very similar in their symptoms and how they affect people's lives, even though doctors use different criteria to diagnose them. Some patients have both conditions at the same time, which makes their suffering worse.

SleepDiagnostics
E0 ConsensusPEM not requiredPreliminaryEditorialEditor reviewed

Fibromyalgia, chronic fatigue, and myofascial pain syndromes.

Goldenberg, D L·Current opinion in rheumatology·1992

This review examined research published on fibromyalgia and chronic fatigue syndrome, looking at what treatments work best and how these conditions are diagnosed. Researchers found that while many studies have been done, no single treatment has proven highly effective for either condition, and the way doctors diagnose chronic fatigue syndrome needs to be improved and made more consistent.

Diagnostics
E0 ConsensusPEM not requiredModerate confidenceSystematic-ReviewEditor reviewed

The differential diagnosis of tiredness: a systematic review.

Stadje, Rebekka, Dornieden, Katharina, Baum, Erika et al.·BMC family practice·2016

This study reviewed 26 previous research studies about why people feel tired when they visit their doctor. The researchers found that serious physical diseases are actually quite rare in tired patients—only about 4% have a serious organic condition. Depression was much more common, affecting about 18% of people who complain of tiredness. The main message is that doctors should focus on checking for depression and emotional stress rather than ordering extensive tests for serious diseases in most cases.

Diagnostics
E1 ReplicatedPEM requiredModerate confidenceObservationalEditor reviewed

Cardiopulmonary exercise testing and post-exertional malaise in ME/CFS: A retrospective analysis

Staci R. Stevens, Christopher R. Snell, Jared N. Stevens et al.·Journal of Translational Medicine·2018·n=51

ME/CFS patients underwent two consecutive days of cardiopulmonary exercise testing (CPET). On the second day, patients showed significantly reduced VO2 max and anaerobic threshold compared to the first day — and compared to healthy and disease controls who recovered normally. This objective impairment matches the subjective PEM experience.

DiagnosticsPost-Exertional Malaise
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Improving myalgic encephalomyelitis population sampling: Applying an online respondent-driven method to address biases in G93.3 register data.

Kielland, Anne, Liu, Jing, Tyldum, Guri et al.·Journal of health psychology·2026

This study looked at how well official medical records capture ME/CFS cases and who gets diagnosed. Researchers found that medical register data misses many cases and disproportionately underrepresents people from lower-income backgrounds. They used a new online method to find ME/CFS patients more accurately and checked whether official diagnoses matched recognized diagnostic criteria.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCase-ControlEditor reviewed

ICD-10 Diagnoses prior to ME/CFS diagnosis in children and young people suggest potential early diagnostic indicators.

Wirth, Marielle, Haastert, Burkhard, Linnenkamp, Ute et al.·Scientific reports·2026

This study looked at medical records of young people (ages 6-27) diagnosed with ME/CFS to see what health problems they had in the year before their diagnosis. Researchers found that certain conditions—like fatigue, depression, pain disorders, and post-COVID-19 condition—appeared more often in people who later developed ME/CFS compared to similar young people who didn't develop it. This suggests these earlier diagnoses might be early warning signs or related to ME/CFS development, though the study cannot prove they actually caused ME/CFS.

Diagnostics
E2 ModeratePEM unclearModerate confidenceBiobank-ResourceEditor reviewed

Defining a High-Quality Myalgic Encephalomyelitis/Chronic Fatigue Syndrome cohort in UK Biobank.

Samms, Gemma L, Ponting, Chris P·NIHR open research·2025

This study looked at how ME/CFS is identified in UK Biobank, a large database of health information from hundreds of thousands of people. Researchers found that about 1 in 100 UK Biobank participants had some evidence of ME/CFS, but only about one-third had strong, consistent evidence across multiple records. When they accounted for people too ill to participate in the study, they estimated that around 410,000 people in the UK have ME/CFS.

Diagnostics
E2 ModeratePEM unclearModerate confidenceRegistry-ResourceEditor reviewed

Unequal access to diagnosis of myalgic encephalomyelitis in England.

Samms, Gemma Louise, Ponting, Chris P·BMC public health·2025

This study examined NHS records from England to understand how many people have ME/CFS and whether diagnosis is fair across different groups. Researchers found that about 100,000 people in England have been officially diagnosed with ME/CFS, but the actual number may be much higher—around 404,000 in the UK. The diagnosis rates varied significantly depending on gender, age, ethnicity, and where people live, suggesting some patients are being missed.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Classification Accuracy and Description of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in an Integrated Health Care System, 2006-2017.

Liles, Elizabeth G, Irving, Stephanie A, Koppolu, Padma et al.·The Permanente journal·2024

This study looked at how often ME/CFS is diagnosed in a large health care system by checking electronic medical records from 2006 to 2017. Researchers found that while doctors used ME/CFS diagnosis codes for over 500 patients, only about 34% of the cases they reviewed actually matched the real diagnostic criteria for ME/CFS. This shows that relying only on diagnosis codes in medical records can give an inaccurate picture of how many people truly have ME/CFS.

Diagnostics
E2 ModeratePEM unclearModerate confidenceRegistry-ResourceEditor reviewed

The German Multicenter Registry for ME/CFS (MECFS-R).

Hieber, Hannah, Pricoco, Rafael, Gerrer, Katrin et al.·Journal of clinical medicine·2024

German researchers created a registry to collect detailed health information from ME/CFS patients across multiple medical centers. In their first group of 174 patients, they found that most had a viral illness before developing ME/CFS, with nearly half triggered by COVID-19. Patients reported severe fatigue and greatly reduced quality of life, with significant limitations in daily activities.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

[Systems thinking, subjective findings and diagnostic "pigeonholing" in ME/CFS: A mainly qualitative public health study from a patient perspective].

Habermann-Horstmeier, Lotte, Horstmeier, Lukas Maximilian·Deutsche medizinische Wochenschrift (1946)·2024

This German study asked 544 ME/CFS patients about their experiences getting diagnosed and working with doctors. Patients reported that many doctors don't recognize ME/CFS as a real disease, instead dismissing it as purely psychological. The study found that poor diagnosis experiences and lack of doctor recognition of ME/CFS as a biological multisystem illness significantly damage the relationship between patients and their healthcare providers.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

[What Medical Specialties do ME/CFS Sufferers Consult? A Public Health Study on the need for Better Medical Education and Training].

Habermann-Horstmeier, Lotte, Horstmeier, Lukas Maximilian·Gesundheitswesen (Bundesverband der Arzte des Offentlichen Gesundheitsdienstes (Germany))·2024

This German study surveyed 674 ME/CFS patients to understand how they navigate the healthcare system and how long diagnosis takes. Patients saw an average of 6-15 different doctors from various specialties before getting diagnosed, with the diagnostic journey taking up to 10 years for most people. The study found that doctors often refer patients around based on individual symptoms rather than recognizing ME/CFS as a whole condition, highlighting the urgent need for better training about ME/CFS across all medical fields.

Diagnostics
E2 ModeratePEM unclearModerate confidenceObservationalEditor reviewed

Severe myalgic encephalomyelitis/chronic fatigue syndrome in children and young people: a British Paediatric Surveillance Unit study.

Royston, Alexander Peter, Rai, Manmita, Brigden, Amberly et al.·Archives of disease in childhood·2023

This British study looked at how many children and young people aged 5-16 have severe ME/CFS, a condition that causes extreme tiredness and makes it very difficult to do everyday activities. Researchers found that severe ME/CFS is uncommon in children, but when it does occur, it causes major disability—most affected young people missed almost all their schooling. The study also found that children got diagnosed relatively quickly, within about 5-6 months of when their symptoms started.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

A Quick and Practical Approach to Secure a Chronic Fatigue Syndrome Diagnosis: The Novel Functional Limitation Index.

Corbalán, Juan Antonio, Feltes, Gisela, Silva, Daniela et al.·Journal of clinical medicine·2023

Researchers developed a simple test called the Functional Limitation Index (FLI) to help doctors diagnose ME/CFS more quickly and objectively. The test uses measurements from exercise testing and breathing tests to identify how much a person's physical function is impaired. In their study, the FLI successfully distinguished ME/CFS patients from healthy people and athletes with high accuracy.

Diagnostics
E2 ModeratePEM unclearModerate confidenceLongitudinalEditor reviewed

Different risk factors distinguish myalgic encephalomyelitis/chronic fatigue syndrome from severe fatigue.

Palacios, Natalia, Molsberry, Samantha, Fitzgerald, Kathryn C et al.·Scientific reports·2023

This study examined whether ME/CFS is simply an extreme version of regular fatigue, or if it's a fundamentally different condition. Researchers surveyed over 41,000 nurses and found that ME/CFS and severe fatigue have different risk factors—meaning different things cause them. This suggests that ME/CFS is a distinct condition with its own underlying biology, not just 'really bad tiredness.'

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Health system support among patients with ME/CFS in Switzerland.

Tschopp, Rea, König, Rahel S, Rejmer, Protazy et al.·Journal of Taibah University Medical Sciences·2023

This Swiss study surveyed 169 ME/CFS patients to understand their experiences with the healthcare system. Patients faced long delays in getting diagnosed (averaging 6.7 years), saw many doctors before getting correct answers (11.1 appointments on average), and were frequently told their symptoms were psychological rather than physical. The study found that doctors in Switzerland lack knowledge about ME/CFS, leading to frustration, inappropriate treatments, and some patients traveling abroad for proper diagnosis.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Orthostatic intolerance and neurocognitive impairment in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).

Gaglio, Caroline L, Islam, Mohammed F, Cotler, Joseph et al.·Epidemiologic methods·2022

This study looked at how often people with ME/CFS experience two symptoms that doctors use to diagnose the condition: difficulty thinking clearly (brain fog, memory problems) and dizziness when standing up. The researchers found that nearly all participants reported thinking and memory problems, while only a small number had standing-up dizziness without also having cognitive problems. This suggests these two symptoms overlap heavily in ME/CFS patients.

Autonomic Nervous SystemDiagnostics
E2 ModeratePEM unclearModerate confidenceMethods-PaperEditor reviewed

Comparing Operationalized Approaches for Substantial Reduction of Functioning in Chronic Fatigue Syndrome and Myalgic Encephalomyelitis.

Wiedbusch, Elzbieta, Jason, Leonard A·Archives of community medicine·2022

This study looked at five different ways to measure how much ME/CFS reduces a person's ability to function in daily life—something that is a key part of diagnosis. Using a large international group of over 2,300 patients and 359 healthy controls, researchers found that all five methods worked reasonably well, but a simple single-question approach was the best at identifying who actually had ME/CFS. This suggests doctors could use an easier, faster method to assess this important symptom.

Diagnostics
E2 ModeratePEM requiredModerate confidenceCross-SectionalEditor reviewed

Separating Patients with SEID from Those with CFS in the French ME/CFS Association, with Some Thoughts on Nomenclature.

Campagne, Julien, Fornasieri, Isabelle, Andreani, Barbara et al.·Diagnostics (Basel, Switzerland)·2022

Researchers surveyed French ME/CFS patients to see how many met the newer diagnostic criteria called SEID (Systemic Exertion Intolerance Disease), proposed in 2015. They found that about 84% of patients in the survey met SEID criteria, and certain symptoms like unrefreshing sleep, brain fog, and problems with blood pressure changes were especially useful for identifying SEID patients. However, most patients didn't strongly prefer the new SEID name over ME/CFS, suggesting the medical community should work with patients to find better terminology.

Diagnostics
E2 ModeratePEM unclearPreliminaryCase-ControlEditor reviewed

Saliva Fatigue Biomarker Index As a Marker for Severe Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in a Community Based Sample.

Jason, Leonard A, Kalns, John, Richarte, Alicia et al.·Fatigue : biomedicine, health & behavior·2021

Researchers tested whether a simple saliva test could help diagnose severe ME/CFS in children and teens. They measured two protein fragments in saliva from young people with ME/CFS and compared them to healthy controls. The study found that this 'Fatigue Biomarker Index' showed significant differences between those with severe ME/CFS and healthy youth, suggesting it might one day be a useful objective test to help doctors diagnose the condition.

Diagnostics
E2 ModeratePEM unclearPreliminaryCross-SectionalEditor reviewed

Clinical Profile and Aspects of Differential Diagnosis in Patients with ME/CFS from Latvia.

Krumina, Angelika, Vecvagare, Katrine, Svirskis, Simons et al.·Medicina (Kaunas, Lithuania)·2021

This study looked at 65 people with ME/CFS in Latvia to understand their main symptoms and how the condition differs from simple tiredness. Researchers found that people with ME/CFS commonly experience fatigue, muscle pain, joint pain, and sleep problems—more often than people without ME/CFS. When patients had other health conditions alongside ME/CFS, their symptoms tended to be more severe.

Pain and SensitizationSleepDiagnostics
E2 ModeratePEM unclearPreliminaryCross-SectionalEditor reviewed

Medical School Education on Myalgic Encephalomyelitis.

Muirhead, Nina, Muirhead, John, Lavery, Grace et al.·Medicina (Kaunas, Lithuania)·2021

This study looked at how much medical schools in the UK teach doctors-in-training about ME/CFS. Researchers sent questionnaires to all 34 UK medical schools and found that only about half actually teach ME/CFS, and the teaching varies widely between schools. Most schools said they would welcome better teaching materials and resources about ME/CFS, suggesting doctors need more education on how to recognize and diagnose this condition.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Perceptions of European ME/CFS Experts Concerning Knowledge and Understanding of ME/CFS among Primary Care Physicians in Europe: A Report from the European ME/CFS Research Network (EUROMENE).

Cullinan, John, Pheby, Derek F H, Araja, Diana et al.·Medicina (Kaunas, Lithuania)·2021

ME/CFS experts across Europe were asked what they think family doctors know about ME/CFS and how to help them understand it better. The experts reported serious concerns: about 60% of ME/CFS patients go undiagnosed because family doctors lack knowledge about the condition, don't believe it's real, or don't know how to manage it. Most experts agreed that better training for doctors at all levels would help.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

The Prevalence of Pediatric Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in a Community‑Based Sample.

Jason, Leonard A, Katz, Ben Z, Sunnquist, Madison et al.·Child & youth care forum·2020

Researchers studied over 10,000 children and teenagers in the Chicago area to find out how many have ME/CFS. They found that about 0.75% (roughly 1 in 133) young people have the condition, with higher rates among African American and Latino youth. Importantly, less than 5% of these children had been diagnosed before the study, meaning many young people with ME/CFS are going unrecognized by doctors.

Diagnostics
E2 ModeratePEM requiredPreliminaryMechanisticEditor reviewed

A nanoelectronics-blood-based diagnostic biomarker for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

Rahim Esfandyarpour, Aref Kashi, Maya Nemat-Gorgani et al.·Proceedings of the National Academy of Sciences (PNAS)·2019·n=40

Stanford researchers developed a nanoelectronics device that detects immune cell changes using a tiny electrical sensor. When salt stress was applied to blood samples, ME/CFS patient samples showed a distinctly different electrical response compared to healthy controls. This 'nano-needle' assay could potentially serve as an objective diagnostic test.

BiomarkersDiagnostics
E2 ModeratePEM requiredModerate confidenceCross-SectionalEditor reviewed

Myalgic encephalomyelitis/chronic fatigue Syndrome (ME/CFS): Investigating care practices pointed out to disparities in diagnosis and treatment across European Union.

Strand, Elin B, Nacul, Luis, Mengshoel, Anne Marit et al.·PloS one·2019

This study looked at how ME/CFS is diagnosed and treated across 17 European countries by surveying doctors and health organizations. The researchers found that different countries use different diagnostic tests and treatment approaches, with no standard way of doing things across Europe. The study shows that there is confusion and inconsistency in how ME/CFS patients are evaluated and cared for, which suggests that Europe needs to agree on common guidelines.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Myalgic encephalomyelitis and chronic fatigue syndrome case definitions: effects of requiring a substantial reduction in functioning.

Scartozzi, Samantha, Sunnquist, Madison, Jason, Leonard A·Fatigue : biomedicine, health & behavior·2019

ME/CFS diagnoses require doctors to confirm that patients have a significant drop in their ability to function compared to before they got sick. However, there's no clear agreement on how much of a drop counts as 'significant.' This study looked at over 1,000 people with ME/CFS to see whether this requirement actually helps doctors identify who has the illness. The researchers found that when diagnostic criteria clearly describe which symptoms to look for and how severe they should be, the 'significant drop in functioning' requirement may not be necessary.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceObservationalEditor reviewed

Epidemiology of paediatric chronic fatigue syndrome in Australia.

Knight, Sarah, Elders, Shane, Rodda, Jill et al.·Archives of disease in childhood·2019

This study looked at how many Australian children develop ME/CFS and what their experiences are like. Researchers tracked newly diagnosed cases over one year and found that the condition is quite rare in children under 10, but becomes more common in teenagers. Interestingly, the rates were very different depending on where children lived in Australia, suggesting some areas may be better at recognizing and diagnosing the condition than others.

Diagnostics
E2 ModeratePEM unclearModerate confidenceObservationalEditor reviewed

Healthcare Utilization in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Analysis of US Ambulatory Healthcare Data, 2000-2009.

Bae, Jaeyong, Lin, Jin-Mann S·Frontiers in pediatrics·2019

This study examined how often people with ME/CFS visited doctors in the United States between 2000 and 2009. Researchers found that about 2.9 million visits were coded as ME/CFS-related during this period, with most patients being women in their 40s and 50s. Many patients with ME/CFS also had other health conditions like depression, high blood pressure, and diabetes, making their care more complicated.

Diagnostics
E2 ModeratePEM requiredModerate confidenceCross-SectionalEditor reviewed

Systemic exertion intolerance disease diagnostic criteria applied on an adolescent chronic fatigue syndrome cohort: evaluation of subgroup differences and prognostic utility.

Asprusten, Tarjei Tørre, Sulheim, Dag, Fagermoen, Even et al.·BMJ paediatrics open·2018

This study looked at whether a diagnostic checklist called SEID (Systemic Exertion Intolerance Disease) could reliably identify and predict outcomes in teenagers with ME/CFS. The researchers compared 120 adolescents who did or didn't meet the SEID criteria and found that the criteria didn't actually help predict who would improve over time. Interestingly, teens who met the SEID criteria were more likely to show symptoms of depression, which raises questions about whether the criteria are truly measuring ME/CFS itself.

Diagnostics
E2 ModeratePEM unclearPreliminaryObservationalEditor reviewed

Defining the prevalence and symptom burden of those with self-reported severe chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME): a two-phase community pilot study in the North East of England.

Strassheim, Victoria Jane, Sunnquist, Madison, Jason, Leonard A et al.·BMJ open·2018

This study tried to find out how many people in Northern England have severe ME/CFS and what symptoms they experience. Researchers sent questionnaires to people with ME/CFS and then invited five participants to take part in home-based research visits. The study found that people with severe ME/CFS want to participate in research but struggle with their high symptom burden and poor quality of life, which makes completing research visits challenging.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Operationalizing Substantial Reduction in Functioning Among Young Adults with Chronic Fatigue Syndrome.

Gleason, Kristen D, Stoothoff, Jamie, McClellan, Damani et al.·International journal of behavioral medicine·2018

This study looked for the best way to measure the 'substantial reduction in functioning' that is required for ME/CFS diagnosis. Researchers used a standard health survey (SF-36) with young adults (ages 18-29) who had ME/CFS and compared them to people without the condition. They found that specific cutoff scores on four areas of the survey—physical functioning, general health, role physical (ability to work), and social functioning—could accurately identify who has ME/CFS.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

A reexamination of the cognitive behavioral model of chronic fatigue syndrome.

Sunnquist, Madison, Jason, Leonard A·Journal of clinical psychology·2018

This study tested whether the idea that ME/CFS is caused or worsened mainly by unhelpful thoughts and not being active enough actually explains what happens to patients with ME/CFS. Researchers looked at 990 people with ME/CFS and found this explanation didn't fit well, especially for people who met stricter diagnostic criteria. The findings suggest that ME/CFS may work differently than this model assumes.

Diagnostics
E2 ModeratePEM requiredModerate confidenceCross-SectionalEditor reviewed

Examining those Meeting IOM Criteria Versus IOM Plus Fibromyalgia.

Jason, Leonard A, McManimen, Stephanie, Sunnquist, Madison et al.·Neurology (E-Cronicon)·2017

This study compared two groups of people with ME/CFS: those who met the official Institute of Medicine diagnostic criteria, and those who met those same criteria plus also had fibromyalgia (a condition involving widespread pain and tender points). The researchers found that patients with both ME/CFS and fibromyalgia experienced more severe symptoms and greater functional impairment across many areas than those with ME/CFS alone.

Diagnostics
E2 ModeratePEM requiredModerate confidenceCross-SectionalEditor reviewed

Clinical Criteria Versus a Possible Research Case Definition in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis.

Jason, Leonard A, McManimen, Stephanie, Sunnquist, Madison et al.·Fatigue : biomedicine, health & behavior·2017

This study compared different ways of defining ME/CFS to see which one best identifies the sickest patients. Researchers looked at over 1,000 patients from multiple countries and found that using stricter criteria—specifically focusing on people who are homebound and meet core ME/CFS symptoms—identified a group with more severe symptoms and greater disability than the broader clinical definition. The researchers suggest that having a clear, standardized research definition would help scientists compare patients more fairly across different studies.

Diagnostics
E2 ModeratePEM unclearModerate confidenceObservationalEditor reviewed

Multi-Site Clinical Assessment of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (MCAM): Design and Implementation of a Prospective/Retrospective Rolling Cohort Study.

Unger, Elizabeth R, Lin, Jin-Mann S, Tian, Hao et al.·American journal of epidemiology·2017

Researchers created a large study called MCAM to better understand ME/CFS by collecting standardized health information from patients across seven U.S. clinics. They also enrolled healthy people and patients with similar illnesses for comparison. The study tracked patients over time, collected samples for future research, and documented how doctors were treating ME/CFS patients, aiming to identify different types of ME/CFS and find tests that could help diagnosis.

Diagnostics
E2 ModeratePEM requiredModerate confidenceCross-SectionalEditor reviewed

A Comparison of Case Definitions for Myalgic Encephalomyelitis and Chronic Fatigue Syndrome.

Sunnquist, Madison, Jason, Leonard A, Nehrke, Pamela et al.·Journal of chronic diseases and management·2017

This study compared two different sets of diagnostic criteria used to identify ME/CFS patients. Researchers found that 76% of people diagnosed with chronic fatigue syndrome met the newer Institute of Medicine criteria, but only 44% met the revised London criteria. The London criteria identified patients who were more severely physically impaired, suggesting that different diagnostic tools can identify different groups of patients.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Chronic Fatigue Syndrome prevalence is grossly overestimated using Oxford criteria compared to Centers for Disease Control (Fukuda) criteria in a U.S. population study.

Baraniuk, James N·Fatigue : biomedicine, health & behavior·2017

This study compared two different sets of diagnostic criteria for ME/CFS by surveying a large representative sample of Americans. The researchers found that using the less strict Oxford criteria identified far more people as having ME/CFS (about 20-25%) compared to the stricter CDC (Fukuda) criteria (about 2%). When they looked more carefully at who truly had ME/CFS using both fatigue severity and other symptom requirements, they found that 85% of people labeled as CFS by the Oxford criteria didn't actually meet the stricter definition.

Diagnostics
E2 ModeratePEM requiredPreliminaryObservationalEditor reviewed

Incidence rates of Guillain Barré (GBS), chronic fatigue/systemic exertion intolerance disease (CFS/SEID) and postural orthostatic tachycardia syndrome (POTS) prior to introduction of human papilloma virus (HPV) vaccination among adolescent girls in Finland, 2002-2012.

Skufca, J, Ollgren, J, Ruokokoski, E et al.·Papillomavirus research (Amsterdam, Netherlands)·2017

This Finnish study looked at how often three conditions—ME/CFS, Guillain-Barré syndrome (GBS), and POTS—were diagnosed in teenage girls between 2002 and 2012, before the HPV vaccine program started. Researchers wanted to establish baseline numbers to help evaluate vaccine safety in the future. They found these conditions were relatively rare, though ME/CFS and POTS diagnoses increased over the decade studied.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCase-ControlEditor reviewed

Are current chronic fatigue syndrome criteria diagnosing different disease phenotypes?

Maclachlan, Laura, Watson, Stuart, Gallagher, Peter et al.·PloS one·2017

This study looked at whether different diagnostic criteria for ME/CFS are actually identifying the same disease or different versions of it. Researchers tested 49 ME/CFS patients and 10 healthy controls using questionnaires and objective tests of heart function and thinking ability. They found that patients reported more autonomic and cognitive symptoms than controls, but objective heart tests didn't show clear differences—though different patient subgroups did show different levels of impairment on cognitive testing.

Autonomic Nervous SystemDiagnosticsCognitive Impairment
E2 ModeratePEM not requiredHigher confidenceMethods-PaperEditor reviewed

The assessment of fatigue: Psychometric qualities and norms for the Checklist individual strength.

Worm-Smeitink, M, Gielissen, M, Bloot, L et al.·Journal of psychosomatic research·2017

This study tested a questionnaire called the Checklist Individual Strength (CIS) that measures different types of fatigue, including how tired people feel, difficulty concentrating, lack of motivation, and reduced activity levels. Researchers gave this questionnaire to nearly 2,300 healthy people and over 5,000 patients with chronic fatigue to see if it accurately identifies severe fatigue. They found the CIS works well for measuring fatigue and recommended adjusting the score that indicates 'severe fatigue' from 35 to 40 points for ME/CFS research.

Diagnostics
E2 ModeratePEM unclearPreliminaryCross-SectionalEditor reviewed

Can physical assessment techniques aid diagnosis in people with chronic fatigue syndrome/myalgic encephalomyelitis? A diagnostic accuracy study.

Hives, Lucy, Bradley, Alice, Richards, Jim et al.·BMJ open·2017

Researchers tested whether five simple physical examination techniques could help doctors quickly identify ME/CFS. They examined 52 people with ME/CFS and 42 people without the condition, using trained practitioners to check for specific physical signs like spine problems and tender points. The study found that two of these physical signs were reliable and accurate enough to potentially help with diagnosis, suggesting that quick physical checks might be a useful screening tool.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCase-ControlEditor reviewed

Health care resource use by patients before and after a diagnosis of chronic fatigue syndrome (CFS/ME): a clinical practice research datalink study.

Collin, Simon M, Bakken, Inger J, Nazareth, Irwin et al.·BMC family practice·2017

This study looked at doctor visits, tests, prescriptions, and referrals for people diagnosed with ME/CFS compared to similar people without the condition. Researchers found that people who were later diagnosed with ME/CFS visited their doctors much more frequently—both years before they received their diagnosis and for at least 10 years afterward. This suggests that people with ME/CFS have ongoing, significant health needs that require more medical care than the general population.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceMethods-PaperEditor reviewed

Methods of applying the 1994 case definition of chronic fatigue syndrome - impact on classification and observed illness characteristics.

Unger, E R, Lin, J-M S, Tian, H et al.·Population health metrics·2016

Researchers tested two different ways of diagnosing ME/CFS using the same official criteria to see if the method mattered. One method asked patients direct questions about fatigue and symptoms, while the other used standardized questionnaires with scoring thresholds. They found that both methods identified similar people as having ME/CFS (about 82% agreement), but the questionnaire method identified somewhat more cases without them being less severely ill.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Validation of the qi blood yin yang deficiency questionnaire on chronic fatigue.

Kim, Jihye, Ku, Boncho, Kim, Keun Ho·Chinese medicine·2016

This study tested a questionnaire designed to identify different patterns of chronic fatigue based on Traditional Korean Medicine concepts (qi, blood, yin, and yang imbalances). Researchers gave the questionnaire to 129 people with chronic fatigue and found that it reliably distinguished between different types of fatigue patterns. The questionnaire may help doctors better understand what kind of fatigue a patient has.

Diagnostics
E2 ModeratePEM requiredModerate confidenceCross-SectionalEditor reviewed

Epidemiological characteristics of chronic fatigue syndrome/myalgic encephalomyelitis in Australian patients.

Johnston, Samantha C, Staines, Donald R, Marshall-Gradisnik, Sonya M·Clinical epidemiology·2016

This study looked at 535 Australian patients with ME/CFS to understand who gets the disease and what symptoms they experience. Researchers found that ME/CFS mainly affects middle-aged women who are well-educated, and often starts after infections like the flu or gut illnesses, or during stressful periods. The most common symptoms included extreme fatigue, brain fog, poor sleep, headaches, muscle and joint pain, and sensitivity to temperature changes.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Factors facilitating patient satisfaction among women with medically unexplained long-term fatigue: A relational perspective.

Lian, Olaug S, Hansen, Anne Helen·Health (London, England : 1997)·2016

This study surveyed 431 women with ME/CFS about their experiences with doctors in Norway. The researchers found that patients were most satisfied when their doctor understood their illness, saw them regularly, and referred them to specialists. The most important factor was feeling like an equal partner with their doctor rather than just being told what to do.

Diagnostics
E2 ModeratePEM unclearModerate confidenceRegistry-ResourceEditor reviewed

Comorbidities treated in primary care in children with chronic fatigue syndrome / myalgic encephalomyelitis: A nationwide registry linkage study from Norway.

Bakken, Inger J, Tveito, Kari, Aaberg, Kari M et al.·BMC family practice·2016

This large Norwegian study looked at health problems that children with ME/CFS commonly experience in primary care compared to other children. Children with ME/CFS were much more likely to have records of extreme tiredness, depression, anxiety, migraines, and muscle pain. Interestingly, many children with ME/CFS had a recent infection (especially infectious mononucleosis) before their diagnosis, suggesting infections might play a role in developing the condition.

Diagnostics
E2 ModeratePEM unclearPreliminaryMethods-PaperEditor reviewed

Issues in Estimating Rates of Pediatric Chronic Fatigue Syndrome and Myalgic Encephalomyelitis in a Community-based Sample.

Jason, Leonard A, Katz, Ben Z, Mears, Cynthia et al.·Avicenna journal of neuropsychophysiology·2015

This study looked at how common ME/CFS is in children living in regular communities, not just in doctor's offices. Researchers used a two-step approach: first they screened children for ME/CFS-like symptoms, then they did detailed medical and mental health evaluations to confirm diagnoses. The study also compared children with ME/CFS to healthy children without the condition.

Diagnostics
E2 ModeratePEM requiredModerate confidenceCross-SectionalEditor reviewed

Unintended Consequences of not Specifying Exclusionary Illnesses for Systemic Exertion Intolerance Disease.

Jason, Leonard A, Sunnquist, Madison, Kot, Bobby et al.·Diagnostics (Basel, Switzerland)·2015

Researchers studied a new proposed name and definition for ME/CFS called SEID (Systemic Exertion Intolerance Disease). They found that the new definition was much looser than the old one and incorrectly labeled people with depression and other illnesses as having SEID when they didn't actually have ME/CFS. This means the new definition could overestimate how many people have ME/CFS.

Diagnostics
E2 ModeratePEM requiredPreliminaryCross-SectionalEditor reviewed

A comparison of health status in patients meeting alternative definitions for chronic fatigue syndrome/myalgic encephalomyelitis.

Johnston, Samantha C, Brenu, Ekua W, Hardcastle, Sharni L et al.·Health and quality of life outcomes·2014

This study compared two different sets of criteria used to diagnose ME/CFS and looked at how severely the disease affected patients who met each definition. Researchers found that patients meeting the stricter International Consensus Criteria (ICC) definition had worse physical functioning, more pain, and greater disability than those who only met the older CDC criteria. This suggests that the ICC criteria identify a more severely affected group of patients within the broader ME/CFS population.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

How is paediatric chronic fatigue syndrome/myalgic encephalomyelitis diagnosed and managed by paediatricians? An Australian Paediatric Research Network Study.

Knight, Sarah, Harvey, Adrienne, Towns, Susan et al.·Journal of paediatrics and child health·2014

This study asked Australian pediatricians how they diagnose and treat children with ME/CFS. Only 39% of the doctors who responded said they actually diagnose and manage this condition, and they used very different approaches from each other. The doctors found that children with ME/CFS often also have anxiety, depression, and other conditions, and most used a team approach involving teachers, physiotherapists, and psychologists.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

A Chronic Fatigue Syndrome (CFS) severity score based on case designation criteria.

Baraniuk, James N, Adewuyi, Oluwatoyin, Merck, Samantha Jean et al.·American journal of translational research·2013

This study created a scoring system to help doctors better identify and measure ME/CFS severity by combining eight common symptoms (fatigue, pain, cognitive problems, sleep issues, and post-exertion exhaustion). Researchers found that a total symptom score of 14 or higher, combined with moderate-to-severe fatigue, accurately distinguished ME/CFS patients from healthy people. This scoring system was highly consistent and may help match patients to specific disease subtypes.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Contrasting Chronic Fatigue Syndrome versus Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Jason, Leonard A, Brown, Abigail, Evans, Meredyth et al.·Fatigue : biomedicine, health & behavior·2013

This study compared two different sets of diagnostic criteria used to identify ME/CFS patients. Researchers found that the Canadian criteria are stricter and identify patients who tend to be more severely affected, while the older Fukuda criteria cast a wider net. This suggests that the criteria used to diagnose someone with ME/CFS can significantly affect who gets identified as having the condition.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Undiagnosed and comorbid disorders in patients with presumed chronic fatigue syndrome.

Mariman, An, Delesie, Liesbeth, Tobback, Els et al.·Journal of psychosomatic research·2013

Researchers studied nearly 280 patients who came to a specialized clinic thinking they had ME/CFS, and gave them thorough medical, sleep, and mental health assessments. They found that only about 23% actually had clear-cut ME/CFS; most others had sleep problems like sleep apnea, depression or anxiety, or a combination of these conditions. This suggests that when people feel persistently exhausted, many different medical and mental health issues could be the real cause.

Diagnostics
E2 ModeratePEM requiredModerate confidenceObservationalEditor reviewed

Paediatric chronic fatigue syndrome: complex presentations and protracted time to diagnosis.

Knight, Sarah, Harvey, Adrienne, Lubitz, Lionel et al.·Journal of paediatrics and child health·2013

This study looked at 59 young people (average age 15) diagnosed with ME/CFS at a specialist clinic in Australia to understand how the illness affects them and how long it takes to get diagnosed. Researchers found that young people typically wait over a year after their symptoms start before getting a diagnosis, and most experience significant problems with school attendance and daily activities. The most common symptoms included extreme tiredness, sleep problems, pain, and difficulty thinking clearly.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceObservationalEditor reviewed

Prevalence, incidence, and classification of chronic fatigue syndrome in Olmsted County, Minnesota, as estimated using the Rochester Epidemiology Project.

Vincent, Ann, Brimmer, Dana J, Whipple, Mary O et al.·Mayo Clinic proceedings·2012

This study looked at how many people in one county had ME/CFS by reviewing medical records from 1998-2002. Researchers found that about 71 out of every 100,000 people had ME/CFS, and about 13 out of every 100,000 per year were newly diagnosed. Importantly, they discovered that 70% of people initially suspected of having ME/CFS actually had other medical conditions that explained their fatigue instead.

Diagnostics
E2 ModeratePEM unclearModerate confidenceMethods-PaperEditor reviewed

Data mining: comparing the empiric CFS to the Canadian ME/CFS case definition.

Jason, Leonard A, Skendrovic, Beth, Furst, Jacob et al.·Journal of clinical psychology·2012

This study compared two different sets of diagnostic criteria used to identify ME/CFS patients. Researchers used a computer-based analysis technique to test which questions from patient surveys were most helpful in accurately diagnosing the illness. They found that the Canadian criteria correctly identified 87% of ME/CFS patients, while the older empiric criteria identified about 79%, suggesting the Canadian approach may be more effective for diagnosis.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Alternative diagnoses to chronic fatigue syndrome in referrals to a specialist service: service evaluation survey.

Devasahayam, Anoop, Lawn, Tara, Murphy, Maurice et al.·JRSM short reports·2012

This study looked at patients referred to a specialist ME/CFS clinic to see how often doctors correctly identified ME/CFS versus other conditions. Researchers found that about half of all referred patients actually had different medical or psychiatric conditions instead of ME/CFS—most commonly sleep disorders or depression. This shows that careful specialist assessment is important to make sure patients get the right diagnosis.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Contrasting case definitions for chronic fatigue syndrome, Myalgic Encephalomyelitis/chronic fatigue syndrome and myalgic encephalomyelitis.

Jason, Leonard A, Brown, Abigail, Clyne, Erin et al.·Evaluation & the health professions·2012

This study looked at patients diagnosed with chronic fatigue syndrome (CFS) using an older definition and compared how many of them would also meet two newer, stricter definitions: ME/CFS and ME. Researchers found that patients meeting the newer, stricter definitions had more severe symptoms and greater disability than those who only met the older CFS definition. This suggests that the newer definitions may help doctors identify the most severely affected patients.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Prevalence of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) in three regions of England: a repeated cross-sectional study in primary care.

Nacul, Luis C, Lacerda, Eliana M, Pheby, Derek et al.·BMC medicine·2011

This study looked at how many people in three regions of England have ME/CFS by checking medical records and asking doctors directly about their patients. Depending on which diagnostic criteria they used, between 0.03% and 0.2% of adults had ME/CFS—meaning roughly 1 in 500 to 1 in 3,300 people. The study shows ME/CFS is a real and significant health problem affecting many people who need better support and care.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Chronic fatigue syndrome: labels, meanings and consequences.

Wojcik, Wojtek, Armstrong, David, Kanaan, Richard·Journal of psychosomatic research·2011

This study surveyed British neurologists to understand how they view ME/CFS and whether they consider it a neurological condition. The results revealed that 84% of neurologists did not view ME/CFS as a neurological disorder, even though it is officially classified as one in the ICD-10 medical coding system. The researchers discuss how the way we label and classify ME/CFS affects how doctors treat patients and how patients understand their own illness.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceRegistry-ResourceEditor reviewed

A Disease Register for ME/CFS: Report of a Pilot Study.

Pheby, Derek, Lacerda, Eliana, Nacul, Luis et al.·BMC research notes·2011

Researchers created a disease register (a database) to identify and track people with ME/CFS in a fair and systematic way. They searched GP records in three regions of England and found 510 patients with unexplained chronic fatigue, of which 160 agreed to join the register. By following these patients over time, researchers can better understand how ME/CFS progresses and use this group for future studies.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Measuring substantial reductions in functioning in patients with chronic fatigue syndrome.

Jason, Leonard, Brown, Molly, Evans, Meredyth et al.·Disability and rehabilitation·2011

ME/CFS diagnosis requires showing that a person can do much less in work, school, social activities, or personal care than they could before becoming ill. However, doctors have struggled with how to measure this decline accurately. This study tested which questions from a standard health survey best identify real, substantial losses in functioning in ME/CFS patients, finding that questions about energy levels, physical activities, and social participation worked best.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Fatigue and chronic fatigue syndrome-like complaints in the general population.

van't Leven, Marjolein, Zielhuis, Gerhard A, van der Meer, Jos W et al.·European journal of public health·2010

This study surveyed over 9,000 Dutch adults to understand how common fatigue is in the general population and what factors might be associated with it. Researchers found that about 1% of adults experience fatigue meeting CFS-like criteria, and 30% experience longer-lasting fatigue. People with CFS-like fatigue were more likely to be female, less physically active, obese, and taking painkillers regularly.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

The Newcastle NHS Chronic Fatigue Syndrome Service: not all fatigue is the same.

Newton, J L, Mabillard, H, Scott, A et al.·The journal of the Royal College of Physicians of Edinburgh·2010

This study looked at patients referred to a specialist fatigue clinic in Newcastle, England to see how many actually had ME/CFS versus other conditions causing tiredness. The researchers found that 60% of referred patients were diagnosed with ME/CFS, while the remaining 40% had other causes of fatigue—most commonly tiredness from other chronic illnesses, sleep problems, or mental health conditions. This suggests many people with fatigue don't fit ME/CFS criteria but still need help managing their symptoms.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

U.S. healthcare providers' knowledge, attitudes, beliefs, and perceptions concerning Chronic Fatigue Syndrome.

Brimmer, Dana J, Fridinger, Frederick, Lin, Jin-Mann S et al.·BMC family practice·2010

Researchers surveyed over 4,000 U.S. doctors and nurses to find out how much they know about ME/CFS and what they think about diagnosing and treating it. Most healthcare providers had heard of ME/CFS and knew its basic symptoms, but many said they rarely diagnose it. The study found that doctors got their information mainly from medical journals, the internet, and continuing education courses.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

A national cross-sectional survey of diagnosed sufferers of myalgic encephalomyelitis/chronic fatigue syndrome: pathways to diagnosis, changes in quality of life and service priorities.

Comiskey, C, Larkan, F·Irish journal of medical science·2010

This study surveyed 211 people in Ireland with a diagnosed ME/CFS to understand their journey to diagnosis and how the illness affected their lives. On average, people visited 4-5 different healthcare services before being diagnosed, and it took nearly 4 years to get a diagnosis (though some waited much longer). Patients reported that their quality of life got significantly worse after developing ME/CFS, and they strongly asked for doctors to have better training and understanding of the condition.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Comparative epidemiology of chronic fatigue syndrome in Brazilian and British primary care: prevalence and recognition.

Cho, Hyong Jin, Menezes, Paulo Rossi, Hotopf, Matthew et al.·The British journal of psychiatry : the journal of mental science·2009

This study looked at how often ME/CFS occurs in two very different cities—London and São Paulo, Brazil—and whether doctors recognize it as a real condition. Researchers surveyed over 6,000 primary care patients and found that ME/CFS affected roughly the same number of people in both places (about 2%). However, while British doctors had diagnosed some cases, Brazilian doctors had not diagnosed any, suggesting that cultural and healthcare system differences affect how the disease is recognized rather than how common it actually is.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Are chronic fatigue and chronic fatigue syndrome valid clinical entities across countries and health-care settings?

Hickie, Ian, Davenport, Tracey, Vernon, Suzanne D et al.·The Australian and New Zealand journal of psychiatry·2009

This large international study analyzed data from nearly 38,000 people across 21 countries to determine whether chronic fatigue and ME/CFS are real, recognizable conditions. Researchers found that people with these conditions share a consistent pattern of five main symptom types—muscle pain and fatigue, thinking difficulties, inflammation-related symptoms, sleep problems, and mood changes—regardless of where they live or which type of doctor they see. This consistency across different countries and healthcare settings provides strong evidence that chronic fatigue and ME/CFS are genuine medical conditions, not just psychiatric problems.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Demographic and clinical aspects of an Italian patient population with chronic fatigue syndrome.

Carlo-Stella, N, Cuccia, M·Reumatismo·2009

This Italian study surveyed patients diagnosed with ME/CFS to understand their symptoms and backgrounds. The researchers found that Italian patients with ME/CFS experience persistent fatigue along with symptoms that resemble infectious illnesses, neurological problems, and joint/muscle issues—similar to what has been reported in other countries.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Sleep apnea and psychological functioning in chronic fatigue syndrome.

Libman, Eva, Creti, Laura, Baltzan, Marcel et al.·Journal of health psychology·2009

This study looked at whether sleep apnea (a condition where breathing stops and starts during sleep) is common in people with ME/CFS and how it affects mood and psychological well-being. The researchers found that 68% of ME/CFS patients had sleep apnea, but those who did were not significantly more ill than those without it. Both the ME/CFS and sleep apnea groups showed more psychological difficulties than healthy controls, but the researchers suggest these emotional struggles are likely a natural response to living with a chronic illness rather than a separate psychiatric condition.

SleepDiagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

An evaluation of exclusionary medical/psychiatric conditions in the definition of chronic fatigue syndrome.

Jones, James F, Lin, Jin-Mann S, Maloney, Elizabeth M et al.·BMC medicine·2009

This study looked at whether people diagnosed with ME/CFS who also have other medical or psychiatric conditions (like depression or thyroid disease) are actually sicker than those with ME/CFS alone. Researchers surveyed over 5,600 people in Georgia and clinically evaluated 781 of them. They found that about one-third of people had additional conditions, but surprisingly, people with and without these extra conditions reported similar levels of fatigue and disability.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Psychiatric comorbidity in persons with chronic fatigue syndrome identified from the Georgia population.

Nater, Urs M, Lin, Jin-Mann S, Maloney, Elizabeth M et al.·Psychosomatic medicine·2009

This study looked at how often people with ME/CFS also have psychiatric conditions like depression or anxiety. Researchers called random people in Georgia and invited those who were unwell to participate. They found that 57% of people with ME/CFS had at least one current psychiatric diagnosis, compared to 45% of people with similar but milder symptoms. Importantly, most people with ME/CFS who had these psychiatric conditions hadn't seen a mental health specialist in the past 6 months.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

The doctor-patient relationship in chronic fatigue syndrome: survey of patient perspectives.

Van Hoof, Elke·Quality in primary care·2009

This study surveyed 177 ME/CFS patients about their experiences with their doctors. The researchers found that most general practitioners (GPs) do not feel confident diagnosing or treating ME/CFS, and patients often felt their doctors did not understand their condition. Poor communication and lack of GP knowledge about ME/CFS led many patients to feel unsupported and unheard in medical appointments.

Diagnostics
E2 ModeratePEM unclearModerate confidenceObservationalEditor reviewed

Chronic fatigue syndrome and related disorders in UK veterans of the Gulf War 1990-1991: results from a two-phase cohort study.

Ismail, K, Kent, K, Sherwood, R et al.·Psychological medicine·2008

This study looked at whether Gulf War veterans had higher rates of ME/CFS and related conditions compared to other military personnel. Researchers surveyed over 10,000 military personnel and then closely examined disabled Gulf War veterans and similarly disabled veterans who served elsewhere. They found that Gulf War veterans were about 8 times more likely to meet the criteria for ME/CFS than veterans who were not deployed to the Gulf.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

The awareness of chronic fatigue syndrome: a comparative study in Brazil and the United Kingdom.

Cho, Hyong Jin, Menezes, Paulo Rossi, Bhugra, Dinesh et al.·Journal of psychosomatic research·2008

This study compared how well doctors and the general public in Brazil and the United Kingdom recognize ME/CFS. Researchers found that far fewer people in Brazil were familiar with the condition compared to the UK—only 16% of Brazilian patients had heard of it, compared to 55% in Britain. Even among Brazilian specialist doctors, less than a third could identify ME/CFS from a typical case description.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

The management of children with chronic fatigue syndrome-like illness in primary care: a cross-sectional study.

Saidi, Guitta, Haines, Linda·The British journal of general practice : the journal of the Royal College of General Practitioners·2006

This study looked at how family doctors (GPs) in the UK identify and care for children and teenagers with ME/CFS-like illness in their regular clinics. Researchers reviewed medical records and patient experiences from 116 young people with severe fatigue lasting over 3 months. Most were girls around age 13, and their illness had lasted several years. The study found that GPs diagnosed about half of them with CFS/ME, often within 6 months, and referred most patients to specialists or suggested strategies like pacing and graded exercise.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Prevalence of chronic fatigue and chronic fatigue syndrome in Korea: community-based primary care study.

Kim, Cheol Hwan, Shin, Ho Cheol, Won, Chang Won·Journal of Korean medical science·2005

Researchers in Korea asked nearly 1,650 patients visiting primary care clinics about fatigue and checked whether they had chronic fatigue or ME/CFS. They found that about 8% of patients had chronic fatigue, but only 0.6% (less than 1%) had ME/CFS. Most chronic fatigue cases could be explained by physical or psychological causes, while ME/CFS cases had no clear medical explanation.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

The definition of disabling fatigue in children and adolescents.

Fowler, Tom, Duthie, Pamela, Thapar, Anita et al.·BMC family practice·2005

This study looked at how disabling fatigue in children and teens should be defined, since the current definition used for adults might not fit young people well. Researchers found that children with disabling fatigue that didn't quite meet the strict adult criteria still suffered just as much and missed just as much school as those who did meet the strict criteria. The study suggests that doctors should use a broader, less restrictive definition to catch all children who need help.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Chronic Fatigue Syndrome: a survey of GPs' attitudes and knowledge.

Bowen, Jo, Pheby, Derek, Charlett, Andre et al.·Family practice·2005

This study asked general practitioners (GPs) in the UK what they knew about ME/CFS and how confident they felt diagnosing and treating it. About half of the GPs surveyed didn't feel confident making a diagnosis, and 41% didn't feel confident treating the condition. The study found that GPs who believed ME/CFS was a real medical condition had much more positive attitudes toward patients.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCase-ControlEditor reviewed

Chronic fatigue syndrome--a clinically empirical approach to its definition and study.

Reeves, William C, Wagner, Dieter, Nisenbaum, Rosane et al.·BMC medicine·2005

This study tested two different ways of diagnosing ME/CFS to see which one worked better. Researchers in Kansas recruited 227 people—some with ME/CFS, some with unexplained fatigue that didn't meet ME/CFS criteria, some depressed, and some healthy—and admitted them to a hospital for two days of testing. They found that a new method for diagnosing ME/CFS (based on measuring fatigue severity, disability, and symptoms) worked much better at identifying truly ill people than the old method.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Chronic fatigue in a population sample: definitions and heterogeneity.

Sullivan, Patrick F, Pedersen, Nancy L, Jacks, Andreas et al.·Psychological medicine·2005

This study looked at how doctors define ME/CFS by surveying over 31,000 Swedish adults about their fatigue symptoms. The researchers found that the current official checklist for diagnosing ME/CFS (requiring 4 out of 8 specific symptoms) doesn't match how fatigue actually varies in real populations. Using statistical analysis, they identified a recognizable ME/CFS-like illness pattern, but concluded that a simpler definition focusing on severe, disabling fatigue might work better.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Primary healthcare provision and Chronic Fatigue Syndrome: a survey of patients' and General Practitioners' beliefs.

Thomas, Marie A, Smith, Andrew P·BMC family practice·2005

This study asked both ME/CFS patients and general practitioners (GPs) in Wales what they knew about ME/CFS. Researchers found that many GPs had very little specialist knowledge about the condition, and concerningly, only about half of the GPs surveyed actually believed ME/CFS was a real illness. The study suggested that creating better educational materials for both GPs and patients could help improve understanding and care.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

The prevalence of self-reported chronic fatigue in a U.S. twin registry.

Furberg, Helena, Olarte, Megan, Afari, Niloo et al.·Journal of psychosomatic research·2005

This study looked at how common fatigue-related illnesses are among twins in the United States and found that fatigue symptoms are quite common, affecting over one-third of people at some point in their lives. Women were 2-3 times more likely to report fatigue than men, and women typically experienced it at younger ages. People with chronic fatigue had significantly worse quality of life and more additional symptoms than those without fatigue.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Factors influencing the diagnosis of chronic fatigue syndrome.

Solomon, Laura, Reeves, William C·Archives of internal medicine·2004

Researchers in Wichita, Kansas identified people with ME/CFS symptoms from the general population and found that only 16% had ever been diagnosed with the condition by a doctor. People were more likely to have received a diagnosis if they had moderate income, developed fatigue suddenly, or had tender lymph nodes and sore throat. This suggests that most people with ME/CFS in the community are never formally diagnosed.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Factor analysis of symptoms among subjects with unexplained chronic fatigue: what can we learn about chronic fatigue syndrome?

Nisenbaum, Rosane, Reyes, Michele, Unger, Elizabeth R et al.·Journal of psychosomatic research·2004

This study looked at 1,391 people with unexplained chronic fatigue to understand which symptoms tend to occur together. Researchers found that ME/CFS symptoms cluster into three main groups: muscle and joint pain, infection-like symptoms, and problems with thinking, mood, and sleep. Interestingly, people with and without an ME/CFS diagnosis had significant overlap in these symptoms, suggesting that ME/CFS exists on a spectrum rather than as a completely distinct condition.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

The specificity of the CDC-1994 criteria for chronic fatigue syndrome: comparison of health status in three groups of patients who fulfill the criteria.

Kennedy, Gwen, Abbot, Neil C, Spence, Vance et al.·Annals of epidemiology·2004

This study looked at whether the standard definition of ME/CFS is specific enough to identify a single disease. Researchers compared three groups of patients who all met the official diagnostic criteria but got sick in different ways: some had gradual onset, some developed symptoms after Gulf War service, and some after pesticide exposure. They found important differences between these groups in their physical symptoms and emotional health, suggesting the current definition may be catching different conditions.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceObservationalEditor reviewed

Chronic fatigue syndrome and other fatiguing illnesses in adolescents: a population-based study.

Jones, James F, Nisenbaum, Rosane, Solomon, Laura et al.·The Journal of adolescent health : official publication of the Society for Adolescent Medicine·2004

Researchers surveyed families in Kansas to see how many adolescents (ages 12-17) had chronic fatigue syndrome (CFS) or other long-term fatigue illnesses. They found that CFS is much less common in teenagers than in adults. When both teens and their parents were carefully evaluated by doctors, none of the participating teenagers actually met the full definition of CFS, though some had prolonged fatigue from other causes.

Diagnostics
E2 ModeratePEM unclearModerate confidenceObservationalEditor reviewed

Incidence of fatigue symptoms and diagnoses presenting in UK primary care from 1990 to 2001.

Gallagher, Arlene M, Thomas, Janice M, Hamilton, William T et al.·Journal of the Royal Society of Medicine·2004

This study looked at how often fatigue and related diagnoses were recorded in UK doctor's offices between 1990 and 2001. While the overall number of fatigue diagnoses decreased, the number of people diagnosed with ME/CFS and fibromyalgia actually increased during this time. Interestingly, the number of people reporting fatigue symptoms stayed roughly the same, suggesting that doctors may have simply changed how they labeled and diagnosed these conditions rather than there being a real change in how many people were affected.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Variability in diagnostic criteria for chronic fatigue syndrome may result in substantial differences in patterns of symptoms and disability.

Jason, Leonard A, Helgerson, Jena, Torres-Harding, Susan R et al.·Evaluation & the health professions·2003

This study compared two different sets of diagnostic criteria used to identify ME/CFS: one created by Fukuda and colleagues, and another specifically for myalgic encephalomyelitis (ME). The researchers found that these two definitions identified somewhat different groups of patients, with important differences in neurological symptoms, psychiatric issues, fatigue, and joint/muscle pain. This matters because it means studies using different definitions may not be easily compared.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Comparing symptoms of chronic fatigue syndrome in a community-based versus tertiary care sample.

Jason, Leonard A, Plioplys, Audrius V, Torres-Harding, Susan et al.·Journal of health psychology·2003

This study compared ME/CFS symptoms between two groups of patients: those who sought care at major medical centers and those found in the general community. Researchers found that people being treated at tertiary care hospitals reported experiencing more symptoms than community members with ME/CFS. This suggests that the people typically studied in research may not represent all people living with ME/CFS.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

The head-up tilt test with haemodynamic instability score in diagnosing chronic fatigue syndrome.

Naschitz, J E, Rosner, I, Rozenbaum, M et al.·QJM : monthly journal of the Association of Physicians·2003

Researchers developed a simple test using a tilting table to measure how well the body controls blood pressure and heart rate in ME/CFS patients. By tilting people upright and measuring these vital signs, they found a pattern (called a haemodynamic instability score) that appeared in ME/CFS patients but not in healthy people or those with other conditions. This test could help doctors confirm an ME/CFS diagnosis with objective measurements rather than relying only on symptoms.

Autonomic Nervous SystemDiagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Differences between patients with chronic fatigue syndrome and with chronic fatigue at an infectious disease clinic in Stockholm, Sweden.

Evengård, Birgitta, Jonzon, Eva, Sandberg, Anneli et al.·Psychiatry and clinical neurosciences·2003

This study compared two groups of people with severe, long-lasting fatigue seen at an infectious disease clinic in Sweden: those who met criteria for ME/CFS and those with chronic fatigue (CF) but not ME/CFS. The main finding was that ME/CFS patients reported more physical symptoms and work disability, and most had a sudden onset following an infection, whereas CF patients had more mental health symptoms and a more gradual, burnout-like pattern. The researchers suggest these may be two different conditions with different underlying causes.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Distinguishing patients with chronic fatigue from those with chronic fatigue syndrome: a diagnostic study in UK primary care.

Darbishire, L, Ridsdale, L, Seed, P T·The British journal of general practice : the journal of the Royal College of General Practitioners·2003

This study looked at 141 people in UK doctor's offices who came in with fatigue lasting six months or longer. The researchers found that about two-thirds had chronic fatigue that didn't quite meet the official ME/CFS definition, while one-third had ME/CFS. People with ME/CFS had more severe symptoms, were more likely to be depressed and unemployed, and visited their doctor much more often than those with chronic fatigue alone.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Diagnosing chronic fatigue syndrome: comparison of a protocol and computerised questionnaires.

Prins, J B, Elving, L D, Koning, H et al.·The Netherlands journal of medicine·2003

This study looked at whether doctors and researchers using a computer questionnaire agreed on who has ME/CFS. They reviewed 516 patients with chronic fatigue and found that doctors and researchers agreed about 84% of the time. When they disagreed, it was usually because they couldn't agree on how severe the fatigue was or how much it affected daily life. Only 3% of patients had a physical medical condition that explained their fatigue.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCase-ControlEditor reviewed

Chronic fatigue in a population-based study of Gulf War veterans.

McCauley, Linda A, Joos, Sandra K, Barkhuizen, Andre et al.·Archives of environmental health·2002

Researchers studied Gulf War veterans to see how many had chronic fatigue that couldn't be explained by standard medical tests. They found that about 2.2% of veterans met the official criteria for ME/CFS, and another 5.1% had unexplained fatigue. Women veterans were more likely to have these conditions than men. Unlike some other ME/CFS patients, most of these veterans developed their fatigue gradually rather than suddenly.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCase-ControlEditor reviewed

Symptom occurrence in persons with chronic fatigue syndrome.

Jason, L A, Torres-Harding, S R, Carrico, A W et al.·Biological psychology·2002

This study compared symptoms between people with ME/CFS, people with depression, and healthy controls to understand which symptoms are specific to ME/CFS. The researchers found that certain pain symptoms (headaches, sore throat, joint and muscle pain) were common in ME/CFS but also appeared in depression. However, ME/CFS patients uniquely experienced widespread muscle weakness and various heart, lung, and nervous system symptoms that weren't seen in the other groups.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

The prevalence of chronic fatigue syndrome in Iceland - a national comparison by gender drawing on four different criteria.

Líndal, Eiríkur, Stefánsson, Jón G, Bergmann, Sverrir·Nordic journal of psychiatry·2002

This study asked over 2,500 Icelanders about symptoms of chronic fatigue syndrome (CFS) to find out how many people have it. Different diagnosis criteria gave very different results—ranging from 0% to 4.9%—showing that how doctors define CFS matters a lot. The study found that women made up most of the people with CFS, and there were some interesting differences between men and women in their symptoms.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Clinicopathological findings consistent with primary Sjögren's syndrome in a subset of patients diagnosed with chronic fatigue syndrome: preliminary observations.

Sirois, D A, Natelson, B·The Journal of rheumatology·2001

Some people with ME/CFS experience dry eyes and dry mouth, which are also common symptoms of Sjögren's syndrome, an autoimmune disorder. This study tested 25 ME/CFS patients and 18 healthy volunteers for signs of Sjögren's syndrome using eye tests, saliva gland biopsies, and blood tests. The researchers found that about one-third of the ME/CFS patients had findings consistent with primary Sjögren's syndrome, while none of the healthy volunteers did.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

What is chronic fatigue syndrome? Heterogeneity within an international multicentre study.

Wilson, A, Hickie, I, Hadzi-Pavlovic, D et al.·The Australian and New Zealand journal of psychiatry·2001

This study looked at 744 people with chronic fatigue across eight countries to see if they formed different groups based on their symptoms. Researchers found two distinct subgroups: a larger group (68%) with less severe illness and fewer psychiatric issues, and a smaller group (32%) whose symptoms looked more like somatoform illness (where psychological factors strongly influence physical symptoms). Importantly, the proportion of people in each group varied dramatically between countries (6-48%), suggesting that how doctors diagnose and classify ME/CFS is not standardized worldwide.

DiagnosticsCognitive Impairment
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Patients' perceptions of medical care in chronic fatigue syndrome.

Deale, A, Wessely, S·Social science & medicine (1982)·2001

This study asked 68 ME/CFS patients about their experiences with medical care. Two-thirds of patients were unhappy with the care they received. Patients felt most satisfied when doctors listened, showed genuine interest, and communicated clearly—not necessarily when doctors could cure the illness. Patients were most frustrated when doctors were dismissive, confused about ME/CFS, or gave conflicting advice.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

A definition-based analysis of symptoms in a large cohort of patients with chronic fatigue syndrome.

De Becker, P, McGregor, N, De Meirleir, K·Journal of internal medicine·2001

This study looked at 2,073 patients with chronic fatigue to understand how well two common diagnostic criteria (Fukuda and Holmes) identify ME/CFS. The researchers found that the Holmes criteria selected patients with more severe symptoms, while the Fukuda criteria included a broader group with milder cases. Adding or removing certain symptoms from the current diagnostic criteria could help doctors better identify who truly has ME/CFS.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceMethods-PaperEditor reviewed

Screening for prolonged fatigue syndromes: validation of the SOFA scale.

Hadzi-Pavlovic, D, Hickie, I B, Wilson, A J et al.·Social psychiatry and psychiatric epidemiology·2000

This study developed and tested two screening tools (called SOFA/CFS and SOFA/GP) to help doctors identify patients with chronic fatigue syndrome and prolonged fatigue conditions. Researchers tested these tools with 770 CFS patients in specialist clinics and 1,593 people in regular primary care settings, and found that both instruments could reliably spot these fatigue syndromes. The study also showed that fatigue syndromes have distinct patterns that are separate from anxiety and depression, and these patterns remained stable over a 12-month follow-up.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Diagnosis of psychiatric disorder in clinical evaluation of chronic fatigue syndrome.

Deale, A, Wessely, S·Journal of the Royal Society of Medicine·2000

This study looked at how often ME/CFS patients are incorrectly diagnosed with psychiatric conditions like depression. Researchers found that about two-thirds of patients who had been labeled with a psychiatric diagnosis actually didn't have one, while about one-third of patients without a psychiatric diagnosis did have a treatable mental health condition. The study shows that distinguishing between ME/CFS and psychiatric disorders can be difficult, and doctors need better tools and training to get the diagnosis right.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

General practitioners' beliefs, attitudes and reported actions towards chronic fatigue syndrome.

Steven, I D, McGrath, B, Qureshi, F et al.·Australian family physician·2000

This study surveyed Australian doctors about what they think and do regarding ME/CFS. Most doctors who diagnose ME/CFS agreed on six key symptoms, including long-lasting fatigue that doesn't improve with rest and exhaustion after minor activity. However, nearly one-third of doctors didn't believe ME/CFS was a real condition and thought depression was the actual cause instead.

Diagnostics
E2 ModeratePEM unclearPreliminaryCross-SectionalEditor reviewed

Chronic Fatigue Syndrome and Primary Fibromyalgia Syndrome as recognized by GPs.

Bazelmans, E, Vercoulen, J H, Swanink, C M et al.·Family practice·1999

This Dutch study surveyed general practitioners (GPs) to understand how often they see patients with chronic fatigue syndrome (CFS) and fibromyalgia syndrome (FMS) in their practices. About 60% of GPs responded, and most reported seeing patients with these conditions. The study estimated that roughly 112 out of every 100,000 people have CFS and 157 have FMS, though these numbers are likely underestimates since some cases may go unrecognized.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Idiopathic chronic fatigue and chronic fatigue syndrome: a comparison of two case-definitions.

Arpino, C, Carrieri, M P, Valesini, G et al.·Annali dell'Istituto superiore di sanita·1999

This study compared how many patients were diagnosed with ME/CFS using two different diagnostic definitions from 1988 and 1994. The researchers found that the 1994 definition diagnosed more patients as having CFS, but these additional patients were less likely to have had a sudden onset of illness or signs suggesting an infectious trigger like fever or sore throat. This suggests the two definitions captured somewhat different groups of people.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

A community-based study of chronic fatigue syndrome.

Jason, L A, Richman, J A, Rademaker, A W et al.·Archives of internal medicine·1999

Researchers in Chicago called nearly 29,000 adults to find out how many people have ME/CFS. They found that about 0.42% of the general population has the condition—roughly 1 in 240 people. The study showed that ME/CFS affects women, minority groups, and people with lower education levels more often than previously thought, challenging the old idea that it mainly affected white middle-class people.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Prevalence of chronic fatigue syndrome in a community population in Japan.

Kawakami, N, Iwata, N, Fujihara, S et al.·The Tohoku journal of experimental medicine·1998

This Japanese study looked at how common ME/CFS is in everyday communities by interviewing 137 people. Researchers found that about 1 in 67 people had severe, persistent fatigue that met ME/CFS criteria and significantly disrupted their daily life. The findings suggested ME/CFS might be more common in Japan than in Western countries studied previously.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Chronic fatigue syndrome criteria in patients with other forms of unexplained chronic fatigue.

Chester, A C·Journal of psychiatric research·1997

This study looked at nearly 300 young people to see how many had symptoms similar to ME/CFS even though they didn't have a confirmed ME/CFS diagnosis. The researchers found that people with unexplained chronic fatigue shared many symptoms with ME/CFS patients, including fever, sore lymph nodes, muscle weakness, muscle pain, headaches, joint pain, brain fog, and sleep problems. This suggests that ME/CFS symptoms are common in people with other types of long-lasting, unexplained tiredness.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCase-ControlEditor reviewed

Fatiguing illness among employees in three large state office buildings, California, 1993: was there an outbreak?

Shefer, A, Dobbins, J G, Fukuda, K et al.·Journal of psychiatric research·1997

Researchers surveyed over 3,300 state office workers in California to see if there was an unusual outbreak of long-lasting fatigue or ME/CFS-like illness. They found that about 18% of workers reported fatigue lasting at least a month, but this rate was similar in buildings thought to have clusters and in a comparison building, suggesting there was no outbreak. The study identified that certain groups—including women, Hispanic workers, Native American workers, and those with lower income or education—were more likely to report fatigue.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceObservationalEditor reviewed

Surveillance for chronic fatigue syndrome--four U.S. cities, September 1989 through August 1993.

Reyes, M, Gary, H E, Dobbins, J G et al.·MMWR. CDC surveillance summaries : Morbidity and mortality weekly report. CDC surveillance summaries·1997

Between 1989 and 1993, researchers in four U.S. cities tracked patients with chronic fatigue syndrome (CFS) to understand how common it was and what it looked like. Of 565 patients evaluated, 130 met the CFS criteria. The study found that CFS affected about 4 to 9 people per 100,000 in the general population, but was much more common in white women. Most CFS patients were in their 30s when they got sick and had been ill for about 7 years.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

'Seronegative' Sjögren's syndrome manifested as a subset of chronic fatigue syndrome.

Nishikai, M, Akiya, K, Tojo, T et al.·British journal of rheumatology·1996

This study looked at whether some people diagnosed with ME/CFS who also experience dry eyes and mouth might actually have a related condition called Sjögren's syndrome. Researchers tested one-third of ME/CFS patients with these dry symptoms against several official diagnostic criteria for Sjögren's syndrome and found they met the criteria. However, these patients tested negative for the antibodies typically found in Sjögren's syndrome, making them an unusual variant of the disease.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Assessing somatization disorder in the chronic fatigue syndrome.

Johnson, S K, DeLuca, J, Natelson, B H·Psychosomatic medicine·1996

This study compared how often doctors diagnosed somatization disorder (a condition where emotional distress causes physical symptoms) in ME/CFS patients versus people with multiple sclerosis, depression, or no illness. The researchers found that whether symptoms were labeled as 'psychiatric' or 'physical' dramatically changed the diagnosis rate, suggesting that labeling is somewhat arbitrary in ME/CFS. Very few patients in any group actually met strict diagnostic criteria for somatization disorder.

Diagnostics
E2 ModeratePEM unclearPreliminaryObservationalEditor reviewed

'Too tired to go to the support group': a health needs assessment of myalgic encephalomyelitis.

Sutton, G C·Journal of public health medicine·1996

This 1996 study examined what healthcare services people with ME actually need in one English region. Researchers found that ME patients wanted four main things: a clear medical diagnosis, time to rest, specific treatments, and social support. However, the study found that there was no agreement among doctors and experts about what ME is, making it very difficult for the health system to plan appropriate care.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Functional status in patients with chronic fatigue syndrome, other fatiguing illnesses, and healthy individuals.

Buchwald, D, Pearlman, T, Umali, J et al.·The American journal of medicine·1996

This study used a health survey (SF-36) to measure how much ME/CFS affects daily activities in 185 patients, comparing them to people with other illnesses and healthy controls. ME/CFS patients had the lowest scores, meaning the most disability, especially in physical activities, work, and pain. The survey was useful for showing that ME/CFS causes more functional impairment than other conditions like depression or infectious mononucleosis.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Estimating rates of chronic fatigue syndrome from a community-based sample: a pilot study.

Jason, L A, Taylor, R, Wagner, L et al.·American journal of community psychology·1995

This study looked at how many people in the general community have ME/CFS by calling over 1,000 randomly selected households by telephone. Instead of relying on patients referred by doctors (which may miss people who can't afford care or distrust doctors), the researchers directly asked community members about their symptoms. They found that ME/CFS may be more common than previously thought, affecting about 0.2% of the population.

Diagnostics
E2 ModeratePEM unclearModerate confidenceObservationalEditor reviewed

Can the chronic fatigue syndrome be defined by distinct clinical features?

Hickie, I, Lloyd, A, Hadzi-Pavlovic, D et al.·Psychological medicine·1995

This study examined whether all people diagnosed with ME/CFS have the same illness or whether they actually have different types. Researchers analyzed symptoms from 565 patients and found that ME/CFS is not one uniform condition—instead, they identified two distinct patient groups with different symptom patterns, illness duration, and recovery rates.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceObservationalEditor reviewed

Chronic fatigue and the chronic fatigue syndrome: prevalence in a Pacific Northwest health care system.

Buchwald, D, Umali, P, Umali, J et al.·Annals of internal medicine·1995

This study surveyed over 3,000 people in a Seattle health plan to find out how common ME/CFS and chronic fatigue are in the community. Researchers found that about 19% of people reported chronic fatigue, but only a tiny fraction actually met the strict diagnostic criteria for ME/CFS. Those with ME/CFS or chronic fatigue had worse physical health, more difficulty with daily activities, and more emotional stress compared to healthy people without fatigue.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceObservationalEditor reviewed

Diagnosis in chronic illness: disabling or enabling--the case of chronic fatigue syndrome.

Woodward, R V, Broom, D H, Legge, D G·Journal of the Royal Society of Medicine·1995

This study looked at whether giving someone a CFS diagnosis helps or hurts them. Researchers interviewed 20 doctors and 50 CFS patients over 2 years. Most doctors were reluctant to diagnose CFS because they worried it might make patients feel worse, but patients actually found the diagnosis helpful because it finally explained what was wrong with them.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceLongitudinalEditor reviewed

Neuraesthenia revisited: ICD-10 and DSM-III-R psychiatric syndromes in chronic fatigue patients and comparison subjects.

Farmer, A, Jones, I, Hillier, J et al.·The British journal of psychiatry : the journal of mental science·1995

This study examined psychiatric conditions in people with chronic fatigue syndrome (CFS) using standardized diagnostic interviews. Most CFS patients met criteria for a condition called neuraesthenia (an older term for nerve exhaustion) and had higher rates of depression, anxiety, and sleep problems compared to healthy people. Interestingly, when researchers followed patients over about 11 months without giving specific treatment, some psychiatric symptoms improved on their own, while the core fatigue condition remained.

SleepDiagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

A comparison of case definitions of chronic fatigue syndrome.

Bates, D W, Buchwald, D, Lee, J et al.·Clinical infectious diseases : an official publication of the Infectious Diseases Society of America·1994

This study tested whether three different sets of diagnostic criteria for ME/CFS identified the same patients. Researchers looked at 805 patients at two clinics and found that about 55-61% met each of the three definitions, though different patients sometimes qualified under different criteria. The study suggests that using broader, more flexible definitions might better capture people with ME/CFS.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Prevalence of chronic fatigue syndrome in Italian patients with persistent fatigue.

Conti, F, Priori, R, De Petrillo, G et al.·Annali italiani di medicina interna : organo ufficiale della Societa italiana di medicina interna·1994

Researchers in Rome studied 63 patients with persistent fatigue lasting at least 6 months to see how many actually had ME/CFS. They found that only 6 patients (about 10%) met the official diagnostic criteria for ME/CFS, while 37 patients (59%) had other medical conditions explaining their fatigue, such as infections or other illnesses. This suggests that ME/CFS is relatively uncommon as a cause of severe fatigue compared to other treatable conditions.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Prevalence of chronic fatigue syndrome-related symptoms among nurses.

Jason, L A, Taylor, S L, Johnson, S et al.·Evaluation & the health professions·1993

This study looked at how common ME/CFS-related symptoms are among nurses. Researchers surveyed a group of nurses and found that when using different definitions of the illness, more nurses showed signs of ME/CFS than had been found in previous studies of the general population. This was the first study to specifically examine ME/CFS in healthcare workers.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCase-ControlEditor reviewed

A controlled study of brain magnetic resonance imaging in patients with the chronic fatigue syndrome.

Natelson, B H, Cohen, J M, Brassloff, I et al.·Journal of the neurological sciences·1993

Researchers compared brain scans (MRIs) of 52 people with ME/CFS to 52 similar healthy people. They found that ME/CFS patients were much more likely to have abnormal brain scans—27% compared to only 2% in the control group. The abnormalities included areas of white matter changes and some brain tissue enlargement, though the researchers noted that some of these findings might actually indicate other medical conditions rather than ME/CFS itself.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Chronic fatigue and chronic fatigue syndrome: clinical epidemiology and aetiological classification.

Manu, P, Lane, T J, Matthews, D A·Ciba Foundation symposium·1993

This study looked at 405 patients who came to a hospital complaining of chronic fatigue and tried to figure out what was causing it. Doctors found that most patients had psychiatric conditions like depression or anxiety rather than physical diseases. About 30% of patients met the definition for ME/CFS, and these patients were more likely to attribute their illness to a viral infection than other fatigued patients.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceObservationalEditor reviewed

Epidemiology of chronic fatigue syndrome: the Centers for Disease Control Study.

Gunn, W J, Connell, D B, Randall, B·Ciba Foundation symposium·1993

Between 1989 and 1991, the CDC tracked patients with chronic fatigue syndrome across four U.S. cities to understand how common the illness is and who gets it. Researchers found that only about 1 in 4 patients referred to them actually met the strict diagnostic criteria for CFS, while others had different medical conditions or psychiatric histories that might explain their fatigue. The study estimated that CFS affects roughly 2–11 people per 100,000 in the general population, and it most commonly affected women in their 30s.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Prevalence of fatigue and chronic fatigue syndrome in a primary care practice.

Bates, D W, Schmitt, W, Buchwald, D et al.·Archives of internal medicine·1993

This study looked at how common severe, long-lasting fatigue is in a primary care doctor's office and how often it is ME/CFS. Researchers found that while about 27% of patients had long-term fatigue affecting their daily life, most could be explained by other medical or mental health conditions. Only about 0.3% to 1% of patients actually had ME/CFS, depending on which diagnostic criteria were used.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Estimating the prevalence of chronic fatigue syndrome and associated symptoms in the community.

Price, R K, North, C S, Wessely, S et al.·Public health reports (Washington, D.C. : 1974)·1992

This study looked at how common chronic fatigue syndrome (CFS) is in the general population by surveying over 13,500 people between 1981 and 1984. Researchers found that while about 23% of people reported experiencing persistent fatigue at some point in their lives, actual CFS meeting strict diagnostic criteria was extremely rare—only 1 person in the entire study group had the condition. When researchers excluded people with other medical or psychiatric illnesses, CFS became even rarer.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Chronic fatigue syndrome criteria. A critique of the requirement for multiple physical complaints.

Katon, W, Russo, J·Archives of internal medicine·1992

This study looked at 285 people with chronic fatigue to understand whether having many physical symptoms was linked to psychiatric conditions like depression and anxiety. Researchers found that patients reporting more unexplained physical symptoms were significantly more likely to have current or past psychiatric diagnoses. The authors suggest that ME/CFS diagnostic criteria should be changed to include people with fatigue and few physical symptoms, and potentially exclude those with many physical complaints.

Diagnostics
E2 ModeratePEM not requiredPreliminaryObservationalEditor reviewed

Clinical, epidemiologic, and virologic studies in four clusters of the chronic fatigue syndrome.

Levine, P H, Jacobson, S, Pocinki, A G et al.·Archives of internal medicine·1992

Researchers studied four different outbreaks of ME/CFS in the Nevada-California region over 3 years, following patients through interviews and blood tests to look for viral causes. They found that almost all patients recovered and returned to their normal activities within the 3-year period. The viruses they tested for—including Epstein-Barr virus and others—were not responsible for the illness, though one outbreak may have been triggered by a parasite called giardia.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Psychiatric illness in patients with chronic fatigue and those with rheumatoid arthritis.

Katon, W J, Buchwald, D S, Simon, G E et al.·Journal of general internal medicine·1991

This study compared people with chronic fatigue to people with rheumatoid arthritis to understand psychiatric differences between the groups. Researchers found that people with chronic fatigue had higher rates of depression and other mental health conditions than people with rheumatoid arthritis. Interestingly, when they looked specifically at patients who met strict CDC criteria for CFS, these patients were not noticeably different from those with chronic fatigue who didn't meet the criteria.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Prevalence of chronic fatigue syndrome in an Australian population.

Lloyd, A R, Hickie, I, Boughton, C R et al.·The Medical journal of Australia·1990

This Australian study estimated how common ME/CFS is in the community by looking for cases in a town of 114,000 people. Researchers found about 37 cases per 100,000 people, mostly affecting young adults of both sexes. The illness caused serious problems for patients, with nearly half unable to work or attend school.

Diagnostics
E2 ModeratePEM unclearPreliminaryObservationalEditor reviewed

Diagnosing myalgic encephalomyelitis.

Zala, J·The Practitioner·1989

This study looked at how doctors can diagnose ME/CFS, especially when standard blood tests don't show clear evidence of infection. Researchers compared patients who had lab evidence of infection with those who didn't, and discussed what doctors should look for to make a reliable diagnosis based on symptoms and clinical presentation alone.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Psychiatric diagnoses in patients who have chronic fatigue syndrome.

Kruesi, M J, Dale, J, Straus, S E·The Journal of clinical psychiatry·1989

This study looked at 28 patients with ME/CFS to see how often they had been diagnosed with psychiatric conditions like depression. The researchers found that psychiatric diagnoses were common in this group. Importantly, when they reviewed medical records, they discovered that most of these psychiatric conditions had started before the ME/CFS illness began, not after.

Diagnostics
E2 ModeratePEM not requiredPreliminaryObservationalEditor reviewed

The frequency of the chronic fatigue syndrome in patients with symptoms of persistent fatigue.

Manu, P, Lane, T J, Matthews, D A·Annals of internal medicine·1988

This study looked at 135 people with severe fatigue lasting at least 6 months to see how many actually had ME/CFS. The researchers found that only 6 patients (about 4%) met the criteria for ME/CFS, while most of the others had psychiatric conditions like depression or anxiety that were causing their fatigue. This suggests that ME/CFS is quite rare among people presenting with fatigue symptoms.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Who receives a diagnostic label for fibromyalgia, chronic fatigue syndrome, and irritable bowel syndrome? A study in the lifelines cohort.

Tattan, Mais, Hanssen, Denise J C, Rosmalen, Judith G M·Journal of psychosomatic research·2026

This study looked at over 150,000 people to understand why some people with ME/CFS, fibromyalgia, or irritable bowel syndrome receive a diagnosis while others with the same symptoms do not. The researchers found that only a small number of people who meet the criteria for these conditions actually get diagnosed—about 14% for ME/CFS. Several factors like sex, education level, other health conditions, and how often people visit doctors affected whether they received a diagnosis.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

The Diagnostic Journey of Dysautonomia Patients: Insights from a Patient-Reported Outcome Study.

O'Dell, John A, Walker, Ash, Latham, Andrew J et al.·Journal of patient experience·2025

This study followed 672 adults with dysautonomia (a condition where the nervous system that controls automatic body functions doesn't work properly) to understand how long it takes to get diagnosed and which doctors help with diagnosis. On average, it took 7.7 years for people to receive a diagnosis, and they often saw multiple types of doctors before getting answers. The study found that dysautonomia commonly occurs alongside other conditions like Ehlers-Danlos syndrome, mast cell disorders, and ME/CFS, which can make diagnosis even more confusing.

Autonomic Nervous SystemDiagnostics
E2 ModeratePEM unclearPreliminaryObservationalEditor reviewed

Assessing the influence of lived-experience experts on healthcare providers in a virtual community of practice: a qualitative study.

Weaver, Stephanie Sargent, Carry, Monique, Bertolli, Jeanne et al.·Frontiers in health services·2025

This study looked at whether having patients with lived experience of Long COVID and ME/CFS help teach doctors made a real difference in patient care. Researchers tracked what these patient-experts recommended to doctors through online training sessions from 2022-2024, and then asked actual patients if their doctors seemed to apply that advice. The main recommendations focused on validating patients' experiences, showing empathy, helping with referrals, and supporting self-care. Patients reported noticing positive changes in how their doctors treated them, suggesting that including patient-experts in medical education actually works.

Diagnostics
E2 ModeratePEM unclearPreliminaryObservationalEditor reviewed

Chronicity rhetoric in health and welfare systems inhibits patient recovery: a qualitative, ethnographic study of fibromyalgia care.

Cupit, Caroline, Finlay, Teresa, Pope, Catherine et al.·Social science & medicine (1982)·2025

This study looked at how healthcare and welfare systems talk about fibromyalgia and similar long-term conditions like ME/CFS. Researchers found that when doctors and officials constantly describe these conditions as permanent and unchangeable ('chronicity rhetoric'), it can actually get in the way of patients healing and recovering. The study suggests that changing how we talk about these conditions—and how our support systems are designed—might help patients feel more hopeful and do better.

Diagnostics
E2 ModeratePEM requiredModerate confidenceCross-SectionalEditor reviewed

Illness presentation and quality of life in myalgic encephalomyelitis/chronic fatigue syndrome and post COVID-19 condition: a pilot Australian cross-sectional study.

Weigel, Breanna, Eaton-Fitch, Natalie, Thapaliya, Kiran et al.·Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation·2024

This study compared symptoms and quality of life in people with ME/CFS, people with long COVID, and healthy controls in Australia. Both ME/CFS and long COVID patients experienced similar debilitating symptoms affecting memory, sleep, and physical function, and both groups had much lower quality of life scores than healthy people. The findings suggest that ME/CFS and long COVID are similarly serious illnesses that require comprehensive medical care.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Psychometric evaluation of the DePaul Symptom Questionnaire-Short Form (DSQ-SF) among adults with Long COVID, ME/CFS, and healthy controls: A machine learning approach.

McGarrigle, William J, Furst, Jacob, Jason, Leonard A·Journal of health psychology·2024

Researchers tested whether a symptom questionnaire called the DSQ-SF can accurately identify and distinguish between Long COVID, ME/CFS, and healthy people. Using computer algorithms to analyze the results, they found the questionnaire works well at telling these groups apart and identified which specific symptoms are most helpful for telling Long COVID and ME/CFS apart from each other and from normal health.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Factors associated with having previously received a diagnosis of fibromyalgia, chronic fatigue syndrome and irritable bowel syndrome: A cross sectional DanFunD study.

Tattan, Mais, Ørnbøl, Eva, Wellnitz, Kaare Bro et al.·Journal of psychosomatic research·2024

This study looked at 1,704 people with symptoms of functional somatic disorders (including ME/CFS, fibromyalgia, and irritable bowel syndrome) to understand who had received a diagnosis from a doctor. The researchers found that people—especially women—who had poor quality of life and negative beliefs about their illness were more likely to have received an official diagnosis. The study suggests that factors beyond just having symptoms affect whether people get diagnosed with these conditions.

Diagnostics
E2 ModeratePEM requiredModerate confidenceLongitudinalEditor reviewed

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome After SARS-CoV-2 Infection.

Unger, Elizabeth R, Lin, Jin-Mann S, Wisk, Lauren E et al.·JAMA network open·2024

This study followed over 4,300 people for up to 12 months to see whether COVID-19 infection caused ME/CFS-like symptoms. Researchers found that about 3-4% of people reported ME/CFS-like symptoms after their acute illness, but this rate was similar whether they had tested positive or negative for COVID-19. The results suggest that while some people do develop long-lasting symptoms after illness, COVID-19 may not be uniquely causing ME/CFS more often than other infections.

DiagnosticsLong COVID Overlap
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Validity and diagnostic overlap of functional somatic syndrome diagnoses.

van der Meulen, Monica L, Bos, Martje, Bakker, Stephan J L et al.·Journal of psychosomatic research·2024

This study looked at how often three common conditions—ME/CFS, fibromyalgia, and irritable bowel syndrome—occur together in the general population. Researchers surveyed nearly 90,000 people and found that these conditions overlap far more often than would happen by pure chance, especially when they last longer and cause more serious symptoms. This suggests these conditions may share common underlying features.

Diagnostics
E2 ModeratePEM unclearPreliminaryCross-SectionalEditor reviewed

Developing a Blood Cell-Based Diagnostic Test for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Using Peripheral Blood Mononuclear Cells.

Xu, Jiabao, Lodge, Tiffany, Kingdon, Caroline et al.·Advanced science (Weinheim, Baden-Wurttemberg, Germany)·2023

Researchers used a new technology called Raman spectroscopy combined with artificial intelligence to analyze blood cells from ME/CFS patients and healthy people. The test was able to correctly identify ME/CFS patients about 91% of the time and could even distinguish between mild, moderate, and severe cases with 84% accuracy. This could eventually help doctors diagnose ME/CFS with a simple blood test instead of relying only on patient symptoms.

Diagnostics
E2 ModeratePEM requiredPreliminaryCross-SectionalEditor reviewed

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and COVID-19: is there a connection?

AlMuhaissen, Suha, Abu Libdeh, Amal, ElKhatib, Yara et al.·Current medical research and opinion·2023

This study looked at whether people who had COVID-19 might develop ME/CFS afterward. Researchers asked 437 people who had COVID-19 questions based on the official diagnostic criteria for ME/CFS. They found that about 8% of COVID-19 patients met the criteria for ME/CFS, suggesting there may be a connection between the two illnesses.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceEditor reviewed

Health outcomes of sensory hypersensitivities in myalgic encephalomyelitis/chronic fatigue syndrome and multiple sclerosis.

Maeda, Kensei I, Islam, Mohammed F, Conroy, Karl E et al.·Psychology, health & medicine·2023

This study looked at how common sensitivity to light and sound are in people with ME/CFS compared to people with multiple sclerosis (MS). Researchers surveyed over 2,200 people and found that people with ME/CFS experience these sensitivities much more often than people with MS. People who had both light and sound sensitivity reported feeling worse overall than those without these sensitivities.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Orthostatic Challenge Causes Distinctive Symptomatic, Hemodynamic and Cognitive Responses in Long COVID and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Vernon, Suzanne D, Funk, Sherlyn, Bateman, Lucinda et al.·Frontiers in medicine·2022

Researchers tested whether a simple 10-minute standing test (NASA Lean Test) could reveal problems in people with Long COVID and ME/CFS. The test made symptoms worse in both patient groups but not in healthy people, and caused measurable changes in blood pressure and thinking speed. This suggests the test could help doctors confirm what patients are experiencing and provide objective evidence of their condition.

Autonomic Nervous SystemDiagnosticsCognitive Impairment
E2 ModeratePEM unclearModerate confidenceObservationalEditor reviewed

Beyond bones: The relevance of variants of connective tissue (hypermobility) to fibromyalgia, ME/CFS and controversies surrounding diagnostic classification: an observational study.

Eccles, Jessica A, Thompson, Beth, Themelis, Kristy et al.·Clinical medicine (London, England)·2021

This study looked at whether joint hypermobility (unusual flexibility and loose joints) is connected to fibromyalgia and ME/CFS. Researchers found that most patients with these conditions also had signs of hypermobility, and that higher hypermobility scores matched with worse symptoms. The results suggest that hypermobility is often missed in diagnosis, even though it significantly affects how sick people feel.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Exploratory study into the relationship between the symptoms of chronic fatigue syndrome (CFS)/myalgic encephalomyelitis (ME) and fibromyalgia (FM) using a quasiexperimental design.

Mckay, Pamela G, Walker, Helen, Martin, Colin R et al.·BMJ open·2021

This study compared people diagnosed with ME/CFS to people diagnosed with fibromyalgia to see if their symptoms were actually similar. The researchers found that both groups experienced pain, fatigue, sleep problems, and impacts on quality of life in very similar ways, suggesting these conditions may share common symptom patterns. The findings suggest that how these conditions are currently diagnosed and treated might need to be reconsidered since patients experience their symptoms so similarly.

Diagnostics
E2 ModeratePEM unclearPreliminaryObservationalEditor reviewed

Shadow Burden of Undiagnosed Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) on Society: Retrospective and Prospective-In Light of COVID-19.

Araja, Diana, Berkis, Uldis, Lunga, Asja et al.·Journal of clinical medicine·2021

This study examined how many people in Latvia may have ME/CFS symptoms but have never received a diagnosis, and investigated whether COVID-19 might cause similar long-term problems. Researchers compared symptom reports from diagnosed ME/CFS patients with undiagnosed people experiencing similar symptoms, and also tracked people who had recovered from COVID-19. The research found that undiagnosed patients face a significant financial burden on the healthcare system and themselves, and that COVID-19 can trigger ME/CFS-like symptoms in some people.

DiagnosticsLong COVID Overlap
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

The unifying diagnostic construct of bodily distress syndrome (BDS) was confirmed in the general population.

Petersen, Marie Weinreich, Schröder, Andreas, Jørgensen, Torben et al.·Journal of psychosomatic research·2020

This study looked at whether a diagnostic framework called Bodily Distress Syndrome (BDS) can help organize the overlapping symptoms seen in conditions like ME/CFS, fibromyalgia, and irritable bowel syndrome. Researchers interviewed nearly 1,600 people from the general population about their symptoms and found that symptoms naturally grouped into four clusters (heart/lung, stomach, muscle/joint, and general fatigue symptoms). The BDS framework successfully categorized people based on how many symptom clusters they experienced, suggesting it could be a useful way to diagnose and understand these complex multi-system conditions.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Systemic Hyperalgesia in Females with Gulf War Illness, Chronic Fatigue Syndrome and Fibromyalgia.

Surian, Amber A, Baraniuk, James N·Scientific reports·2020

This study measured how sensitive to pain women with ME/CFS, Gulf War Illness, and fibromyalgia are compared to healthy controls. Researchers used a tool called a dolorimeter to apply pressure to 18 specific body points and measured how much pressure it took before women felt pain. Women with these illnesses felt pain at much lower pressure levels than healthy women, showing they have widespread increased pain sensitivity.

Pain and SensitizationDiagnostics
E2 ModeratePEM requiredModerate confidenceCross-SectionalEditor reviewed

Chronic Widespread Pain in a tertiary pain clinic: classification overlap and use of a patient generated quality of life instrument.

Tschudi-Madsen, Hedda, Rødevand, Linn N, Bøymo Kaarbø, Mette et al.·Scandinavian journal of pain·2019

This study looked at 33 patients with widespread pain to understand how different diagnostic labels (fibromyalgia, chronic fatigue syndrome, and bodily distress syndrome) overlap and apply to the same people. Researchers also tested whether a patient-created quality-of-life survey could capture things that standard questionnaires miss. They found that most patients had very low quality of life scores, and that the newer diagnostic criteria for fibromyalgia work better together than older versions.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Performance of the American College of Rheumatology 2016 criteria for fibromyalgia in a referral care setting.

Ahmed, Sakir, Aggarwal, Amita, Lawrence, Able·Rheumatology international·2019

This study tested how well the 2016 fibromyalgia diagnostic criteria work in hospital specialty clinics, where patients often have multiple conditions. Researchers found that the newer criteria identified some patients that an experienced doctor using older criteria would not have diagnosed, and these patients were more likely to also have other conditions like restless leg syndrome, PTSD, or chronic fatigue syndrome. The 2016 criteria performed reasonably well, but doctors should be aware they may be catching patients with overlapping conditions rather than pure fibromyalgia.

Diagnostics
E2 ModeratePEM not requiredPreliminaryEditor reviewed

Cohort description: The Danish study of Functional Disorders.

Dantoft, Thomas Meinertz, Ebstrup, Jeanette Frost, Linneberg, Allan et al.·Clinical epidemiology·2017

This Danish study looked at nearly 10,000 people from the general population to understand functional somatic syndromes—illnesses like chronic fatigue syndrome, fibromyalgia, and irritable bowel syndrome that cause real suffering but don't show up as traditional diseases on standard medical tests. Researchers collected detailed information about symptoms, health history, lifestyle, and physical fitness, plus blood and other biological samples. The goal was to figure out how common these conditions are, what causes them, and how they affect people's lives.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

What is in a name? Comparing diagnostic criteria for chronic fatigue syndrome with or without fibromyalgia.

Meeus, Mira, Ickmans, Kelly, Struyf, Filip et al.·Clinical rheumatology·2016

This study compared people with ME/CFS to people with multiple sclerosis and healthy volunteers to see how sick they were and how well they could function. Researchers found that people with ME/CFS had worse physical abilities (like muscle strength and recovery), more severe symptoms, lower quality of life, and more difficulty with daily activities. They also discovered that when ME/CFS patients also had fibromyalgia (widespread pain), their overall symptom burden was much greater.

DiagnosticsCognitive Impairment
E2 ModeratePEM unclearModerate confidenceObservationalEditor reviewed

Investigation of suspected chronic fatigue syndrome/myalgic encephalopathy.

Owe, Jone Furlund, Næss, Halvor, Gjerde, Ivar Otto et al.·Tidsskrift for den Norske laegeforening : tidsskrift for praktisk medicin, ny raekke·2016

This study looked at 365 people who came to a hospital's neurology department because they thought they might have ME/CFS. The doctors found that only about 13% actually had ME/CFS, while nearly half of the patients had mental health or stress-related conditions instead. The study highlights how important it is for doctors to do thorough checks before deciding someone has ME/CFS, since other treatable conditions can cause similar fatigue symptoms.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Characteristics of patients contacting a center for undiagnosed and rare diseases.

Mueller, Tobias, Jerrentrup, Andreas, Bauer, Max Jakob et al.·Orphanet journal of rare diseases·2016

This study looked at 522 adults who visited a hospital center for help with diseases that hadn't been diagnosed yet. Most patients were women, and their main complaints were general weakness, joint pain, and stomach discomfort. The researchers found that many patients had been given diagnoses like chronic fatigue syndrome, fibromyalgia, or irritable bowel syndrome—conditions where symptoms are real but hard to explain with standard medical tests.

Diagnostics
E2 ModeratePEM unclearPreliminaryCross-SectionalEditor reviewed

Traditional Chinese medicine and new concepts of predictive, preventive and personalized medicine in diagnosis and treatment of suboptimal health.

Wang, Wei, Russell, Alyce, Yan, Yuxiang et al.·The EPMA journal·2014

This study looked at how to identify people in the early stages of health problems before they develop into serious diseases. The researchers created a simple 25-question survey to measure 'suboptimal health'—a state where people feel unwell with fatigue and other complaints but don't have a clear diagnosis. They tested this survey with over 3,400 people in China and found that answers to the survey were connected to blood pressure, blood sugar, and cholesterol levels.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Characterization of fatigue states in medicine and psychiatry by structured interview.

Bennett, Barbara Kaye, Goldstein, David, Chen, Michelle et al.·Psychosomatic medicine·2014

This study developed and tested a structured interview tool to help doctors better distinguish between different types of fatigue, including ME/CFS, fatigue after cancer treatment, and depression-related fatigue. Researchers interviewed women with different fatigue conditions and found the tool was very accurate at identifying ME/CFS and depression, though less reliable for cancer-related fatigue. The tool may help doctors more accurately diagnose why patients are experiencing fatigue.

DiagnosticsCognitive Impairment
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Functional somatic syndromes: sensitivities and specificities of self-reports of physician diagnosis.

Warren, John W, Clauw, Daniel J·Psychosomatic medicine·2012

This study found that when doctors ask patients "Have you been diagnosed with ME/CFS or fibromyalgia?" they miss many people who actually have these conditions based on their symptoms. For example, doctors missed 90% of people who truly had ME/CFS by symptom criteria, and 77% of those with fibromyalgia. The researchers showed that asking about symptoms directly, rather than relying on patients to report a doctor's diagnosis, is much more accurate for identifying these conditions.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

One single diagnosis, bodily distress syndrome, succeeded to capture 10 diagnostic categories of functional somatic syndromes and somatoform disorders.

Fink, Per, Schröder, Andreas·Journal of psychosomatic research·2010

This study looked at whether a new diagnosis called 'bodily distress syndrome' could capture several different conditions that cause physical symptoms not explained by standard medical tests—including ME/CFS, fibromyalgia, and irritable bowel syndrome. Researchers tested nearly 1,000 patients and found that bodily distress syndrome successfully identified 95% of patients across all these different diagnoses, suggesting these conditions might be better understood as variations of one underlying problem rather than completely separate diseases.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Dry eyes and mouth syndrome--a subgroup of patients presenting with sicca symptoms.

Price, E J, Venables, P J W·Rheumatology (Oxford, England)·2002

This study looked at 34 patients who had dry eyes and dry mouth symptoms but did not meet the standard criteria for Sjögren's syndrome. These patients had many symptoms on questionnaires but few objective physical findings, and most of them also had features more typical of fibromyalgia or chronic fatigue syndrome rather than Sjögren's.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Latent class analysis of symptoms associated with chronic fatigue syndrome and fibromyalgia.

Sullivan, P F, Smith, W, Buchwald, D·Psychological medicine·2002

Researchers studied 646 patients with ME/CFS and/or fibromyalgia to see if these are truly separate conditions or if they overlap significantly. Using statistical analysis of 32 common symptoms, they found that patients fell into four groups that differed in severity rather than type—suggesting these conditions are more similar to each other than previously thought. This challenges the traditional belief that ME/CFS and fibromyalgia are distinct disorders.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Psychiatric diagnoses in Gulf War veterans with fatiguing illness.

Lange, G, Tiersky, L, DeLuca, J et al.·Psychiatry research·1999

Researchers studied Gulf War veterans with severe fatigue to see whether psychiatric disorders could explain their illness. About half of the veterans with Gulf War Illness had similar rates of psychiatric diagnoses as healthy veterans, while the other half had more psychiatric problems. The study found that psychiatric conditions alone cannot account for the fatiguing illness these veterans experience.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Comparison of patients with chronic fatigue syndrome, fibromyalgia, and multiple chemical sensitivities.

Buchwald, D, Garrity, D·Archives of internal medicine·1994

This study compared 90 patients with three conditions that cause fatigue and other symptoms: ME/CFS, fibromyalgia, and multiple chemical sensitivities. The researchers found that these three conditions are very similar in many ways—patients often report overlapping symptoms, and many people meet the criteria for more than one condition. All three groups used a lot of healthcare services, visiting doctors about 22-40 times per year on average.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

The overdiagnosis of Lyme disease.

Steere, A C, Taylor, E, McHugh, G L et al.·JAMA·1993

This study looked at 788 people referred to a Lyme disease clinic who were thought to have Lyme disease. Researchers found that only 23% actually had active Lyme disease, while 57% did not have Lyme disease at all—many of these patients had chronic fatigue syndrome or fibromyalgia instead. The main problem was that patients were being incorrectly diagnosed with Lyme disease and given antibiotics that didn't help because they didn't actually have the infection.

Diagnostics
E2 ModeratePEM unclearPreliminaryCross-SectionalEditor reviewed

Primary fibromyalgia and the chronic fatigue syndrome.

Wysenbeek, A J, Shapira, Y, Leibovici, L·Rheumatology international·1991

This study looked at 33 people with fibromyalgia to see how many also had ME/CFS. While most reported significant fatigue, only about one in five people met the full criteria for ME/CFS. The researchers found that symptoms like swollen lymph nodes and fever were rare in fibromyalgia patients but might be more common in ME/CFS, suggesting these could help doctors tell the two conditions apart.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceObservationalEditor reviewed

Chronic fatigue syndrome 5 years after giardiasis: differential diagnoses, characteristics and natural course.

Mørch, Kristine, Hanevik, Kurt, Rivenes, Ann C et al.·BMC gastroenterology·2013

After a water contamination outbreak in Norway, researchers followed people who developed severe tiredness following a Giardia intestinal infection. Five years after infection, they found that about 41% of patients still had chronic fatigue syndrome, while about 21% had recovered completely. The study also identified other conditions like sleep problems and depression that sometimes occur alongside post-infectious fatigue.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceLongitudinalEditor reviewed

Post-infective and chronic fatigue syndromes precipitated by viral and non-viral pathogens: prospective cohort study.

Hickie, Ian, Davenport, Tracey, Wakefield, Denis et al.·BMJ (Clinical research ed.)·2006

This study followed 253 people in Australia who had three different infections (glandular fever, Q fever, and a virus causing joint pain) to see how many developed long-lasting fatigue and related symptoms. About 11% of people met the diagnostic criteria for chronic fatigue syndrome six months after infection, experiencing disabling fatigue, pain, thinking difficulties, and mood changes. The researchers found that the severity of the initial infection—not personality type, prior health, or the specific germ involved—was the main predictor of who would develop prolonged illness.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

[Epidemiologic study of chronic fatigue in primary care (general practice)].

Mann, A H, Mc Donald, E, Cope, H et al.·L'Encephale·1994

Researchers studied fatigue in patients visiting regular doctors' offices to understand how common it is and what causes it. They found that some patients had long-lasting, disabling fatigue, but these patients were very different from each other in why they thought they were tired. Most of these patients also had depression or other mental health conditions alongside their fatigue.

Diagnostics
E2 ModeratePEM unclearPreliminaryCross-SectionalEditor reviewed

Frequency and characteristics of chronic fatigue syndrome in multiple sclerosis patients at a university hospital in Eastern Saudi Arabia.

AlAmri, Abdullah S, AlShamrani, Foziah J, AlMohish, Noor M et al.·Journal of family & community medicine·2024

This study looked at fatigue in 225 people with multiple sclerosis (MS) to see how many also had chronic fatigue syndrome (CFS). About half of the MS patients experienced long-lasting fatigue lasting over 6 months. Researchers found that 7% of patients truly met the medical criteria for CFS, while 17% believed they had CFS but didn't meet the official diagnostic standards, suggesting confusion about what CFS actually is.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Serum GDF-15 Levels Accurately Differentiate Patients with Primary Mitochondrial Myopathy, Manifesting with Exercise Intolerance and Fatigue, from Patients with Chronic Fatigue Syndrome.

Bermejo-Guerrero, Laura, de Fuenmayor-Fernández de la Hoz, Carlos Pablo, Guerrero-Molina, María Paz et al.·Journal of clinical medicine·2023

This study tested whether a blood marker called GDF-15 could help doctors tell the difference between ME/CFS and a rare condition called primary mitochondrial myopathy (PMM), which affects how cells produce energy. Both conditions cause fatigue and exercise intolerance that can look very similar, but PMM requires different treatment. The researchers found that GDF-15 levels were very good at distinguishing between these two conditions, which could help patients get the right diagnosis faster without needing extensive genetic testing or muscle biopsies.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceObservationalEditor reviewed

Mistaken Identity: Many Diagnoses are Frequently Misattributed to Lyme Disease.

Kobayashi, Takaaki, Higgins, Yvonne, Melia, Michael T et al.·The American journal of medicine·2022

This study looked at over 1,000 patients who were referred to a hospital thinking they had Lyme disease, but actually didn't. The doctors found that 84% of these patients did not have Lyme disease at all. Instead, they had many other conditions causing their symptoms, including anxiety, depression, fibromyalgia, and chronic fatigue syndrome. This suggests that Lyme disease is being diagnosed too often when patients actually have other medical problems.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Seroepidemiological study of human brucellosis in the Northeast region of Meghalaya, India.

Shukla, Jayshree L, Husain, Aliabbas A, Lyngdoh, Samantha A et al.·Journal of family medicine and primary care·2022

This study looked at how many people in Northeast India have been exposed to brucellosis, a bacterial infection spread from animals to humans. Researchers tested 1,046 people with fever-like symptoms and found that 11% had antibodies showing past or current brucellosis infection. They noticed that women were more affected than men, and that eating meat was a risk factor. Importantly, three symptoms—fever of unknown cause, muscle pain, and chronic fatigue—were commonly seen in people with brucellosis.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Differentiating Multiple Sclerosis from Myalgic Encephalomyelitis and Chronic Fatigue Syndrome.

Jason, L A, Ohanian, D, Brown, A et al.·Insights in biomedicine·2017

This study compared how people with MS, ME, and chronic fatigue syndrome experience their illnesses. Researchers surveyed 120 people with MS and 269 people with ME/CFS about their symptoms using a standardized questionnaire. They found that people with ME/CFS reported more severe symptoms and greater functional limitations than people with MS, suggesting these conditions have different disability profiles.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Reference values for the Body Image Concern Inventory (BICI), the Whitely Index (WI), and the Checklist Individual Strength (CIS-20R): The Leiden Routine Outcome Monitoring Study.

Schulte-van Maaren, Yvonne W M, Giltay, Erik J, van Hemert, Albert M et al.·Journal of affective disorders·2014

This study established standard reference values for three questionnaires that measure different types of health concerns: body image worries, health anxiety, and fatigue/weakness. Researchers compared how 648 healthy people and 823 patients with these conditions answered the questionnaires, so doctors now have clear cutoff scores to help decide if treatments are working and when to adjust or stop therapy.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Medical comorbidities in patients with psychogenic nonepileptic spells (PNES) referred for video-EEG monitoring.

Dixit, Ronak, Popescu, Alexandra, Bagić, Anto et al.·Epilepsy & behavior : E&B·2013

This study looked at 280 patients seen at a hospital epilepsy unit to understand what health conditions are more common in people with psychogenic nonepileptic spells (PNES)—seizure-like episodes that aren't caused by epilepsy—compared to those with actual epilepsy. They found that patients with PNES were more likely to be female, have a history of trauma, and experience conditions like fibromyalgia, chronic fatigue syndrome, chronic pain, and irritable bowel syndrome. The researchers suggest these patterns might help doctors identify PNES earlier and order the right tests sooner.

Diagnostics
E2 ModeratePEM unclearPreliminaryCross-SectionalEditor reviewed

Could mitochondrial dysfunction be a differentiating marker between chronic fatigue syndrome and fibromyalgia?

Castro-Marrero, Jesús, Cordero, Mario D, Sáez-Francas, Naia et al.·Antioxidants & redox signaling·2013

This study looked at whether problems in the energy-producing parts of cells (mitochondria) might be different between ME/CFS and fibromyalgia, two conditions that cause fatigue and are often confused with each other. Researchers tested blood cells from people with ME/CFS, fibromyalgia, and healthy people, measuring energy-related markers and signs of cellular damage. They found that both conditions showed some mitochondrial problems, but the patterns were different—suggesting mitochondrial dysfunction might help doctors tell these two conditions apart.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceObservationalEditor reviewed

Fatigue heralding multiple sclerosis.

Berger, Joseph R, Pocoski, Jennifer, Preblick, Ronald et al.·Multiple sclerosis (Houndmills, Basingstoke, England)·2013

This study looked at medical records to see how often fatigue appears before someone is diagnosed with multiple sclerosis (MS). Researchers found that about 29% of newly diagnosed MS patients had been labeled with fatigue in the 3 years before their MS diagnosis, often 1–2 years earlier. The findings suggest that persistent fatigue might be an early warning sign of MS, and doctors should carefully evaluate people with unexplained fatigue for possible neurological causes.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Implications of gender in chronic Lyme disease.

Wormser, Gary P, Shapiro, Eugene D·Journal of women's health (2002)·2009

This study compared three groups of patients: those with confirmed Lyme disease, those with lingering symptoms after Lyme disease treatment (post-Lyme disease syndrome), and those diagnosed with 'chronic Lyme disease' (a less clearly defined condition). The researchers found that women made up a much larger percentage of the chronic Lyme disease group compared to the other two groups. This suggests that some patients labeled with chronic Lyme disease may actually have other conditions like fibromyalgia or chronic fatigue syndrome that also affect more women.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Negotiating the diagnostic uncertainty of contested illnesses: physician practices and paradigms.

Swoboda, Debra A·Health (London, England : 1997)·2008

This study surveyed 800 U.S. doctors to understand how they diagnose ME/CFS and similar illnesses that lack clear lab tests or agreed-upon causes. Researchers found that many doctors do diagnose these conditions, even without complete scientific consensus, by using practical strategies like consulting expert resources, ordering specific tests, and considering how the body might be affected. The study shows that doctors can rationally diagnose ME/CFS by using thoughtful decision-making processes, and that patients may benefit from seeing doctors who use these careful diagnostic approaches.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Awareness and knowledge of fibromyalgia among French rheumatologists and general practitioners.

Blotman, F, Thomas, E, Myon, E et al.·Clinical and experimental rheumatology·2005

This study asked French doctors (both general practitioners and specialists called rheumatologists) how much they knew about fibromyalgia, a condition with widespread muscle pain and fatigue. The results showed that most doctors had never formally learned about this condition in medical school, and many did not fully recognize it as a legitimate disease. The study highlights that doctors need better training to understand and properly diagnose fibromyalgia.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Chronic fatigue syndrome of childhood. Comparative study with emotional disorders.

Garralda, M Elena, Rangel, Luiza·European child & adolescent psychiatry·2005

This study compared children diagnosed with ME/CFS to children with emotional disorders like anxiety and depression to see how these conditions differ. While both groups of children experienced some similar emotional challenges, children with ME/CFS reported more severe tiredness and physical symptoms, and were more likely to have had infections or medical problems before getting sick. The results show that ME/CFS and emotional disorders can look similar in some ways but have important differences.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

General practitioners' perceptions of chronic fatigue syndrome and beliefs about its management, compared with irritable bowel syndrome: qualitative study.

Raine, Rosalind, Carter, Simon, Sensky, Tom et al.·BMJ (Clinical research ed.)·2004

This study asked 46 general practitioners (GPs) in England about their views on ME/CFS and compared these with their views on irritable bowel syndrome. The researchers found that many GPs held negative stereotypes about ME/CFS patients, viewing them unfavorably because the condition has no clear physical marker, changes how it's classified over time, and conflicts with traditional ideas about work and illness. These negative attitudes made it harder for GPs to provide effective care.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Unexplained fatigue syndromes in a multinational primary care sample: specificity of definition and prevalence and distinctiveness from depression and generalized anxiety.

Skapinakis, Petros, Lewis, Glyn, Mavreas, Venetsanos·The American journal of psychiatry·2003

This study looked at how different definitions of unexplained fatigue affect how many people are diagnosed and whether they also have depression or anxiety. Researchers interviewed over 5,400 primary care patients from 14 countries and found that when they required more physical symptoms in addition to fatigue, fewer people were diagnosed, but those diagnosed were more likely to also have depression or anxiety.

Diagnostics
E2 ModeratePEM not requiredWeak / uncertainObservationalEditor reviewed

Non-vascular claudication: a clinical conundrum.

Fasih, T, Pickin, M, Cuschieri, R J·International journal of clinical practice·2003

Doctors sometimes see patients complaining of leg pain that resembles poor circulation (claudication), but the pain isn't actually caused by blood vessel problems. This study looked at over 1,000 patients with suspected circulation problems and found that 33 had other causes for their symptoms, including spine problems, nerve damage, or other conditions. One patient was diagnosed with chronic fatigue syndrome (ME/CFS). The study highlights that doctors need to correctly identify the real cause of symptoms before recommending treatments.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Self-reported symptoms and medical conditions among 11,868 Gulf War-era veterans: the Seabee Health Study.

Gray, Gregory C, Reed, Robert J, Kaiser, Kevin S et al.·American journal of epidemiology·2002

This study surveyed nearly 12,000 Navy Seabees who served around the time of the 1991 Gulf War to understand their health problems. Compared to Seabees who didn't deploy to the Gulf, those who did reported significantly more health issues, including chronic fatigue syndrome, PTSD, chemical sensitivity, and irritable bowel syndrome. Women, reserve members, and certain military units had higher rates of these combined symptoms.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

[Patients with fatigue in family practice: prevalence and treatment].

Kenter, E G, Okkes, I M·Nederlands tijdschrift voor geneeskunde·1999

This study looked at how often people visit their doctor complaining of fatigue and what doctors do about it. Researchers tracked visits from general practitioners across the Netherlands over 10 years, involving over 93,000 patient visits. They found that about 92 out of every 1,000 patients saw their doctor each year because of fatigue, but only about 4% had fatigue lasting 6 months or longer.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalEditor reviewed

Absence of Borrelia burgdorferi-specific immune complexes in chronic fatigue syndrome.

Schutzer, S E, Natelson, B H·Neurology·1999

This study tested whether people with ME/CFS have signs of Lyme disease infection in their blood. Researchers compared 39 ME/CFS patients to 40 healthy people using a specialized test that looks for Borrelia burgdorferi, the bacterium that causes Lyme disease. None of the patients or controls showed signs of this infection, suggesting that Lyme disease is not the hidden cause of ME/CFS in people without typical Lyme disease symptoms like the characteristic rash or joint problems.

Diagnostics
E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Chronic fatigue complaints in primary care: incidence and diagnostic patterns.

Ward, M H, DeLisle, H, Shores, J H et al.·The Journal of the American Osteopathic Association·1996

This study looked at how doctors in a primary care clinic evaluate patients who complain of chronic fatigue. Researchers reviewed 425 patient charts and found that when patients mentioned chronic fatigue, doctors often did not perform complete evaluations—skipping important tests, mental health screening, and sleep history questions. Most doctors diagnosed patients with depression or general fatigue rather than investigating the chronic fatigue complaint thoroughly.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceMethods-PaperEditor reviewed

How a Clinician Makes a Diagnosis for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).

Vallings, Rosamund·Methods in molecular biology (Clifton, N.J.)·2025

This guide explains how experienced doctors diagnose ME/CFS when standard blood tests or scans cannot detect the illness. Since there is no single definitive test for ME/CFS, doctors must carefully evaluate a patient's symptoms, medical history, and how the illness affects their daily functioning. This chapter walks through the practical steps clinicians use to identify ME/CFS and distinguish it from other conditions.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryEditor reviewed

Pediatric Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): A Diagnostic and Communication Case Study for Health Care Providers in Training.

Brimmer, Dana J, Lin, Jin-Mann S, Selinger, Howard A et al.·MedEdPORTAL : the journal of teaching and learning resources·2025

This study tested whether a short educational program could help future doctors, nurses, and physician assistants better understand pediatric ME/CFS. After a 40-minute lesson with videos and materials, students showed major improvements in recognizing ME/CFS as a real medical condition and felt more confident talking to patients about it. The results suggest that better training about ME/CFS in medical schools could help young patients get diagnosed and treated more effectively.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryMethods-PaperEditor reviewed

Health Controversies: Long-Term Disagreement Management Challenges.

Jackson, Sally·Journal of health communication·2024

This paper examines how major disagreements about health topics—including ME/CFS—develop and persist over long periods of time across different countries and communities. The author explains that these health controversies involve many people with different viewpoints who argue in multiple places (medical journals, courts, social media, etc.), and that how we manage these disagreements matters. The study shows that ME/CFS is a particularly important example because disagreements about it have shaped how institutions are designed to handle health disputes.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryMethods-PaperEditor reviewed

A synthetic data generation system for myalgic encephalomyelitis/chronic fatigue syndrome questionnaires.

Lacasa, Marcos, Prados, Ferran, Alegre, José et al.·Scientific reports·2023

This study created an artificial intelligence tool that can predict what ME/CFS patients might answer on symptom questionnaires. Researchers trained the tool using responses from 2,522 ME/CFS patients from a hospital in Spain, and it learned to predict answers accurately. The tool could help researchers study the disease more easily by generating realistic patient data for testing new ideas.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryMethods-PaperEditor reviewed

Impact of Misdiagnosis in Case-Control Studies of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Malato, João, Graça, Luís, Sepúlveda, Nuno·Diagnostics (Basel, Switzerland)·2023

This study examined how misdiagnosis affects ME/CFS research results. The researchers found that when patients are incorrectly diagnosed with ME/CFS (or vice versa), it becomes much harder for studies to find real connections between potential causes and the disease. To get reliable results, studies need to include at least 500-1000 people per group, which is larger than many current ME/CFS studies.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceEditorialEditor reviewed

[Chronic fatigue: What investigations? And what for?].

Gramont, B, Goutte, J, Féasson, L et al.·La Revue de medecine interne·2023

When people feel tired all the time, doctors need to figure out why. This article explains how doctors should approach chronic fatigue: by asking careful questions, doing a physical exam, and using only necessary blood tests. It emphasizes that chronic fatigue often has multiple causes—physical, emotional, and life circumstances—working together, and that exercise testing and personalized activity programs are the most helpful treatments.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceEditor reviewed

Evaluation of a Webinar to Increase Health Professionals' Knowledge about Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).

Froehlich, Laura, Niedrich, Jasmin, Hattesohl, Daniel B R et al.·Healthcare (Basel, Switzerland)·2023

Many doctors and health professionals don't know enough about ME/CFS, which makes it harder for patients to get proper care. Researchers created an online webinar to teach German-speaking healthcare workers about ME/CFS and tested whether it helped them learn. The study found that the webinar successfully increased doctors' knowledge about the illness, suggesting that online education could be a practical way to train more healthcare providers.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

[Chronic fatigue syndrom: modern aspects of diagnosis and treatment].

Vorobyova, Yu D, Danilov, A B·Zhurnal nevrologii i psikhiatrii imeni S.S. Korsakova·2021

This article reviews how ME/CFS develops by looking at both genes and environmental factors that trigger the illness. The authors explain known genetic problems found in ME/CFS patients, what can start the disease, and how these factors combine to cause the symptoms people experience. They also describe a systematic approach to diagnosing and treating ME/CFS.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryEditor reviewed

Epistemic in/justice in patient participation. A discourse analysis of the Dutch ME/CFS Health Council advisory process.

de Boer, Marjolein Lotte·Sociology of health & illness·2021

This study looked at how ME/CFS patients were involved in advising the Dutch Health Council between 2013-2018. The researchers found that patient representatives mainly shared medical/scientific knowledge about ME/CFS as a physical illness, avoiding discussion of psychological factors. While this approach helped patients be taken more seriously, it may have actually limited what kinds of knowledge and experiences patients could contribute, and it might reinforce incomplete understandings of the disease.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceGuidelineEditor reviewed

European Network on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (EUROMENE): Expert Consensus on the Diagnosis, Service Provision, and Care of People with ME/CFS in Europe.

Nacul, Luis, Authier, François Jérôme, Scheibenbogen, Carmen et al.·Medicina (Kaunas, Lithuania)·2021

This study brings together ME/CFS experts from 22 European countries to agree on how to diagnose the illness and provide better care for patients. The researchers and healthcare professionals worked together with people who have ME/CFS to create recommendations that can help doctors recognize and treat the condition more consistently across Europe. Their goal was to improve diagnosis and healthcare services for ME/CFS patients everywhere.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryCase-ControlEditor reviewed

Young and exhausted.

Oleksak, Filip, Durdik, Peter, Jakusova, Lubica et al.·Advances in respiratory medicine·2021

This case report describes a young patient who was diagnosed with ME/CFS (extreme exhaustion lasting at least six months) but actually had a different, treatable heart and lung condition. The doctors used a special exercise test called cardiopulmonary exercise testing to discover the real cause. This story reminds us that it's important to carefully check for other medical conditions before diagnosing someone with ME/CFS, especially in children and young people.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryCase-ControlEditor reviewed

Idiopathic combined adrenocorticotropin and growth hormone deficiency mimicking chronic fatigue syndrome.

Tokumasu, Kazuki, Ochi, Kanako, Otsuka, Fumio·BMJ case reports·2021

This case describes a 42-year-old man who was told he had chronic fatigue syndrome (CFS) and fibromyalgia, but was actually missing two important hormones: cortisol and growth hormone. When doctors tested his pituitary gland (which makes these hormones), they found deficiencies that weren't caught before. After starting treatment with these hormones, his severe tiredness, muscle pain, and depression all improved significantly.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainEditor reviewed

ME/CFS: Past, Present and Future.

Weir, William, Speight, Nigel·Healthcare (Basel, Switzerland)·2021

This article reviews the history and current understanding of ME/CFS, arguing that the condition has a biological basis rather than being primarily psychological. The authors emphasize that scientific research, not psychological theories, is the path forward for properly understanding and treating ME/CFS. They highlight how patients have suffered from misunderstandings about their condition's cause.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryCase-ControlEditor reviewed

Chronic Fatigue Syndrome: A Case Report Highlighting Diagnosing and Treatment Challenges and the Possibility of Jarisch-Herxheimer Reactions If High Infectious Loads Are Present.

Straub, Rachel K, Powers, Christopher M·Healthcare (Basel, Switzerland)·2021

This study follows one patient's journey with severe ME/CFS, examining how past infections and health conditions may have contributed to her illness and how various treatments affected her recovery. The case highlights that some treatments can paradoxically make symptoms worse before improvement occurs, especially if someone has high levels of lingering infections. The patient eventually improved enough to return to graduate school, though her experience also shows how serious and disabling ME/CFS can be for some people.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryEditorialEditor reviewed

The Role of Prevention in Reducing the Economic Impact of ME/CFS in Europe: A Report from the Socioeconomics Working Group of the European Network on ME/CFS (EUROMENE).

Pheby, Derek F H, Araja, Diana, Berkis, Uldis et al.·Medicina (Kaunas, Lithuania)·2021

This European research report examined whether ME/CFS could be prevented and what money might be saved if prevention programs worked. The researchers found that preventing ME/CFS before it starts is very difficult because the illness seems to result from a mix of genetic factors and environmental exposures that we don't fully understand yet. However, they identified that safer use of certain agricultural chemicals like organophosphates could help, and catching ME/CFS earlier through better doctor training could reduce how severe the illness becomes and lower healthcare costs.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceEditorialEditor reviewed

Treating medically unexplained symptoms via improving access to psychological therapy (IAPT): major limitations identified.

Geraghty, Keith, Scott, Michael J·BMC psychology·2020

This paper examines a UK mental health program called IAPT that offers psychological therapy for conditions with unexplained physical symptoms, including ME/CFS. The authors identified serious problems with how the program treats ME/CFS patients, including using treatments that haven't been proven to work, overstating how many people recover, and not being honest about how many patients drop out. The paper calls for better independent checking of the program and warns that psychology should not be the automatic treatment when doctors don't understand what's causing physical symptoms.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeEditor reviewed

Neurasthenia: tracing the journey of a protean malady.

Bhola, Poornima, Chaturvedi, Santosh K·International review of psychiatry (Abingdon, England)·2020

This article traces the history of 'neurasthenia,' an old medical diagnosis meaning nervous exhaustion that was popular in the past but has largely disappeared from modern medicine. The authors explain how this diagnosis reflected the culture, biases, and social beliefs of its time, and how similar conditions today—like ME/CFS and fibromyalgia—are trying to describe the same patient experience of fatigue, pain, and weakness without clear medical causes.

Diagnostics
E3 PreliminaryPEM requiredModerate confidenceMethods-PaperEditor reviewed

The Development of a Consistent Europe-Wide Approach to Investigating the Economic Impact of Myalgic Encephalomyelitis (ME/CFS): A Report from the European Network on ME/CFS (EUROMENE).

Pheby, Derek F H, Araja, Diana, Berkis, Uldis et al.·Healthcare (Basel, Switzerland)·2020

This study created a unified European system for measuring how much ME/CFS costs society in terms of healthcare, lost work, and other expenses. The researchers found that ME/CFS places a heavy financial burden on Europe, mostly because patients lose work productivity. However, they discovered that calculating these true costs is very difficult because different countries use different diagnostic criteria and many doctors don't diagnose ME/CFS, leaving many patients uncounted.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryEditorialEditor reviewed

Differentiating Psychosomatic, Somatopsychic, Multisystem Illnesses, and Medical Uncertainty.

Bransfield, Robert C, Friedman, Kenneth J·Healthcare (Basel, Switzerland)·2019

Doctors often struggle to distinguish between illnesses caused by psychological factors, illnesses where physical symptoms cause psychological effects, true multisystem diseases (affecting many body systems), and situations where medical causes haven't been found yet. This article discusses how using outdated or inaccurate diagnostic labels—like 'all in your head'—can harm patients and delay proper diagnosis. The authors argue that many conditions previously thought to be purely psychological may actually involve the immune system and microbiome, and that doctors need better training to avoid misdiagnosing complex diseases like ME/CFS.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Comprehensive Review.

Cortes Rivera, Mateo, Mastronardi, Claudio, Silva-Aldana, Claudia T et al.·Diagnostics (Basel, Switzerland)·2019

ME/CFS is a serious, long-lasting illness that affects the brain and causes extreme fatigue and other symptoms, but doctors don't yet know what causes it. The condition is three times more common in women than men, usually starts between ages 20 and 45, and currently has no specific cure. This review summarizes what scientists know about ME/CFS by looking at how it affects the nervous system, immune system, and hormones.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceMethods-PaperEditor reviewed

The development of a short form of the DePaul Symptom Questionnaire.

Sunnquist, Madison, Lazarus, Savitri, Jason, Leonard A·Rehabilitation psychology·2019

Researchers created a shorter version of a commonly used questionnaire that measures ME/CFS symptoms. Instead of 99 questions, the new version has only 14 questions that capture the most important symptoms. This shorter form works well at identifying people with ME/CFS and can be easier for patients to complete, especially those with fatigue and thinking difficulties.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryCase-ControlEditor reviewed

Varied Presentation of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and the Needs for Classification and Clinician Education: A Case Series.

Martín-Martínez, Eva, Martín-Martínez, Mercedes·Clinical therapeutics·2019

This study looked at three individual ME/CFS patient cases to understand why this disease presents so differently from person to person. The researchers found that patients often wait years for a correct diagnosis because many doctors don't understand ME/CFS well, leading to misdiagnosis and delays in treatment. The study suggests that organizing patient information carefully could help doctors and researchers identify different subtypes of ME/CFS.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryMethods-PaperEditor reviewed

Approaching recovery from myalgic encephalomyelitis and chronic fatigue syndrome: Challenges to consider in research and practice.

Devendorf, Andrew R, Jackson, Carly T, Sunnquist, Madison et al.·Journal of health psychology·2019

This study interviewed 13 doctors who treat ME/CFS to understand the challenges they face when trying to measure whether patients are getting better. The researchers found four main areas that make recovery difficult to assess: differences in how the illness affects people at different ages, the fact that ME/CFS shows up differently in different patients, trouble keeping track of patients over time, and practical difficulties in measuring improvement.

InterventionsDiagnostics
E3 PreliminaryPEM unclearModerate confidenceMethods-PaperEditor reviewed

The Development of the DePaul Symptom Questionnaire: Original, Expanded, Brief, and Pediatric Versions.

Jason, Leonard A, Sunnquist, Madison·Frontiers in pediatrics·2018

Researchers created a questionnaire called the DePaul Symptom Questionnaire (DSQ) to help doctors and scientists consistently measure ME/CFS symptoms in patients. The questionnaire was refined over time and adapted for different groups, including children. This tool helps ensure that when people are diagnosed with ME/CFS, they're being assessed in the same way across different clinics and studies.

Diagnostics
E3 PreliminaryPEM requiredModerate confidenceGuidelineEditor reviewed

[Diagnosis and Treatment of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome].

Kuratsune, Hirohiko·Brain and nerve = Shinkei kenkyu no shinpo·2018

This document presents official diagnostic criteria for ME/CFS developed by Japanese health authorities in 2016. These criteria were designed to help doctors in primary care clinics recognize and diagnose ME/CFS more consistently. The document also summarizes current treatment approaches and expected outcomes based on practices at major medical centers in Japan.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

The biopolitics of CFS/ME.

Karfakis, Nikos·Studies in history and philosophy of biological and biomedical sciences·2018

This paper examines how ME/CFS is shaped by different groups—doctors, scientists, government officials, and patients themselves—who all try to define and understand the illness. The author shows that ME/CFS sits uncomfortably between medical and psychiatric explanations, which makes it hard for everyone to agree on what it is and how to treat it. Patients aren't just passive recipients of medical care; they actively educate themselves and push back against explanations they disagree with, which influences how the illness is understood.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceGuidelineEditor reviewed

Dutch Health Council Advisory Report on Myalgic Encephalomyelitis and Chronic Fatigue Syndrome: Taking the Wrong Turn.

Twisk, Frank·Diagnostics (Basel, Switzerland)·2018

The Dutch Health Council released an official report recognizing ME/CFS as a serious, multi-system disease rather than primarily a psychological condition. The report recommends establishing specialized medical centers, training doctors better about ME/CFS, and improving how disability benefits are assessed for patients. However, the report's new definition of ME/CFS may create unintended problems for future research and patient care.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryEditor reviewed

Exploring the potential role of the advanced nurse practitioner within a care path for patients with chronic fatigue syndrome.

Ryckeghem, Hannah, Delesie, Liesbeth, Tobback, Els et al.·Journal of advanced nursing·2017

This study asked ME/CFS patients and their doctors in Belgium what they thought about their care. Both groups reported feeling isolated and unsupported—patients didn't know who to turn to for reliable information, and doctors weren't sure how to help. The researchers suggest that having a specialized nurse coordinator could improve communication, provide education, and help different healthcare providers work together better for ME/CFS patients.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceCross-SectionalEditor reviewed

"It´s incredible how much I´ve had to fight." Negotiating medical uncertainty in clinical encounters.

Lian, Olaug S, Robson, Catherine·International journal of qualitative studies on health and well-being·2017

This study asked 256 people with long-term unexplained fatigue in Norway to describe their experiences with doctors. Most patients felt their doctors didn't believe them, gave unhelpful psychological explanations, didn't do proper physical exams, and didn't listen to what they knew about their own condition. Patients described these encounters using words like 'fighting' and 'war,' showing how stressful and adversarial these medical visits felt.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceReview-NarrativeEditor reviewed

Epistemic injustice in healthcare encounters: evidence from chronic fatigue syndrome.

Blease, Charlotte, Carel, Havi, Geraghty, Keith·Journal of medical ethics·2017

Many doctors are uncertain whether ME/CFS is a real medical condition, and some patients report feeling disbelieved or suspected by healthcare providers. This study shows that patients with ME/CFS often experience unfair treatment in medical settings because doctors may not take their symptoms seriously. This type of dismissal—called epistemic injustice—can delay diagnosis and proper care for people with this serious illness.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceReview-NarrativeEditor reviewed

Severity Scales for Use in Primary Health Care to Assess Chronic Fatigue Syndrome/Myalgic Encephalomyelitis.

Hardcastle, Sharni Lee, Brenu, Ekua Weba, Johnston, Samantha et al.·Health care for women international·2016

ME/CFS affects people very differently—some have mild symptoms while others are severely disabled. This study reviewed different tools doctors can use to measure how severe a patient's ME/CFS is based on their symptoms and ability to function physically and mentally. Using these measurement tools helps doctors and researchers identify different groups of ME/CFS patients, which could lead to better diagnosis and treatment.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceReview-NarrativeEditor reviewed

Chronic fatigue syndrome and sleep disorders: clinical associations and diagnostic difficulties.

Ferré, A·Neurologia·2016

This review looked at the connection between ME/CFS and sleep problems. Many people with ME/CFS experience non-restorative sleep (where sleep doesn't feel refreshing) and fatigue, but these same symptoms can happen with other sleep disorders. The key finding is that doctors need to carefully check whether patients have a separate sleep disorder before or alongside an ME/CFS diagnosis, because treating the sleep problem might help improve overall quality of life.

SleepDiagnostics
E3 PreliminaryPEM unclearModerate confidenceCross-SectionalEditor reviewed

Implementing resources to support the diagnosis and management of Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) in primary care: A qualitative study.

Bayliss, Kerin, Riste, Lisa, Band, Rebecca et al.·BMC family practice·2016

This study looked at whether special training and information resources for GPs could help them better diagnose and manage ME/CFS. Researchers interviewed patients and doctors in North West England and found that while the resources were helpful when used properly, most GPs didn't actually use them—either because they were too busy, didn't see enough ME/CFS patients to remember the training, or thought the condition should only be managed by specialists.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

[Chronic fatifue syndrome.].

Holecek, V, Rokyta, R·Ceskoslovenska fysiologie·2016

This review article provides an overview of ME/CFS, explaining what it is, how common it is, and how doctors diagnose and treat it. The condition lasts about 6 months or longer in adults and at least 3 months in children, causing persistent fatigue and other symptoms. The article covers multiple possible causes including biological, genetic, infectious, and psychological factors, as well as the economic impact of the disease.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceEditorialEditor reviewed

Investigating unexplained fatigue in general practice with a particular focus on CFS/ME.

Bansal, Amolak S·BMC family practice·2016

This paper looks at how doctors in general practice can identify ME/CFS in patients who come in complaining of unexplained tiredness. The authors explain that ME/CFS is a real condition with specific diagnostic criteria, and that normal blood tests (ruling out infections, thyroid problems, and other common causes) combined with careful clinical assessment can confidently diagnose it. They argue that early diagnosis in primary care can reduce patient worry and prevent unnecessary, costly tests.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryCross-SectionalEditor reviewed

Assessing current functioning as a measure of significant reduction in activity level.

Thorpe, Taylor, McManimen, Stephanie, Gleason, Kristen et al.·Fatigue : biomedicine, health & behavior·2016

ME/CFS diagnosis requires patients to show a significant drop in their activity levels, but doctors haven't agreed on how to measure this drop consistently. This study tested whether a common health survey (the SF-36) could accurately measure when someone's activities have substantially decreased. The researchers found that certain parts of this survey do a good job of identifying major reductions in functioning and can distinguish ME/CFS patients from healthy people.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceMethods-PaperEditor reviewed

Test-Retest Reliability of the DePaul Symptom Questionnaire.

Jason, Leonard A, So, Suzanna, Brown, Abigail A et al.·Fatigue : biomedicine, health & behavior·2015

Researchers tested whether the DePaul Symptom Questionnaire (DSQ)—a tool designed to help doctors diagnose ME/CFS—gives consistent results when used multiple times. They asked 26 people with ME/CFS and 25 healthy people to answer the same questions at different times. The questionnaire proved reliable, meaning patients' answers were consistent, making it a trustworthy tool for identifying who has ME/CFS.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceCross-SectionalEditor reviewed

Complications in operationalizing lifelong fatigue as an exclusionary criterion.

Sunnquist, Madison, Jason, Leonard A, Brown, Abigail et al.·Journal of prevention & intervention in the community·2015

This study looked at whether people who have felt tired their whole lives should be excluded from ME/CFS diagnoses. Researchers asked patients detailed questions about lifelong fatigue and found it was very difficult to determine who truly had it. Importantly, people with and without lifelong fatigue had similar ME/CFS symptoms, suggesting this exclusion rule may not be helpful.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceReview-NarrativeEditor reviewed

Chronic Fatigue Syndrome: Case Definitions and Diagnostic Assessment.

Williams, Yolonda J, Jantke, Rachel L, Jason, Leonard A·New York State psychologist·2014

This article explains why doctors have difficulty diagnosing ME/CFS and why patients often struggle to get proper care. The researchers found that there are disagreements about how to define and diagnose the illness, which makes it harder for healthcare providers to recognize it and treat it correctly. They call for better education of doctors and clearer diagnostic guidelines.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

What is called symptom?

Eriksen, Thor Eirik, Risør, Mette Bech·Medicine, health care, and philosophy·2014

This paper explores what we actually mean by the word 'symptom' in medicine. The authors argue that when doctors can't find a clear medical cause for illness—like ME/CFS—our usual way of thinking about symptoms breaks down. They suggest we need to understand symptoms in broader ways, including how patients' social lives, personal experiences, and individual circumstances shape how they experience illness.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceCross-SectionalEditor reviewed

Adolescents and mothers value referral to a specialist service for chronic fatigue syndrome or myalgic encephalopathy (CFS/ME).

Beasant, Lucy, Mills, Nicola, Crawley, Esther·Primary health care research & development·2014

This study asked 13 mothers and 12 teenagers with ME/CFS about their experiences getting help from a specialist ME/CFS service. Most families found it difficult and took a long time to access the specialist clinic, but once they got there, both teenagers and mothers felt it was valuable. The specialist service helped confirm the diagnosis, improved symptom management, and helped communication between doctors and schools.

InterventionsDiagnostics
E3 PreliminaryPEM unclearPreliminaryMethods-PaperEditor reviewed

Method Issues in Epidemiological Studies of Medically Unexplained Symptom-based Conditions in Veterans.

Coughlin, Steven S, McNeil, Rebecca B, Provenzale, Dawn T et al.·Journal of military and veterans' health·2013

This study examined how researchers diagnose ME/CFS and related conditions in veterans, particularly those who served in the 1990-1991 Gulf War. The researchers found that many veterans had other medical conditions that could complicate or mask ME/CFS diagnosis. The study highlights that how doctors define and diagnose these conditions matters a lot, and different approaches can lead to very different results.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryRegistry-ResourceEditor reviewed

A pilot registry of unexplained fatiguing illnesses and chronic fatigue syndrome.

Brimmer, Dana J, Maloney, Elizabeth, Devlin, Rebecca et al.·BMC research notes·2013

This study tested whether doctors and patient groups could help identify people with ME/CFS for a patient registry (a database of medical information). Researchers in Georgia contacted healthcare providers and a local ME/CFS support group to refer patients for evaluation. Of 104 people who completed clinic visits, 36% had ME/CFS, 17% had fatigue that didn't quite meet ME/CFS criteria, and 47% had other medical or psychiatric conditions instead. This shows that many people with fatigue symptoms may have treatable conditions other than ME/CFS.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryObservationalEditor reviewed

Diagnosing Chronic Fatigue Syndrome in South Asians: Lessons from a Secondary Analysis of a UK Qualitative Study.

De Silva, R Erandie Ediriweera, Bayliss, Kerin, Riste, Lisa et al.·Journal of family medicine and primary care·2013

This study looked at why ME/CFS is rarely diagnosed in South Asia, even though people there experience its symptoms. By interviewing South Asian patients, doctors, and community leaders in the UK, researchers found that cultural beliefs, language barriers, and doctors' lack of knowledge about ME/CFS make it harder for people to get a proper diagnosis. The study suggests that raising awareness about ME/CFS in South Asia could help more people get diagnosed and treated.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

Chronic fatigue syndrome in the UK armed forces.

Le Blackadder-Coward, J C Q, Perry, S·Journal of the Royal Naval Medical Service·2013

This study examined how ME/CFS (also called CFS) affects people serving in the UK military, and how the condition should be recognized and managed in this specific setting. ME/CFS can significantly impact a service member's career and ability to work in challenging military environments. The article discusses how doctors can better identify and treat this condition in military personnel.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceMethods-PaperEditor reviewed

Minimum data elements for research reports on CFS.

Jason, Leonard A, Unger, Elizabeth R, Dimitrakoff, Jordan D et al.·Brain, behavior, and immunity·2012

Researchers noticed that different ME/CFS studies were collecting and reporting information in very different ways, making it hard to compare results across laboratories. This paper outlines the essential information that all ME/CFS research studies should include—like how patients were selected, what their characteristics are, and how they were tested—so that future studies can be compared fairly and findings can be better understood.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeEditor reviewed

Chronic fatigue syndrome or myalgic encephalomyelitis.

Burns, Dianne·Nursing standard (Royal College of Nursing (Great Britain) : 1987)·2012

ME/CFS is a serious illness that affects many body systems, especially the nervous and immune systems, and can impact anyone regardless of age, race, or background. This guideline article helps nurses and healthcare workers recognize and support ME/CFS patients by providing practical knowledge and management strategies. The recommendations can be used by healthcare professionals in different settings to better care for people living with this condition.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceMethods-PaperEditor reviewed

Developing resources to support the diagnosis and management of Chronic Fatigue Syndrome/Myalgic Encephalitis (CFS/ME) in primary care: a qualitative study.

Hannon, Kerin, Peters, Sarah, Fisher, Louise et al.·BMC family practice·2012

This study asked patients, carers, and doctors in North West England what would help them better diagnose and manage ME/CFS in general practice. The researchers found that patients want to be believed and taken seriously, while doctors said they need better training and support. Based on everyone's feedback, the team created practical tools including a DVD for patients, information leaflets, and online training for doctors.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceCross-SectionalEditor reviewed

Fatigue Scales and Chronic Fatigue Syndrome: Issues of Sensitivity and Specificity.

Jason, Leonard A, Evans, Meredyth, Brown, Molly et al.·Disability studies quarterly·2011

This study tested different questionnaires and scales designed to measure fatigue in ME/CFS patients to see how well they could identify people with the disease. Researchers found that most common fatigue measurement tools didn't work very well—some were good at spotting sick people but missed others, or vice versa. The most promising tool was a specific question about fatigue that gets worse after physical activity, which is a key feature of ME/CFS.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryCross-SectionalEditor reviewed

Patients' hopes and expectations of a specialist chronic fatigue syndrome/ME service: a qualitative study.

McDermott, C, Lynch, J, Leydon, G M·Family practice·2011

This study asked 20 newly referred ME/CFS patients what they hoped to gain from visiting a specialist service. Patients most wanted a clear diagnosis, better understanding of their illness, practical guidance on managing it, and hope for the future. Most patients felt uncertain about ME/CFS and wanted more information earlier in their illness journey, rather than waiting to see a specialist.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

[The chronic asthenia syndrome: a clinical approach].

Young, Pablo, Finn, Bárbara C, Bruetman, Julio et al.·Medicina·2010

Fatigue is one of the most common reasons people visit doctors, affecting about 30% of patients. This article explains how doctors should think about different types of fatigue—including chronic fatigue syndrome (ME/CFS), which affects 0.2–0.7% of people. The authors emphasize that finding and treating the underlying cause is the best approach, though about 20% of patients never get a clear diagnosis.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceObservationalEditor reviewed

Making the diagnosis of Chronic Fatigue Syndrome/Myalgic Encephalitis in primary care: a qualitative study.

Chew-Graham, Carolyn, Dowrick, Christopher, Wearden, Alison et al.·BMC family practice·2010

This study asked 22 general practitioners (GPs) about their experiences diagnosing ME/CFS in their clinics. GPs said they find it hard to understand what ME/CFS is, and they typically focus on ruling out other diseases rather than confidently saying a patient has ME/CFS. Many GPs worried that giving someone an ME/CFS diagnosis might actually harm them, and they weren't sure what to do to help these patients once diagnosed.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryCross-SectionalEditor reviewed

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) in adults: a qualitative study of perspectives from professional practice.

Horton, Simon M C, Poland, Fiona, Kale, Swati et al.·BMC family practice·2010

This study spoke with six healthcare providers who were praised by ME/CFS patients for being helpful and understanding. The researchers asked these doctors and specialists what they thought worked best when treating ME/CFS. The key finding was that patients benefit most from doctors who truly listen, show respect, build trust, and recognize how serious and complex the condition is—rather than those who dismiss or minimize ME/CFS.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryCross-SectionalEditor reviewed

A discourse analytic study of ME/CFS (Chronic Fatigue Syndrome) sufferers' experiences of interactions with doctors.

Guise, Jennie, McVittie, Chris, McKinlay, Andy·Journal of health psychology·2010

This study looked at how ME/CFS patients describe their experiences when talking to doctors. Researchers analyzed conversations from an online support group and found that patients often feel their doctors don't listen to them or take their condition seriously. Interestingly, patients were careful about how they complained, trying to focus on practical issues rather than seeming like they were just complaining.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

[Functional somatic syndromes from the view of cultural anthropology].

Nakagami, Ayako, Tsujiuchi, Takuya·Nihon rinsho. Japanese journal of clinical medicine·2009

This study explains how culture and society shape the way people experience and describe illnesses like ME/CFS. The authors point out that doctors and patients often understand illness differently—doctors focus on what they can measure (disease), while patients focus on how the illness affects their daily life (illness). Understanding these different viewpoints can help doctors and patients communicate better and work together.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

[Sub-health state and chronic fatigue syndrome].

Wang, Tian-Fang, Xue, Xiao-Lin·Zhongguo Zhong xi yi jie he za zhi Zhongguo Zhongxiyi jiehe zazhi = Chinese journal of integrated traditional and Western medicine·2008

This study clarifies that 'sub-health'—a state of feeling unwell that falls short of diagnosed disease—is different from ME/CFS. The authors explain what fatigue, chronic fatigue, and ME/CFS actually are, and discuss how doctors can tell them apart using established diagnostic criteria. Understanding these differences helps ensure people with ME/CFS receive appropriate diagnosis and care.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceMethods-PaperEditor reviewed

A train-the-trainer education and promotion program: chronic fatigue syndrome--a diagnostic and management challenge.

Brimmer, Dana J, McCleary, K Kimberly, Lupton, Teresa A et al.·BMC medical education·2008

This study tested whether training primary care doctors about ME/CFS could help more patients get diagnosed and treated. Researchers trained 79 doctors and nurse practitioners to recognize and manage ME/CFS, and these trained providers then taught over 2,000 other healthcare workers. The training improved doctors' knowledge and confidence in diagnosing ME/CFS, showing that education programs can help address the problem of missed diagnoses.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryMethods-PaperEditor reviewed

Bayesian biomarker identification based on marker-expression proteomics data.

Bhattacharjee, M, Botting, C H, Sillanpää, M J·Genomics·2008

This study developed statistical methods to find biological markers (biomarkers) that could help identify and diagnose ME/CFS. The researchers used blood protein measurements and genetic information from ME/CFS patients to find which markers are most closely linked to the disease. Finding these biomarkers is important because ME/CFS is currently hard to diagnose and measure, and having reliable biological tests could change that.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryEditor reviewed

Obstructions for quality care experienced by patients with chronic fatigue syndrome (CFS)--a case study.

Gilje, Ann Marit, Söderlund, Atle, Malterud, Kirsti·Patient education and counseling·2008

This study asked 12 ME/CFS patients about their experiences with doctors and healthcare. Patients reported that doctors often didn't believe them, didn't listen carefully, or treated them dismissively. Many felt that doctors blamed their symptoms on psychological causes or didn't take them seriously, which was sometimes as painful as the illness itself.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

[History of chronic fatigue syndrome].

Hashimoto, Nobuya·Nihon rinsho. Japanese journal of clinical medicine·2007

This article reviews the history of ME/CFS, showing that conditions with similar symptoms have existed for hundreds of years under different names like neurasthenia and myalgic encephalomyelitis. A major outbreak at Lake Tahoe in the 1980s brought modern attention to the disease, but doctors realized that not all patients with CFS symptoms actually had evidence of EBV infection, suggesting the disease is more complex than a simple viral cause. The authors explain how understanding this history can help develop better diagnostic guidelines for the condition.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryEditor reviewed

[Chronic fatigue syndrome in a 15-year-old girl].

Díaz-Caneja Greciano, A, Rodríguez Sosa, J T, Aguilera Albesa, S et al.·Anales de pediatria (Barcelona, Spain : 2003)·2007

This report describes a 15-year-old girl diagnosed with ME/CFS (chronic fatigue syndrome), a condition that causes severe tiredness and lack of energy without an obvious physical cause. The doctors emphasize that ME/CFS should be considered when young people have chronic fatigue along with other symptoms but medical tests don't reveal why. Treatment focused on rehabilitation with cognitive behavioral therapy (talking therapy to address thoughts and behaviors) combined with a gradual, structured increase in activity levels.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Myalgic encephalomyelitis: a review with emphasis on key findings in biomedical research.

Hooper, M·Journal of clinical pathology·2007

This review examines what scientific research has discovered about ME/CFS, a complex illness that affects multiple body systems and causes long-lasting tiredness, pain, and other symptoms. The authors discuss not only the medical findings but also how disagreements and differing opinions among doctors and scientists have affected research and care for ME/CFS patients. They emphasize that these broader debates have real consequences for patients seeking answers and proper treatment.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceCross-SectionalEditor reviewed

The validity of an empirical delineation of heterogeneity in chronic unexplained fatigue.

Aslakson, Eric, Vollmer-Conna, Uté, White, Peter D·Pharmacogenomics·2006

Researchers used statistical methods to identify distinct groups among people with chronic unexplained fatigue, including those with ME/CFS. They tested whether these groups were real and consistent by running their analysis multiple ways. They found that the groups they identified were valid and matched well with established ME/CFS diagnostic criteria, suggesting that ME/CFS is not one single condition but rather several related conditions with potentially different underlying causes.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryEditorialEditor reviewed

Challenges for molecular profiling of chronic fatigue syndrome.

Vernon, Suzanne D, Whistler, Toni, Aslakson, Eric et al.·Pharmacogenomics·2006

This paper discusses why it's been difficult for scientists to find reliable blood tests (biomarkers) to diagnose ME/CFS and develop treatments. The authors explain that ME/CFS is complex because it affects many body systems at once, and each researcher may focus on different areas based on their expertise. They suggest that blood tests show promise for understanding ME/CFS and that combining genetic information, protein data, and information about patients' environments and behaviors could help researchers better understand why different patients experience the illness differently.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

Illnesses you have to fight to get: facts as forces in uncertain, emergent illnesses.

Dumit, Joseph·Social science & medicine (1982)·2006

This study examines why ME/CFS and multiple chemical sensitivity remain controversial and hard to get diagnosed. Researchers found that patients often struggle because doctors and institutions lack clear biological evidence for these illnesses, and they use scientific uncertainty as a reason to deny patients care and legitimacy. Patients have responded by documenting these exclusions and developing their own strategies to fight back.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeEditor reviewed

Conceptual issues in undifferentiated somatoform disorder and chronic fatigue syndrome.

van Staden, Werdie C W·Current opinion in psychiatry·2006

This paper examines why it can be difficult to distinguish between two conditions that both cause severe tiredness: undifferentiated somatoform disorder (a condition where physical symptoms occur without clear medical causes) and ME/CFS. The author argues that a key difference may be how patients experience their fatigue—some describe it as purely physical rather than mental—and that this distinction has not been properly studied or recognized in ME/CFS research.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

[Chronic fatigue syndrome].

Maoz, Daniel, Shoenfeld, Yehuda·Harefuah·2006

ME/CFS is a serious illness that causes extreme tiredness and other symptoms that interfere with daily life. Doctors often fail to diagnose it correctly, and we still don't fully understand what causes it. This review suggests that ME/CFS likely results from multiple different factors working together, and that two treatments—cognitive behavioral therapy and graded exercise therapy—might help some patients.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

[Chronic fatigue syndrome: its importance in occupational medicine].

Wiszniewska, Marta, Walusiak, Jolanta, Wittczak, Tomasz et al.·Medycyna pracy·2005

This paper reviews what we know about ME/CFS, including what causes it, how it presents in patients, and how doctors can diagnose it. Since extreme tiredness appears in many different health conditions—both physical and mental—the authors explain how doctors can tell ME/CFS apart from other illnesses. The paper also covers treatment approaches and emphasizes why occupational health doctors need to understand ME/CFS to protect workers' health.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceMethods-PaperEditor reviewed

Psychometric properties of the CDC Symptom Inventory for assessment of chronic fatigue syndrome.

Wagner, Dieter, Nisenbaum, Rosane, Heim, Christine et al.·Population health metrics·2005

Researchers created and tested a new questionnaire called the CDC CFS Symptom Inventory to help measure the many different symptoms that people with ME/CFS experience—not just fatigue, but also other important symptoms like problems with memory, sleep, and pain. They gave this questionnaire to 164 people (some with ME/CFS, some with other illnesses, and some without fatigue) and found that the questionnaire reliably distinguished people with ME/CFS from others and worked well when compared to existing fatigue measurement tools.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryMethods-PaperEditor reviewed

Improving the diagnostic criteria and procedures for chronic fatigue syndrome.

King, Caroline, Jason, Leonard A·Biological psychology·2005

Doctors have used different definitions to diagnose ME/CFS since 1988, but these definitions were never tested scientifically to see if they actually work well. This study compared 15 people with ME/CFS, 15 with depression, and 15 healthy people to find better ways to diagnose ME/CFS. The researchers found that adding new symptoms, measuring how severe symptoms are, and using specific tests could help doctors diagnose ME/CFS more accurately.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

Unloading the trunk: neurasthenia, CFS and race.

Luthra, A, Wessely, S·Social science & medicine (1982)·2004

This study examines how ME/CFS and its historical predecessor neurasthenia have been discussed in terms of race and ethnicity over the past century. The authors found that there is a pattern of thinking that associates fatigue illnesses with technological 'development' in white countries, and they explore why far fewer non-white patients appear in specialist ME/CFS clinics compared to what you might expect from the general population.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Chronic fatigue syndrome or myalgic encephalomyelitis in children and adolescents.

Chatterjee, Tapabrata·Journal of the Indian Medical Association·2003

This article reviews how ME/CFS affects children and teens, a group that is often overlooked in medical research. The authors explain the current diagnostic criteria used to identify the condition and discuss available treatments, though they note that how well these treatments work and what happens to patients over time remains unclear.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryEditorialEditor reviewed

An approach to chronic fatigue syndrome in adults.

Sabin, Thomas D·The neurologist·2003

This paper helps doctors, especially neurologists, understand how to properly evaluate patients who are experiencing severe fatigue. The author emphasizes that while ME/CFS is a real condition, it's important to rule out other medical problems that can cause similar symptoms before confirming an ME/CFS diagnosis. Since there is no blood test or scan that can definitively diagnose ME/CFS, careful evaluation and questioning of patients is essential.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceMethods-PaperEditor reviewed

Identification of ambiguities in the 1994 chronic fatigue syndrome research case definition and recommendations for resolution.

Reeves, William C, Lloyd, Andrew, Vernon, Suzanne D et al.·BMC health services research·2003

This study brought together experienced ME/CFS researchers from around the world to identify problems and confusing parts of the official definition used to diagnose ME/CFS in research studies. The team worked together in workshops over three years to find ways to make the diagnosis more consistent and accurate across different research sites, so that patients are identified the same way no matter where they're studied.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryCross-SectionalEditor reviewed

Evaluating attributions for an illness based upon the name: chronic fatigue syndrome, myalgic encephalopathy and Florence Nightingale disease.

Jason, Leonard A, Taylor, Renee R, Plioplys, Sigita et al.·American journal of community psychology·2002

This study asked medical trainees to read about a patient with ME/CFS symptoms, but gave different groups different names for the illness: "chronic fatigue syndrome," "myalgic encephalopathy," or "Florence Nightingale disease." Researchers found that the name used affected how seriously the trainees thought about the illness—specifically, "myalgic encephalopathy" sounded more serious than "chronic fatigue syndrome." This suggests that what doctors call a disease can influence how much they respect and understand it.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

[Chronic fatigue: introduction].

Ducobu, J·Revue medicale de Bruxelles·2002

This review article explains that chronic fatigue is very common in general medical practice. Doctors need to first rule out other medical conditions that cause tiredness, then look for psychological factors and chronic fatigue syndrome (CFS). The key message is that careful clinical evaluation by a doctor is more important than ordering many laboratory tests to figure out what's causing someone's fatigue.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceReview-NarrativeEditor reviewed

[Chronic fatigue syndrome. More and more differential diagnoses suggest a new view of this syndrome].

Merz, Susanne·Lakartidningen·2002

This review examines how ME/CFS is defined and diagnosed, and explains that several other medical conditions can look like ME/CFS but are actually different diseases. The authors highlight that many conditions—such as chronic infections, thyroid problems, and allergies—can cause similar symptoms to ME/CFS. They recommend that doctors carefully test patients to find the true cause of their symptoms rather than assuming everyone with severe fatigue has ME/CFS.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryCase-ControlEditor reviewed

[Symptom or illness? The exhausting life of an adolescent with chronic fatigue syndrome].

Di Gallo, A·Zeitschrift fur Kinder- und Jugendpsychiatrie und Psychotherapie·2002

This study describes the medical experience of a teenage boy diagnosed with chronic fatigue syndrome (CFS). The doctors examined questions about what causes CFS, how it develops, how to diagnose it, and what treatments might help. The case provides a detailed look at one patient's journey with this complex illness.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryMethods-PaperEditor reviewed

Generation of classification criteria for chronic fatigue syndrome using an artificial neural network and traditional criteria set.

Linder, R, Dinser, R, Wagner, M et al.·In vivo (Athens, Greece)·2002

Researchers tested whether a computer program called an artificial neural network could help doctors better identify ME/CFS by looking at patient symptoms and comparing them to two other conditions that also cause fatigue: lupus and fibromyalgia. The computer program was very accurate—correctly identifying ME/CFS about 95% of the time—and worked better than traditional statistical methods for creating diagnostic rules.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

[Chronic fatigue syndrome: the point of view of the internist].

Cogan, E·Revue medicale de Bruxelles·2002

This review examines how doctors approach patients with chronic fatigue. The authors note that most chronic fatigue cases stem from psychiatric conditions like depression and anxiety. A small group of patients have ME/CFS, which involves fatigue, mood and thinking problems, and various other physical symptoms—but doctors still don't know what causes it. Current treatments with limited evidence include antidepressants, talk therapy, and graded exercise programs.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryCross-SectionalEditor reviewed

Women's experiences of stigma in relation to chronic fatigue syndrome and fibromyalgia.

Asbring, Pia, Närvänen, Anna-Liisa·Qualitative health research·2002

This study interviewed 25 women with ME/CFS or fibromyalgia about their experiences with stigma—being doubted, judged, or not taken seriously. Women reported that stigma was most common before they received a diagnosis, and that having many different symptoms made it harder for others to believe they were truly ill. People sometimes questioned whether the illnesses were real or blamed them on emotional problems rather than physical causes.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainEditorialEditor reviewed

[Fatigue].

Reinhart, W H, Fleisch, F·Praxis·2001

Fatigue is a very common symptom that doctors see in many patients. This editorial discusses how doctors should evaluate someone with fatigue by taking a careful history, doing a physical exam, and ordering appropriate tests. When other diseases are ruled out, chronic fatigue syndrome may be diagnosed, though its causes remain unknown. The most proven treatments are graded exercise, cognitive behavioral therapy, and antidepressants if depression or anxiety are present.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

Fatigue in primary care.

Morrison, R E, Keating, H J·Obstetrics and gynecology clinics of North America·2001

Fatigue is very common and can have many different causes. Doctors can usually figure out what's causing someone's tiredness through a careful conversation, physical exam, and a few blood tests. In rare cases, people have extreme fatigue lasting 6 months or longer that doesn't have an obvious cause—this may be chronic fatigue syndrome (ME/CFS).

Diagnostics
E3 PreliminaryPEM unclearPreliminaryObservationalEditor reviewed

Doing things with illness. The micro politics of the CFS clinic.

Banks, J, Prior, L·Social science & medicine (1982)·2001

This study observed conversations between ME/CFS patients and doctors in a UK clinic to understand how they think about the condition differently. Patients and doctors often disagreed about whether ME/CFS is a disease of the body or the mind, and these disagreements shaped how treatment was discussed. The researchers found that these conversations were really about who gets to decide what ME/CFS actually is.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

Feminist perspectives on the social construction of chronic fatigue syndrome.

Richman, J A, Jason, L A, Taylor, R R et al.·Health care for women international·2000

This study compares how doctors have historically viewed ME/CFS with how patients themselves understand the illness. The researchers found that when medical science couldn't find a viral cause for ME/CFS, doctors increasingly blamed psychiatric or social factors instead of looking for biological explanations. The authors argue that discovering biological markers (measurable signs of disease) could help restore ME/CFS's credibility as a real medical condition, similar to how multiple sclerosis gained recognition.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

The challenge of evaluating fatigue.

Rodriguez, T·Journal of the American Academy of Nurse Practitioners·2000

This article helps doctors and nurse practitioners understand how to properly evaluate fatigue in patients. It explains that fatigue can have many different causes and can be either short-term or long-term, and it's important to distinguish chronic fatigue from ME/CFS. The article suggests using specific tools and checklists to help identify what might be causing someone's fatigue so it can be properly treated.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

The importance of orthostatic intolerance in the chronic fatigue syndrome.

Schondorf, R, Freeman, R·The American journal of the medical sciences·1999

This review examines how problems with standing up (orthostatic intolerance) are connected to ME/CFS. Many people with ME/CFS experience symptoms like dizziness, fatigue, trouble concentrating, shaking, and nausea when standing or sitting upright. The authors review what we know about this connection, including how to diagnose it, what tests can help, what might cause it, and how it might be treated.

Autonomic Nervous SystemDiagnostics
E3 PreliminaryPEM not requiredModerate confidenceGuidelineEditor reviewed

Social Security Ruling, SSR 99-2p.; titles II and XVI; evaluating cases involving chronic fatigue syndrome (CFS). Social Security Administration. Notice of Social Security ruling.

Federal register·1999

The Social Security Administration issued an official ruling in 1999 to help people with ME/CFS get disability benefits. The ruling states that ME/CFS is a real medical condition that can prevent someone from working, but only when doctors find specific signs or lab results that support the diagnosis. This ruling was meant to make sure all disability examiners across the country evaluate ME/CFS cases using the same fair standards.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryRegistry-ResourceEditor reviewed

The Chronic Fatigue Twin Registry: method of construction, composition, and zygosity assignment.

Buchwald, D, Herrell, R, Ashton, S et al.·Twin research : the official journal of the International Society for Twin Studies·1999

Researchers created a registry of twin pairs where at least one person had chronic fatigue to better understand the condition. They recruited 204 twin pairs through support groups, doctors, and other sources, and had 177 complete their detailed questionnaires and phone interviews. This registry was designed to help scientists study what causes chronic fatigue and whether genetics or life circumstances play a bigger role.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

Chronic fatigue syndrome: a review for clinicians.

Goshorn, R K·Seminars in neurology·1998

This review explains that ME/CFS is a real condition characterized by long-lasting fatigue, muscle and joint pain, sleep problems, and thinking difficulties. While doctors don't yet fully understand what causes ME/CFS, research suggests it involves subtle problems with the nervous system, hormones, and immune function. Treatment focuses on managing symptoms to help patients feel better, though the approach is personalized since every patient is different.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Chronic fatigue syndrome and fibromyalgia. Dilemmas in diagnosis and clinical management.

Demitrack, M A·The Psychiatric clinics of North America·1998

This article reviews what we know about ME/CFS and fibromyalgia, two conditions that cause severe tiredness and pain and are often misunderstood. The authors explain that these illnesses involve both physical and mental health factors working together, rather than being purely 'in your head' or purely physical. They provide doctors with practical guidelines for better diagnosis and treatment of these challenging conditions.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceGuidelineEditor reviewed

Chronic fatigue syndrome. A practical guide to assessment and management.

Sharpe, M, Chalder, T, Palmer, I et al.·General hospital psychiatry·1997

This guide explains how doctors should assess and manage ME/CFS by building trust with patients, taking a detailed history, and ruling out other conditions. Treatment focuses on helping patients understand their illness, establish consistent activity and sleep patterns, and gradually return to normal activities, with cognitive behavioral therapy being the only proven effective approach. The authors emphasize that ME/CFS is a real, treatable condition and provide practical strategies to help patients avoid misinterpreting their symptoms or fearing activity.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryEditorialEditor reviewed

Chronic fatigue syndrome and occupational health.

Mounstephen, A, Sharpe, M·Occupational medicine (Oxford, England)·1997

This article reviews what doctors who work in occupational health need to know about ME/CFS to help their patients. The authors discuss what ME/CFS is, what might cause it, how patients typically recover, and practical ways to diagnose and manage the condition. They argue that occupational health doctors are in a good position to help improve outcomes for people with ME/CFS, particularly by improving education, rehabilitation programs, and support for staying in or returning to work.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainEditorialEditor reviewed

Chronic fatigue syndrome: a 20th century illness?

Wessely, S·Scandinavian journal of work, environment & health·1997

This article examines how ME/CFS became recognized as a medical illness in modern times. The condition was largely unknown and unnamed until the 1980s, when it emerged under various labels including 'chronic Epstein-Barr virus syndrome' and later 'chronic fatigue syndrome.' The author discusses how different countries use different names for the condition and explores connections between ME/CFS and the concept of somatization—when stress or psychological factors manifest as physical symptoms.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

[Chronic fatigue syndrome].

van der Meer, J W·Nederlands tijdschrift voor geneeskunde·1997

This review examines different theories about what causes ME/CFS, ranging from persistent infections and metabolic problems to psychiatric factors. While many potential causes have been proposed—including lingering infections, toxins, immune system problems, nervous system dysfunction, and hormone imbalances—none have been definitively proven. The authors note that psychological factors play an important role in how the illness develops and can be helpful in treating patients.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceReview-NarrativeEditor reviewed

[Definition of "chronic fatigue syndrome" (CFS)].

Heyll, U, Wachauf, P, Senger, V et al.·Medizinische Klinik (Munich, Germany : 1983)·1997

In 1988, doctors created an official definition for chronic fatigue syndrome (CFS) to help researchers study it consistently. However, this study found that the original definition didn't work as well as hoped—it didn't capture the condition accurately, and patients with CFS turned out to be quite different from each other. The authors suggest that CFS should be understood as a descriptive condition rather than a single disease with one cause.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

Chronic fatigue syndrome: an update for clinicians in primary care.

Houde, S C, Kampfe-Leacher, R·The Nurse practitioner·1997

This article explains what ME/CFS is and how doctors can recognize it. The main challenge is that ME/CFS doesn't show up on standard tests, so doctors need to rule out other conditions first. Treatment works best when it's tailored to each person's specific symptoms and needs.

InterventionsDiagnostics
E3 PreliminaryPEM not requiredPreliminaryCase-ControlEditor reviewed

[Chronic fatigue--'tired with 23 i's'].

van der Meer, J W, Elving, L D·Nederlands tijdschrift voor geneeskunde·1997

This study describes two patients with severe tiredness. One woman had chronic fatigue syndrome and improved slowly over time, while one man's exhaustion was caused by a treatable pituitary gland tumor that was removed surgically. The doctors emphasize that it's important to thoroughly examine patients to find out if something else is causing their tiredness before diagnosing chronic fatigue syndrome.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainGuidelineEditor reviewed

[Indications for management in long-term, physically unexplained fatigue symptoms].

van der Meer, J W, Rijken, P M, Bleijenberg, G et al.·Nederlands tijdschrift voor geneeskunde·1997

This guideline, developed by Dutch doctors and health officials, suggests that chronic fatigue lasting more than 6 months without a clear medical cause should be managed differently depending on how long someone has had it. Rather than continuously searching for hidden causes, patients are encouraged to gradually rebuild activity using a structured schedule and focus on overall health promotion.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

[Chronic fatigue syndrome. Definition, diagnostic measures and therapeutic possibilities].

Lieb, K, Dammann, G, Berger, M et al.·Der Nervenarzt·1996

ME/CFS is a disorder that causes persistent tiredness, but doctors cannot diagnose it with a simple blood test or scan. Instead, doctors use specific clinical criteria to identify the condition, while carefully ruling out other illnesses like depression or sleep problems that can look similar. Currently, there is no cure for ME/CFS, so treatment focuses on managing individual symptoms like poor sleep, pain, and mood changes with a combination of medical care and psychological support.

Pain and SensitizationSleepDiagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

The history and treatment of chronic fatigue syndrome.

Ross, E·Nursing times·1996

This article reviews the history of chronic fatigue syndrome (ME/CFS) and how it has been treated over time. ME/CFS is a real illness that affects 1 to 2.5 out of every 100 people. The article explains what doctors look for when diagnosing ME/CFS and describes the important role nurses play in helping patients manage and treat their condition.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceGuidelineEditor reviewed

Chronic fatigue syndrome. Summary of a report of a joint committee of the Royal Colleges of Physicians, Psychiatrists and General Practitioners.

Wessely, S·Journal of the Royal College of Physicians of London·1996

This report from major medical colleges explains that ME/CFS is not caused by a single problem, but rather results from many different factors working together. The condition develops differently in different people, depending on what triggered it initially, what made them vulnerable to it, and what keeps it going. Understanding all these different pieces is important for helping patients recover.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainCase-ControlEditor reviewed

Chronic fatigue syndrome and dieting disorders: diagnosis and management problems.

Griffiths, R A, Beumont, P J, Moore, G M et al.·The Australian and New Zealand journal of psychiatry·1996

This study looked at three patients who were diagnosed with ME/CFS but also had eating disorders (anorexia nervosa or bulimia nervosa). The doctors found that proper screening for eating disorders is important because patients and families may focus on the ME/CFS diagnosis and miss the eating disorder, which delays appropriate treatment. Early identification of both conditions together can help reduce serious health problems.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceReview-NarrativeEditor reviewed

Chronic fatigue syndrome.

Sharpe, M·The Psychiatric clinics of North America·1996

ME/CFS is a serious illness that causes extreme tiredness, difficulty concentrating, muscle pain, and other physical symptoms that doctors cannot fully explain with standard tests. This review explains that ME/CFS involves both real physical changes in the body and emotional or social factors that affect how someone experiences the illness. The best approach to treating ME/CFS is to carefully assess each person's unique situation rather than debating whether it's purely medical or psychiatric.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceGuidelineEditor reviewed

Chronic fatigue syndrome: current perspectives on evaluation and management.

Hickie, I B, Lloyd, A R, Wakefield, D·The Medical journal of Australia·1995

This guideline helps doctors evaluate and treat ME/CFS by reviewing what we know about the condition. The authors found that while many medical and psychological factors can affect recovery, no single infection has been proven to cause ME/CFS. Treatment works best when doctors address all aspects of a patient's health—physical, mental, and social—rather than focusing on just one area.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainGuidelineEditor reviewed

Chronic fatigue syndrome. Committee for Science and Education, Medical Association of South Africa.

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde·1995

A group of South African medical experts created guidelines to help doctors recognize and treat chronic fatigue syndrome (CFS). The guidelines outline what symptoms and test results might help diagnose CFS, and suggest reasonable ways to manage the condition while keeping costs reasonable. However, the experts disagreed significantly about whether CFS is a real, distinct illness.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

[Chronic fatigue syndrome].

Trinidad, E E, Ramírez-Ronda, C·Boletin de la Asociacion Medica de Puerto Rico·1994

Chronic Fatigue Syndrome (ME/CFS) is a long-lasting illness that causes extreme tiredness and affects an estimated 24% of people. It was officially defined as a medical condition in 1988 after doctors recognized increasing numbers of patients with similar symptoms. The condition is more common in women aged 20-50 and is currently treated with supportive care to help manage symptoms.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryEditorialEditor reviewed

[Chronic fatigue syndrome and psychiatric diseases].

Matsuno, T, Hikita, K, Matsuo, T·Nihon rinsho. Japanese journal of clinical medicine·1994

This 1994 commentary discusses whether ME/CFS is actually a form of depression or a separate condition. The authors argue that ME/CFS is genuinely different from depression because people with ME/CFS remain motivated and don't show the emotional numbness seen in depression. Instead, ME/CFS involves fatigue that fluctuates sharply, along with persistent physical symptoms like malaise and low fevers.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

[Chronic fatigue syndrome].

Sternon, J, Decaux, G, Hoffmann, G·Revue medicale de Bruxelles·1994

This paper describes how doctors can diagnose ME/CFS using specific criteria and discusses what might cause the condition. The authors note that viral infections may trigger ME/CFS, and that anxiety or depression can make symptoms worse. Importantly, they found that some patients improve on their own after a few years, though most don't respond well to available treatments.

SleepDiagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

[Chronic fatigue syndrome: a critical review].

Cathébras, P, Bouchou, K, Charmion, S et al.·La Revue de medecine interne·1993

ME/CFS is a debilitating condition characterized mainly by extreme tiredness of unknown cause. Current diagnostic criteria don't clearly identify a single uniform group of patients, and no clear infectious or immune cause has been definitively proven, though some viruses and immune changes may play a role in some cases. Treatment options are limited but may include antidepressants and cognitive-behavioral therapy.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainEditorialEditor reviewed

Chronic fatigue syndrome. A fresh look at an old problem.

McSherry, J·Canadian family physician Medecin de famille canadien·1993

This editorial discusses chronic fatigue syndrome (ME/CFS) as a real medical condition affecting about 3 in 100,000 people. Most patients experience symptoms for approximately 2.5 years before recovering to normal health. Since there is no single definitive test, doctors diagnose ME/CFS by ruling out other diseases, and currently no one treatment works for everyone.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryEditorialEditor reviewed

Somatization, illness attribution and the sociocultural psychiatry of chronic fatigue syndrome.

Abbey, S E·Ciba Foundation symposium·1993

This paper explores how psychological factors, personal beliefs about illness, and social influences may play a role in ME/CFS. The author examines how things like perfectionism, how people cope with stress, and the way doctors and media talk about ME/CFS can affect whether someone develops the condition or how severe their symptoms become.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

Treatment of the chronic fatigue syndrome. A review and practical guide.

Blondel-Hill, E, Shafran, S D·Drugs·1993

This 1993 guide explains that ME/CFS is a real illness defined by severe, disabling fatigue along with other physical and mental symptoms, though its exact cause remains unknown. The main treatment is getting a proper diagnosis, learning about the condition, and working with a caring doctor who understands it. Some patients may benefit from antidepressant medications even without depression, though no single treatment has been proven to work reliably for everyone.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

[Chronic fatigue syndrome--symptoms, signs, laboratory tests, and prognosis].

Kanayama, Y·Nihon rinsho. Japanese journal of clinical medicine·1992

This review article describes the main symptoms and characteristics of ME/CFS, including persistent fatigue lasting more than 6 months, low-grade fevers, swollen lymph nodes, muscle and joint pain, and mood-related symptoms. Since no specific blood test or scan can definitively diagnose ME/CFS, doctors must rule out other known causes of fatigue before making the diagnosis. The underlying cause remains unknown, though researchers suspect it may involve an infection combined with psychological factors.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

Chronic fatigue syndrome.

Klonoff, D C·Clinical infectious diseases : an official publication of the Infectious Diseases Society of America·1992

ME/CFS is a complex illness characterized by persistent fatigue and other symptoms, but doctors currently have no blood test or scan to diagnose it—they rely instead on what patients report. Research has identified that several factors may increase risk of developing ME/CFS, including viral infections, mental health conditions, and allergies, and studies show problems across multiple body systems including immune, nervous, hormone, and muscle function. While there is no cure yet, treatments like exercise, counseling, and medications can help manage some symptoms.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

[Definition of the chronic fatigue syndrome and its issues].

Hashimoto, N·Nihon rinsho. Japanese journal of clinical medicine·1992

This article reviews how ME/CFS was officially defined by the CDC in 1988 and identifies problems with that definition. The author points out that while the definition tries to rule out other conditions, it has trouble distinguishing ME/CFS from similar conditions like fibromyalgia and depression, and it's difficult to measure in real-world clinical practice.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

Chronic fatigue syndrome. A review from the general practice perspective.

Holmwood, C, Shannon, C·Australian family physician·1992

This 1992 editorial confirms that ME/CFS is a real condition that significantly impacts people's quality of life, though the exact cause was not yet known. The authors suggest that treatment should focus on supportive counseling, explanation of the condition, psychiatric support when needed, and gradually increasing activity levels to help people return to normal functioning.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryMethods-PaperEditor reviewed

[Diagnostic criteria for chronic fatigue syndrome by the CFS Study Group in Japan].

Kitani, T, Kuratsune, H, Yamaguchi, K·Nihon rinsho. Japanese journal of clinical medicine·1992

In 1992, Japanese researchers created new diagnostic guidelines to help doctors identify ME/CFS in their patients. These guidelines were based on earlier American standards but included some modifications, such as defining less severe cases and recognizing a form that develops after infections.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryObservationalEditor reviewed

[Chronic fatigue syndrome--51 cases in the Jikei University School of Medicine].

Hashimoto, N, Kuraishi, Y, Yokose, T et al.·Nihon rinsho. Japanese journal of clinical medicine·1992

This study identified 51 patients with ME/CFS diagnosed using official CDC criteria between 1991 and 1992. Most patients were women in their 20s–30s who had been seen by many doctors before receiving a correct diagnosis. Standard blood tests did not reveal abnormal findings, though some immune markers were mildly abnormal. About 57% of patients showed general improvement, and doctors used various medications to manage severe symptoms.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

Chronic fatigue syndrome. Recent advances in diagnosis and treatment.

Bell, D S·Postgraduate medicine·1992

ME/CFS typically starts suddenly with severe tiredness and flu-like symptoms that come and go over months or years. While blood tests sometimes show immune system changes, doctors diagnose ME/CFS mainly by recognizing the pattern of symptoms and ruling out other illnesses. Current treatment focuses on managing symptoms and helping patients cope with this long-lasting, disabling condition.

InterventionsDiagnostics
E3 PreliminaryPEM not requiredWeak / uncertainEditorialEditor reviewed

Chronic fatigue syndrome: is it real?

Kroenke, K·Postgraduate medicine·1991

This 1991 editorial discusses what doctors understood about ME/CFS at that time. The author suggests that ME/CFS is likely connected to depression, mild immune system problems, or a combination of both, rather than being caused by Epstein-Barr virus alone. The article recommends that doctors use careful patient interviews, physical exams, and basic blood tests to diagnose the condition, and that supportive, hopeful care is important for treatment.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryMethods-PaperEditor reviewed

Issues and problems in the conduct of epidemiologic research on chronic fatigue syndrome.

Grufferman, S·Reviews of infectious diseases·1991

This paper discusses how scientists should study ME/CFS using epidemiology—a research method that looks at how diseases spread through populations. The authors outline the main problems researchers face when studying ME/CFS, such as unclear diagnostic criteria and limited understanding of the condition, and suggest practical solutions. They emphasize that case-control studies (comparing people who have ME/CFS with similar people who don't) should be a priority for understanding what causes the illness.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

Definition and measurement of fatigue.

Barofsky, I, Legro, M W·Reviews of infectious diseases·1991

This paper examines how fatigue is defined and measured in ME/CFS, highlighting that these definitions have not been well-developed in medical research. The authors reviewed different tools available to measure fatigue—ranging from simple single-item questions to more complex multi-part assessments—and discussed how fatigue in ME/CFS differs from fatigue studied in healthy people in laboratory settings. They emphasize the need to study fatigue as it actually occurs in patients with ME/CFS and to use consistent measurement methods across research.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

[Chronic fatigue: myth or reality?].

Comtois, R·L'union medicale du Canada·1991

This 1991 review article addresses a fundamental question: Is chronic fatigue a real medical condition or just a perception? The authors acknowledge that while fatigue is one of the most common health complaints doctors hear, it can be difficult to diagnose and treat because we don't have simple blood tests like we do for cholesterol. The paper discusses how new diagnostic criteria for chronic fatigue syndrome were beginning to help doctors identify and manage this condition more effectively.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

Evaluation and management of patients with chronic fatigue.

Matthews, D A, Manu, P, Lane, T J·The American journal of the medical sciences·1991

This review article examines how doctors diagnose and treat patients who experience chronic fatigue in everyday medical practice. The authors note that chronic fatigue has many possible causes, including medical illnesses, psychiatric conditions like depression and anxiety, lifestyle factors, and medications. They emphasize that building trust with patients and using a combination of psychiatric evaluation, functional assessment, and both medication and behavioral therapy approaches are important for effective care.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainEditorialEditor reviewed

Neurasthenia in the 1980s: chronic mononucleosis, chronic fatigue syndrome, and anxiety and depressive disorders.

Greenberg, D B·Psychosomatics·1990

In the 1980s, doctors thought chronic fatigue syndrome might be caused by a virus called Epstein-Barr virus (the virus that causes mononucleosis). This editorial explains that while this seemed like a logical explanation, the virus is not actually the cause of chronic fatigue syndrome. The author points out that many people with chronic fatigue also have depression or anxiety, and notes that these mental health conditions should be carefully evaluated and treated rather than overlooked.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainEditorialEditor reviewed

[Chronic fatigue syndrome--a new disease picture?].

Nix, W A·Der Nervenarzt·1990

This editorial from 1990 discusses that ME/CFS was becoming more commonly diagnosed at that time, but doctors weren't sure if it was one distinct disease or simply a label given to many different conditions. The author notes that we still need to understand whether ME/CFS has a physical cause, a psychological cause, or both, and that each patient may need individual evaluation.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Old wine in new bottles: neurasthenia and 'ME'.

Wessely, S·Psychological medicine·1990

This paper compares ME/CFS with an older condition called neurasthenia that was common in the late 1800s and early 1900s. Both illnesses share similar symptoms of extreme fatigue and were popular diagnoses when people believed they were caused by physical (not mental) problems and affected successful, hardworking people. The author argues that understanding ME/CFS requires looking at both brain biology and social factors, not just one or the other.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

Chronic fatigue syndrome. A critical appraisal of the role of Epstein-Barr virus.

Koo, D·The Western journal of medicine·1989

Early research suggested that a virus called Epstein-Barr virus (EBV) might cause ME/CFS, leading to the disease sometimes being called "chronic EBV syndrome." However, this review shows that the antibody levels used to detect EBV exposure are similar in people with ME/CFS, healthy people, and people with other illnesses, making it impossible to prove EBV actually causes the condition. Since most people have been exposed to EBV at some point, we cannot easily tell whether the virus causes ME/CFS or if people with ME/CFS simply show different antibody patterns because they are already sick.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryMethods-PaperEditor reviewed

Chronic fatigue syndrome: a working case definition.

Holmes, G P, Kaplan, J E, Gantz, N M et al.·Annals of internal medicine·1988

This landmark 1988 paper proposed a new name and formal definition for what was previously called 'chronic Epstein-Barr virus syndrome.' The authors recognized that the condition was poorly understood and inconsistently diagnosed, so they renamed it 'chronic fatigue syndrome' (ME/CFS) and created a working definition to help doctors identify and study it more consistently. This definition focused on severe, ongoing fatigue along with other symptoms like sore throat, headaches, and muscle pain.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

Chronic fatigue syndrome--a diagnosis for consideration.

Portwood, M F·The Nurse practitioner·1988

This article helps doctors recognize ME/CFS by describing its many symptoms, which can range from mild tiredness to severe disability. Patients often report feeling exhausted, achy, and unable to concentrate, yet standard medical tests often appear normal. The article emphasizes that doctors should take these symptoms seriously and help patients manage their condition, even though there is currently no cure.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

The chronic fatigue syndrome (myalgic encephalomyelitis)--myth or mystery?

Spracklen, F H·South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde·1988

This 1988 review article discusses chronic fatigue syndrome (also called myalgic encephalomyelitis) and explains why there has been so much confusion about this condition. The author reviews what doctors know about the illness, including its possible causes and symptoms, and discusses why having a clear definition of the disease is important for research and treatment. The article emphasizes that better understanding and more rigorous studies are needed to help patients.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

The myalgic encephalomyelitis syndrome.

Murdoch, J C·Family practice·1988

This review examines myalgic encephalomyelitis (ME), a relapsing illness that primarily affects young women and causes severe muscle pain and exhaustion. The authors looked at research from the United Kingdom, United States, and New Zealand over 40 years to understand what might cause this condition. They discuss how difficult it is to treat patients when doctors don't know what's causing the illness, and suggest renaming it 'myalgic exhaustion syndrome.'

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceCross-SectionalEditor reviewed

["Ultimately, you are on your own." A qualitative analysis of barriers to health care from the perspective of patients with long COVID].

Hammer, Sabine, Monaca, Clara, Hoelz, Annika et al.·Zeitschrift fur Evidenz, Fortbildung und Qualitat im Gesundheitswesen·2025

This study asked 264 long COVID patients about their experiences with doctors and healthcare services. Most patients reported that healthcare providers don't understand their condition, often dismiss it as psychological, and sometimes recommend treatments that make them sicker. Patients felt stigmatized and unsupported, with some waiting up to two years just to see a specialist.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Developing a clinical-pathological framework of long COVID-related fatigue applied to public safety workers.

Lofrano-Porto, Adriana, D'Isabel, Susanne, Smith, Denise L·Frontiers in medicine·2024

This article reviews what we know about long COVID fatigue, especially in firefighters and other public safety workers. The authors explain why fatigue after COVID is so hard to diagnose and treat, since patients often look healthy on the outside even though they feel extremely tired. They describe possible biological reasons for this fatigue and discuss why it matters for workers whose jobs require them to be physically and mentally alert.

DiagnosticsLong COVID Overlap
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

Post-COVID-19 syndrome: epidemiology, diagnostic criteria and pathogenic mechanisms involved.

Carod-Artal, F J·Revista de neurologia·2021

Many people who have had COVID-19, even mild cases, don't fully recover and experience long-lasting symptoms for months afterward. This article reviews what we know about post-COVID-19 syndrome, including who gets it, what symptoms they have, and what might be causing it. Common symptoms include fatigue, breathing problems, difficulty concentrating, anxiety, and depression. The exact biological reasons why this happens are still unknown, though experts think abnormal immune and inflammatory responses may play a role.

DiagnosticsCognitive Impairment
E3 PreliminaryPEM not requiredModerate confidenceReview-NarrativeEditor reviewed

[An emerging cause of chronic fatigue and pain : post-COVID-19 condition or long COVID].

El Moussaoui, Majdouline, Guiot, Julien, Frippiat, Frédéric et al.·Revue medicale de Liege·2023

Some people who had COVID-19 develop long-lasting symptoms months or years after infection, a condition called long COVID. These symptoms include severe fatigue, muscle pain, shortness of breath, and neurological problems that are similar to those seen in ME/CFS. This review examines what we know about who develops long COVID, what causes it, and how doctors currently diagnose and treat it.

Diagnostics
E3 PreliminaryPEM requiredModerate confidenceMethods-PaperEditor reviewed

What Long COVID investigators can learn from four decades of ME/CFS research.

Jason, Leonard A, Natelson, Benjamin H, Bonilla, Hector et al.·Brain behavior and immunity integrative·2023

This article reviews 40 years of research on ME/CFS to provide guidance for scientists studying Long COVID. The authors explain how ME/CFS researchers have developed reliable ways to diagnose the illness, define symptoms, and measure severity—lessons that can help Long COVID researchers do the same. By learning from ME/CFS experience, Long COVID researchers may be able to diagnose patients earlier, understand what causes the illness, and find treatments that actually work.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryCross-SectionalEditor reviewed

Myalgic encephalomyelitis/chronic fatigue syndrome and fibromyalgia are indistinguishable by their cerebrospinal fluid proteomes.

Schutzer, Steven E, Liu, Tao, Tsai, Chia-Feng et al.·Annals of medicine·2023

Researchers examined the fluid surrounding the brain and spinal cord in people with ME/CFS—some of whom also had fibromyalgia and some who did not. Using advanced technology to measure thousands of proteins in this fluid, they found no significant differences between the two groups. This suggests that ME/CFS and fibromyalgia may not be completely separate diseases, but rather may overlap or be related conditions.

Diagnostics
E3 PreliminaryPEM requiredModerate confidenceMethods-PaperEditor reviewed

The Hindi Version of International Consensus Criteria: A Cross-cultural Adaptation and Validation Study for Myalgic Encephalomyelitis in Post-COVID Patients.

Shah, Mansi, Kakar, Atul, Gogia, Atul·The Journal of the Association of Physicians of India·2022

This study created and tested a Hindi-language version of a tool that doctors use to diagnose ME/CFS. Researchers translated the original English diagnostic criteria into Hindi and verified that it works just as well for Hindi-speaking patients in India. This makes it easier for more people to be accurately identified and diagnosed with ME/CFS, rather than being told they simply have fatigue from long COVID.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceMethods-PaperEditor reviewed

A common language for Gulf War Illness (GWI) research studies: GWI common data elements.

Cohen, Devra E, Sullivan, Kimberly A, McNeil, Rebecca B et al.·Life sciences·2022

This study created a standardized checklist of symptoms and tests that researchers should use when studying Gulf War Illness (GWI). Experts, veterans, and doctors worked together to decide which questions and measurements are most important to collect consistently across different research studies. This approach was based on a similar checklist already created for ME/CFS, allowing both conditions to use comparable research methods. Having this common language helps different research teams share and compare their findings more easily.

Diagnostics
E3 PreliminaryPEM requiredPreliminaryReview-NarrativeEditor reviewed

[Long COVID: Is it really myalgic encephalomyelitis? Bibliographic review and considerations].

Espinosa Rodríguez, P, Martínez Aguilar, A, Ripoll Muñoz, M P et al.·Semergen·2022

This review examines whether long COVID (prolonged symptoms after COVID-19 infection) might actually be myalgic encephalomyelitis (ME/CFS). The authors found striking similarities between long COVID symptoms and the diagnostic criteria used to identify ME/CFS. They recommend that patients with ongoing symptoms after COVID-19 receive blood tests, chest imaging, and long-term medical follow-up to monitor for potential chronic illness development.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryCross-SectionalEditor reviewed

"I Just Want to Feel Safe Going to a Doctor": Experiences of Female Patients with Chronic Conditions in Australia.

Merone, Lea, Tsey, Komla, Russell, Darren et al.·Women's health reports (New Rochelle, N.Y.)·2022

This study interviewed 20 Australian women with various chronic conditions, including chronic fatigue syndrome, to understand their experiences with doctors and the healthcare system. The women reported that their pain and exhaustion were often dismissed or not taken seriously, which created fear and trauma around seeking medical care. The researchers found that women with chronic illnesses need doctors who are more knowledgeable, understanding, and empathetic about their conditions.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryEditor reviewed

Understanding Patient-Provider Interaction, Treatment Acceptance, and Outcomes in Medically Unexplained Symptoms.

Bellman, Val, Zolnikov, Tara Rava·Cureus·2022

This study looked at how people with medically unexplained symptoms (MUS)—long-lasting health problems that doctors cannot identify through standard tests—experience their illness and interact with healthcare providers. Researchers interviewed patients to understand their daily struggles, frustrations with the medical system, and how healthcare experiences sometimes made things worse. The study found that patients often feel dismissed, misunderstood, and disabled by their conditions, and that better communication and training for doctors could help improve care.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainEvidence-MapEditor reviewed

[What scientific evidence do the current classifications have in order to assess occupational disability in patients with central sensitisation syndrome?].

Regal Ramos, R J·Semergen·2020

This study looked at whether doctors have good, scientific ways to measure how much ME/CFS and related conditions limit a person's ability to work. The researchers found that while many different rating systems exist, none of them have strong enough evidence to be considered reliable. This is a significant problem because patients need fair, consistent methods to document their disability for work accommodations and benefits.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryEditor reviewed

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Fibromyalgia: Definitions, Similarities, and Differences.

Natelson, Benjamin H·Clinical therapeutics·2019

This article examines whether ME/CFS and fibromyalgia are the same illness or two different conditions. The author reviews existing research and concludes that while these conditions share some similarities, they appear to be distinct illnesses with different underlying causes. If they truly are different, it would mean doctors may eventually need different treatment approaches for each condition.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Impact of Polypharmacy on Candidate Biomarker miRNomes for the Diagnosis of Fibromyalgia and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Striking Back on Treatments.

Almenar-Pérez, Eloy, Sánchez-Fito, Teresa, Ovejero, Tamara et al.·Pharmaceutics·2019

This study looked at how medicines commonly taken by fibromyalgia and ME/CFS patients might interfere with blood tests that could help diagnose these conditions. The researchers found that many prescription drugs can affect small molecules in the body called microRNAs, which are being studied as potential diagnostic markers. This means that when researchers try to identify disease-specific biomarkers, they may be picking up drug effects instead of actual disease signatures.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainEditorialEditor reviewed

[Environmental medical syndromes].

Wiesmüller, Gerhard A, Hornberg, Claudia·Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz·2017

This editorial discusses several conditions that seem related to environmental exposures and stress, including ME/CFS, fibromyalgia, and multiple chemical sensitivities. The authors explain that we don't yet fully understand what causes these conditions or how to diagnose and treat them properly. They emphasize that doctors should take patients seriously and help them even while research continues to find answers.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryCase-ControlEditor reviewed

Mitochondrial Myopathy in Follow-up of a Patient With Chronic Fatigue Syndrome.

Galán, Fernando, de Lavera, Isabel, Cotán, David et al.·Journal of investigative medicine high impact case reports·2015

This case study describes a patient who was initially diagnosed with chronic fatigue syndrome (CFS) but was later found to have a different condition called mitochondrial myopathy—a disease affecting the energy-producing structures in muscle cells. Testing showed the patient had severe deficiencies in certain components of these energy-producing structures, and genetic analysis revealed mutations inherited from the mother. The patient and family members improved significantly with high-dose vitamins B1 and B2.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainEditorialEditor reviewed

Fibromyalgia and chronic fatigue syndrome: management issues.

Bourke, Julius·Advances in psychosomatic medicine·2015

This article discusses how fibromyalgia and ME/CFS are common conditions that were previously dismissed or not taken seriously by doctors, causing patients significant suffering. Recent scientific discoveries have improved our understanding of how these conditions work in the body and what treatments may help. While complete recovery is not common, moderate improvements in symptoms and quality of life are achievable with proper management.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

[Fatigue syndromes--an overview of terminology, definitions and classificatory concepts].

Dörr, Johanna, Nater, Urs·Psychotherapie, Psychosomatik, medizinische Psychologie·2013

This article reviews how doctors classify and differentiate between different fatigue conditions, including ME/CFS, burnout, and an older condition called neurasthenia. The authors found that while these conditions share some symptoms, they have important differences—but there currently isn't enough research to clearly separate them. Depression often occurs alongside ME/CFS and burnout, making diagnosis more complicated.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceMethods-PaperEditor reviewed

The Hebrew version of the FibroFatigue scale: validation of a questionnaire for assessment of fibromyalgia and chronic fatigue syndrome.

Ablin, Jacob N, Odes, Lisa, Neumann, Lily et al.·Rheumatology international·2010

This study tested whether a Hebrew-language questionnaire called the FibroFatigue Scale (FFS) accurately measures symptoms in fibromyalgia patients. Researchers gave 100 patients with fibromyalgia this questionnaire along with other standard symptom-measuring tools, and found that the FFS reliably detected and measured how severe their symptoms were.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeEditor reviewed

Fibromyalgia: pathogenetic, diagnostic and therapeutic concerns.

Podolecki, Tomasz, Podolecki, Andrzej, Hrycek, Antoni·Polskie Archiwum Medycyny Wewnetrznej·2009

Fibromyalgia is a condition causing widespread muscle and joint pain that affects many people worldwide. This review examines what we know about fibromyalgia's causes, how doctors diagnose it, and how it can be treated. The authors note that fibromyalgia likely results from multiple factors involving the nervous system, brain chemistry, and immune function, and that treatment typically involves antidepressants, therapy, and other approaches.

Pain and SensitizationDiagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Explanatory and pragmatic perspectives regarding idiopathic physical symptoms and related syndromes.

Engel, Charles C·CNS spectrums·2006

This paper discusses two different ways to approach studying and treating illnesses like ME/CFS that don't have a clear, well-understood cause. One approach focuses on finding the root cause in controlled settings; the other focuses on whether treatments actually work in real-world patient care. The authors argue that for conditions like ME/CFS, the practical approach—focusing on what helps patients in everyday life—may be more useful than searching for a single underlying cause.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryCross-SectionalEditor reviewed

Urinary electrophoretic profiles from chronic fatigue syndrome and chronic fatigue syndrome/fibromyalgia patients: a pilot study for achieving their normalization.

Casado, Begoña, Zanone, Chiara, Annovazzi, Laura et al.·Journal of chromatography. B, Analytical technologies in the biomedical and life sciences·2005

Researchers collected urine samples from people with ME/CFS, people with ME/CFS plus fibromyalgia, and healthy controls to look for chemical differences. Using a specialized lab technique called electrophoresis, they found that the urine samples from people with these conditions showed distinct patterns of chemicals compared to healthy people. These patterns might potentially be used as biological markers to help identify and understand these illnesses.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeEditor reviewed

Evaluation and management of medically unexplained physical symptoms.

Richardson, Ralph D, Engel, Charles C·The neurologist·2004

This article reviews research on medically unexplained physical symptoms (MUPS)—symptoms that persist without clear diagnosis. The authors note that conditions like ME/CFS, fibromyalgia, and others may be more similar than different, and suggest that helpful treatment involves working closely with doctors to gradually increase activity and develop healthy coping strategies rather than relying only on medications.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Patient activism and the struggle for diagnosis: Gulf War illnesses and other medically unexplained physical symptoms in the US.

Zavestoski, Stephen, Brown, Phil, McCormick, Sabrina et al.·Social science & medicine (1982)·2004

This study looks at how Gulf War veterans and patients with conditions like ME/CFS, fibromyalgia, and chemical sensitivity have struggled to get their illnesses recognized as real by doctors. The researchers found that getting a diagnosis depends on several factors: whether the medical community accepts the diagnosis, whether patients themselves believe in it, how much uncertainty exists about what causes it, and how organized patients are in pushing for recognition. The authors suggest that doctors may need to accept that some illnesses may not have a clear cause, and that listening to what patients experience is just as important as finding a cause.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceReview-NarrativeEditor reviewed

Chiari type I malformation: overview of diagnosis and treatment.

Nash, John, Cheng, Joseph S, Meyer, Glenn A et al.·WMJ : official publication of the State Medical Society of Wisconsin·2002

Chiari Type I malformation is a condition where brain tissue extends into the spinal canal, potentially causing compression and various neurological symptoms. This review explains how doctors diagnose it using MRI imaging and discusses treatment options. The authors note that Chiari I symptoms can overlap significantly with ME/CFS and fibromyalgia, making diagnosis challenging, and they highlight controversy around whether surgery is appropriate for patients with these overlapping conditions.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryEditorialEditor reviewed

Environmental factors in medically unexplained symptoms and related syndromes: the evidence and the challenge.

Kipen, Howard M, Fiedler, Nancy·Environmental health perspectives·2002

This paper discusses how many patients experience symptoms that doctors cannot easily explain, and how these symptoms sometimes get organized into syndrome names like chronic fatigue syndrome. The authors note that these syndromes are defined only by how patients feel, not by medical tests, and that arguments continue about whether environmental factors cause them. They call for better research and clearer definitions to help both doctors and patients understand these conditions.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainEditorialEditor reviewed

[Syndromes in environmental medicine: variants of somatoform disorders].

Wiesmüller, G A, Ebel, H, Hornberg, C·Fortschritte der Neurologie-Psychiatrie·2001

This editorial discusses several conditions related to environmental sensitivities and stress, including ME/CFS, that doctors often struggle to diagnose or treat. The authors note that these conditions may result from a mix of environmental exposures, personal traits, stress, and how the mind interprets these experiences. They emphasize that while doctors don't yet have solid scientific ways to diagnose or treat these conditions, patients' symptoms deserve to be taken seriously.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Fibromyalgia, chronic fatigue syndrome, and myofascial pain syndrome.

Goldenberg, D L·Current opinion in rheumatology·1997

This review examines three related conditions—fibromyalgia, ME/CFS, and myofascial pain syndrome—and discusses ongoing challenges in diagnosing and treating them. The study found that psychiatric conditions are not a core feature of these diseases, but rather reflect that people with these conditions are more likely to seek medical help. The researchers identified that a blood pressure problem called neurally mediated hypotension may play a role in ME/CFS, and that treating patients in multidisciplinary groups (rather than in isolation) showed more promise than traditional individual treatments.

Autonomic Nervous SystemDiagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

[Endocrinopathy in the differential diagnosis of chronic fatigue syndrome].

Sterzl, I, Zamrazil, V·Vnitrni lekarstvi·1996

This review discusses how disorders of the endocrine system (hormone-producing glands) can cause fatigue and other symptoms that overlap with ME/CFS, making them difficult to distinguish. The authors highlight that some patients initially thought to have ME/CFS actually have treatable hormone conditions, particularly autoimmune thyroid disease or other glandular disorders. They also explore how problems with the stress-hormone system (the hypothalamus-pituitary-adrenal axis) might play a role in both endocrine disease and ME/CFS.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryEditorialEditor reviewed

Fibromyalgia, chronic fatigue syndrome, and myofascial pain syndrome.

Goldenberg, D L·Current opinion in rheumatology·1994

This 1994 review examined three related conditions—fibromyalgia, ME/CFS, and myofascial pain syndrome—that often overlap and remain poorly understood. The author noted that these conditions frequently occur alongside Lyme disease and other medical or psychiatric illnesses. New research at that time suggested that problems with how the central nervous system (the brain and spinal cord) processes signals might play a role in fibromyalgia and ME/CFS.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryEditorialEditor reviewed

Fibromyalgia, chronic fatigue syndrome, and myofascial pain syndrome.

Goldenberg, D L·Current opinion in rheumatology·1991

This review examines three related conditions—fibromyalgia, chronic fatigue syndrome, and myofascial pain—that often occur together and cause pain, tiredness, and sleep problems. Researchers are discovering that these conditions may share common biological causes involving how the body senses pain, hormone imbalances, and problems with muscle function. Unfortunately, the new treatments being tested at that time were not particularly effective.

Pain and SensitizationSleepDiagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Confounding features of the fibromyalgia syndrome: a current perspective of differential diagnosis.

Bennett, R M·The Journal of rheumatology. Supplement·1989

This article discusses how fibromyalgia syndrome can be confused with many other conditions, including chronic fatigue syndrome, because they share similar symptoms like pain and tiredness. When doctors misdiagnose fibromyalgia or take too long to identify it, patients may receive wrong treatments and become frustrated with their care. Understanding the differences between these conditions is important so patients get the correct diagnosis and appropriate help.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryCase-ControlEditor reviewed

[Fatigue Doesn't Always have to be caused by SARS-CoV-2: Case Report].

Howanietz, Helmuth, Graf, Ulrike, Kainz, Theresa·Padiatrie und Padologie·2022

This case report describes a 17-year-old girl who experienced severe fatigue caused by Epstein-Barr virus (EBV) infection, commonly known as infectious mononucleosis. The authors highlight that fatigue in young people can come from many different causes, not just COVID-19, and that it's important to identify the correct cause. Notably, about 13.5% of people who have EBV infection go on to develop ME/CFS, making proper diagnosis essential.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryGuidelineEditor reviewed

[Persistent fatigue following Q fever].

Keijmel, Stephan P, Morroy, Gabriëlla, Delsing, Corine E et al.·Nederlands tijdschrift voor geneeskunde·2012

After a bacterial infection called Q fever, about 1 in 5 patients develop long-lasting fatigue and other symptoms called Q fever fatigue syndrome (QFS). This guideline from the Netherlands helps doctors diagnose and treat QFS consistently. Many patients recover on their own within six months, but those who don't may benefit from cognitive behavioral therapy, a type of talk therapy that helps people manage chronic fatigue.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryCase-ControlEditor reviewed

Acute parvovirus B19 infection mimicking chronic fatigue syndrome.

Matano, Sadaya, Kinoshita, Hiroya, Tanigawa, Kiyoaki et al.·Internal medicine (Tokyo, Japan)·2003

This case study describes a woman in Japan who developed severe fatigue, pain, sleep problems, and other symptoms lasting two months that resembled ME/CFS. Blood tests showed she had a parvovirus B19 infection (a common virus), and she was also diagnosed with depression. Her symptoms improved after taking antidepressant medication and herbal treatments, even though the virus remained detectable in her blood for months. This case suggests that parvovirus B19 infection can sometimes produce symptoms similar to ME/CFS, especially in people who have experienced significant stress.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Post-viral fatigue syndrome. Epidemiology: lessons from the past.

Jenkins, R·British medical bulletin·1991

This review examines the history of post-viral fatigue syndrome (PVFS), including early outbreaks of what we now call ME/CFS, and how doctors have understood and tracked this illness over time. The author notes that cases are not officially recorded by health authorities, making it hard to spot when the condition becomes more common in communities. The review explores important questions about how the illness is defined, why some people develop it after infections, and how psychological factors relate to the physical symptoms.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryEditorialEditor reviewed

[Chronic fatigue syndrome].

Ewig, S, Dengler, H J·Klinische Wochenschrift·1990

This paper discusses chronic fatigue syndrome (CFS) as a condition that can develop after viral infections like Epstein-Barr virus or Coxsackie-B virus. Researchers noted that CFS may actually be several different diseases with different causes rather than one single condition. The authors emphasize that diagnosis requires ruling out other medical conditions first, and that at this time, we don't have enough knowledge to recommend specific treatments.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeEditor reviewed

The post-viral syndrome: a review.

Archer, M I·The Journal of the Royal College of General Practitioners·1987

This 1987 review examines post-viral syndrome (now often called ME/CFS), a condition that develops after viral infections. The author discusses whether the illness is caused by ongoing viral infection, psychological factors, or a combination of both. The review notes that different doctors diagnosed the condition at very different rates, and that many patients struggled to accept psychiatric support as part of their treatment.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

Current Concepts and Treatment Options in the Management of Fibromyalgia.

Li, Nathan, Cooper, Joshua, Fleming, Tanisha et al.·Psychopharmacology bulletin·2026

This article reviews what doctors and researchers currently understand about fibromyalgia, a chronic condition causing widespread pain and many other symptoms. While the exact causes remain unclear, scientists are finding potential clues in brain imaging, genes, and gut bacteria. The article explains how doctors diagnose fibromyalgia and what treatment options are available, emphasizing that managing it often requires a team approach with different specialists.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryCase-ControlEditor reviewed

Utility of Urinary β2-Microglobulin for Detection of Renal Sarcoidosis Without Pulmonary Involvement: A Case Report.

Oue, Yuri, Saiki, Ryosuke, Murata, Tomohiro et al.·Reports (MDPI)·2026

This case report describes a 60-year-old woman who was initially misdiagnosed with chronic fatigue syndrome when she actually had sarcoidosis (an inflammatory disease) affecting her kidneys. Doctors discovered this by finding very high levels of a protein called β2-microglobulin in her urine, which led to a kidney biopsy that confirmed the diagnosis. After treatment with a steroid medication, her kidney function improved and her fatigue completely resolved.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Reevaluating fibromyalgia diagnosis: a proposal to integrate deep tendon reflex responses into current criteria.

Coskun Benlidayi, Ilke, Ornek, Ceren, Deniz, Volkan et al.·Rheumatology international·2025

This review suggests that doctors could better diagnose fibromyalgia by adding a simple physical test—checking how strongly your reflexes react when tapped—to the current diagnostic methods. Right now, fibromyalgia is diagnosed mainly based on what patients report about their pain and symptoms, which can lead to missed or incorrect diagnoses. The researchers found that people with fibromyalgia often have stronger-than-normal reflex responses, which could help doctors rule out fibromyalgia or confirm it alongside other tests.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryCross-SectionalEditor reviewed

Diagnostic overshadowing in systemic lupus erythematosus (SLE): A qualitative study.

Harwood, Rupert, Wincup, Chris, D'Cruz, David et al.·Lupus·2025

This study looked at why people with lupus (SLE) often wait a long time to get diagnosed. Researchers found that doctors sometimes overlook or misinterpret lupus symptoms, attributing them instead to other causes like mental health problems, ME/CFS, or fibromyalgia. This "diagnostic overshadowing" can add years to someone's diagnostic journey and delay the treatment they need.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryCase-ControlEditor reviewed

Characterising DSCATT: A case series of Australian patients with debilitating symptom complexes attributed to ticks.

Schnall, Jesse, Oliver, Georgina, Braat, Sabine et al.·The Australian and New Zealand journal of psychiatry·2022

Researchers studied 29 Australian patients who believed their symptoms were caused by tick bites. Most had severe tiredness, headaches, and joint pain, and many had previously been diagnosed with conditions like ME/CFS or fibromyalgia. When doctors tested these patients, they found no evidence of Lyme disease or other common infections from ticks. The study suggests that tick-attributed illness in Australia remains unexplained and may overlap with other medically unexplained conditions.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Ehlers-Danlos Syndrome: Immunologic contrasts and connective tissue comparisons.

Islam, Mareesa, Chang, Christopher, Gershwin, M Eric·Journal of translational autoimmunity·2021

This review article explains Ehlers-Danlos Syndrome (EDS), a group of inherited disorders that affect connective tissue in the body, causing symptoms like loose, stretchy skin and flexible joints. The authors describe the 13 different types of EDS, how doctors diagnose them, and how they're treated. While some forms of EDS involve inflammation, the exact mechanisms causing the disease are not fully understood.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryEditor reviewed

How do women suffering from multiple chemical sensitivity experience the medical encounter? a qualitative study in Spain.

Briones-Vozmediano, Erica, Espinar-Ruiz, Eva·Disability and rehabilitation·2021

This study interviewed 22 Spanish women with Multiple Chemical Sensitivity (MCS) to understand their experiences with doctors and the healthcare system. The women reported two major problems: they cannot avoid exposure to chemicals in their environment, and they struggle to find effective treatment. Many also felt that healthcare providers didn't believe their illness was real or took their symptoms seriously.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Neurasthenia: Modern Malady or Historical Relic?

Overholser, James C, Beale, Eleanor E·The Journal of nervous and mental disease·2019

This article looks back at a condition called neurasthenia that doctors diagnosed frequently between 1869 and 1930, then largely abandoned. The authors found that many symptoms people with neurasthenia experienced—like exhaustion, mental fog, and physical weakness—are still seen today in conditions like chronic fatigue syndrome (ME/CFS) and fibromyalgia. By understanding neurasthenia's history, modern doctors may better recognize and treat these conditions and improve how they listen to their patients.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceMethods-PaperEditor reviewed

Development and Validation of a Serologic Test Panel for Detection of Powassan Virus Infection in U.S. Patients Residing in Regions Where Lyme Disease Is Endemic.

Thomm, Angela M, Schotthoefer, Anna M, Dupuis, Alan P et al.·mSphere·2018

This study developed and tested a new blood test to detect Powassan virus, a tick-borne infection that can cause serious neurological problems. The test uses two steps: first screening with one method, then confirming positive results with a more specific test. The researchers found the test was accurate and could identify Powassan infections in patients living in areas where Lyme disease is common, suggesting this virus may be more prevalent than previously recognized.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

Challenges in fibromyalgia diagnosis: from meaning of symptoms to fibromyalgia labeling.

Bidari, Ali, Ghavidel Parsa, Banafsheh, Ghalehbaghi, Babak·The Korean journal of pain·2018

Fibromyalgia (FM) is difficult to diagnose because there is no clear dividing line between having FM and not having it. This review examines why doctors and patients struggle with FM diagnosis, including how symptoms vary between people and over time, and how cultural and emotional factors influence whether a doctor labels someone as having FM. The authors argue that doctors' judgment based on talking with patients may be more reliable than relying only on scoring systems.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

Fibromyalgia: A Critical and Comprehensive Review.

Borchers, Andrea T, Gershwin, M Eric·Clinical reviews in allergy & immunology·2015

Fibromyalgia is a condition that causes widespread pain, fatigue, and sleep problems, and it shares many symptoms with other conditions that are hard to diagnose. This review explains that while some people think fibromyalgia might be caused by infection, inflammation, or injury, there is not strong evidence supporting these ideas. The authors recommend that treatment should focus on education, exercise, physical therapy, and approved medications rather than opioids.

Pain and SensitizationSleepDiagnostics
E3 PreliminaryPEM not requiredPreliminaryCase-ControlEditor reviewed

Epstein-barr virus infection masquerading as acute leukemia: a report of two cases and review of literature.

Chhabra, Puneet, Law, Arjun Dutt, Sharma, Upender et al.·Indian journal of hematology & blood transfusion : an official journal of Indian Society of Hematology and Blood Transfusion·2014

This study describes two cases where patients were initially thought to have acute leukemia based on blood tests, but they actually had Epstein-Barr virus (EBV) infections instead. One patient had infectious mononucleosis, and the other had a rare EBV-related immune condition. The study shows that EBV can sometimes look like leukemia under a microscope, which can lead to misdiagnosis.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceReview-NarrativeEditor reviewed

Chronic Lyme; diagnostic and therapeutic challenges.

Ljøstad, U, Mygland, Å·Acta neurologica Scandinavica. Supplementum·2013

This review discusses chronic Lyme disease, a rare condition caused by ongoing infection with the bacteria that causes Lyme disease. The main symptoms include progressive brain and spinal cord inflammation, skin changes, nerve damage, and joint pain. The authors explain how doctors can diagnose chronic Lyme using specific blood tests and cerebrospinal fluid tests, and recommend standard antibiotic treatment rather than experimental or prolonged approaches.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainEditorialEditor reviewed

Diagnosis and management of fibromyalgia: how and why.

Hayhoe, Simon·Pain management·2011

Fibromyalgia is a condition causing widespread muscle pain, tiredness, and sleep problems that doctors still debate about. It shares some features with ME/CFS and may involve both physical changes in how the nervous system processes pain and psychological factors. Treatment typically includes certain antidepressants, anti-seizure medications, and talking therapy with gentle exercise, though most patients only get partial improvement.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryEditor reviewed

Decades of delayed diagnosis in 4 levodopa-responsive young-onset monogenetic parkinsonism patients.

Ling, Helen, Braschinsky, Mark, Taba, Pille et al.·Movement disorders : official journal of the Movement Disorder Society·2011

This study describes four young patients who were initially misdiagnosed with psychological movement disorders or chronic fatigue syndrome, but actually had a genetic form of Parkinson's disease. Their misdiagnosis lasted 10 to 23 years before the correct diagnosis was made. Once they received the correct treatment with levodopa medication, they all improved significantly, showing that the right diagnosis and treatment can make a major difference.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

Fatigue and chronic fatigue in the elderly: definitions, diagnoses, and treatments.

Morelli, Vincent·Clinics in geriatric medicine·2011

This review article helps doctors understand fatigue in older adults by explaining three types: fatigue that comes on recently, fatigue that lasts a long time, and chronic fatigue syndrome. The article discusses how doctors can evaluate fatigue and offers both medication and non-medication treatments like exercise, vitamins, diet changes, and behavioral strategies.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryCase-ControlEditor reviewed

Sympathetic neural hyperalgesia edema syndrome, a frequent cause of pelvic pain in women, mistaken for Lyme disease with chronic fatigue.

Check, J H, Cohen, R·Clinical and experimental obstetrics & gynecology·2011

This study describes a woman who was diagnosed with Lyme disease and treated with antibiotics for chronic fatigue, but her symptoms didn't improve. Doctors then tested her ability to excrete water from her body and found it was impaired, suggesting a problem with her sympathetic nervous system (the part that controls automatic body functions). When she was treated with a stimulant medication instead, she improved significantly.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeEditor reviewed

[Contentious diseases--a medico-social phenomenon from an insurance medicine perspective].

Regenauer, A·Versicherungsmedizin·2008

This article examines a group of conditions—including ME/CFS, fibromyalgia, and others—that are difficult to diagnose with standard medical tests and have become controversial in healthcare and insurance systems. The author explores why these illnesses are questioned by insurers, what they have in common, and why cases are increasing in Western societies. The paper aims to help insurance companies better understand these conditions rather than dismiss them as imaginary.

Diagnostics
E3 PreliminaryPEM not requiredModerate confidenceMethods-PaperEditor reviewed

Brief and distinct empirical sleepiness and fatigue scales.

Bailes, Sally, Libman, Eva, Baltzan, Marc et al.·Journal of psychosomatic research·2006

Doctors and patients often use the words 'sleepiness' and 'fatigue' interchangeably, but they actually describe different experiences. This study created two short, separate questionnaires—one to measure sleepiness (the urge to sleep) and one to measure fatigue (overall exhaustion)—by pulling items from existing popular fatigue and sleepiness scales. Testing these new scales on people with ME/CFS, narcolepsy, and healthy controls showed they measure distinct conditions that may respond to different treatments.

SleepDiagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

[The problem of fatigue in neurological disorders].

Kumor, Klaudiusz, Pierzchała, Krystyna·Wiadomosci lekarskie (Warsaw, Poland : 1960)·2006

Fatigue is an extremely common and often severely disabling symptom in many neurological disorders, affecting 40–90% of patients with conditions like multiple sclerosis, Parkinson's disease, and stroke. This review explains that fatigue is a real medical symptom that should be carefully distinguished from depression, weakness, and sleepiness, though these conditions often occur together. Currently, doctors assess fatigue mainly through patient questionnaires, and there is no clear biological test or proven cure—treatments focus on addressing the underlying disease and using behavioral and psychological approaches.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryEditor reviewed

[Appraisal of Lyme borreliosis].

Hausotter, W·Versicherungsmedizin·2004

Lyme disease is an infection spread by tick bites that can cause many different symptoms affecting multiple body systems. This article discusses how doctors can better identify and diagnose Lyme disease, especially since its symptoms overlap with conditions like fibromyalgia and chronic fatigue syndrome. People who work outdoors in areas where Lyme disease is common face higher infection risks and may qualify for financial compensation if diagnosed.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainEditorialEditor reviewed

New insights into culture driven disorders.

Aceves-Avila, Francisco Javier, Ferrari, Robert, Ramos-Remus, Cesar·Best practice & research. Clinical rheumatology·2004

This editorial examines why conditions like ME/CFS, fibromyalgia, and similar illnesses are often difficult for doctors to diagnose using standard tests. The authors suggest that social and cultural factors—including how society views these diseases and how disability systems work—play a major role in how these illnesses show up in patients. They argue that understanding these broader influences could help doctors offer better support to patients.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

Myasthenia gravis: diagnostic mimics.

Engstrom, John W·Seminars in neurology·2004

This paper helps doctors tell the difference between myasthenia gravis (MG) and other conditions that look similar. MG causes muscle weakness that comes and goes, especially in the eyes and face. The authors review many other diseases—including neurological problems, infections, and other conditions—that can be mistaken for MG but are actually something else.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

The concepts of fatigue and depression in cancer.

Reuter, K, Härter, M·European journal of cancer care·2004

This paper examines why fatigue and depression often occur together in cancer patients and look so similar. The authors compare the symptoms of fatigue and depression to see what's the same and what's different, finding that while they share many symptoms, depression has specific psychological features that fatigue doesn't. They suggest that better tools are needed to help doctors tell the two conditions apart.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainEditorialEditor reviewed

Identification of masqueraders of autoimmune disease in the office.

Frieri, Marianne·Allergy and asthma proceedings·2003

This article discusses how several autoimmune and rheumatologic diseases can look like allergies or other conditions, making them easy to miss in a doctor's office. The author reviews nine conditions—including ME/CFS and fibromyalgia—that are often confused with other illnesses and explains how doctors can use blood tests and other tools to correctly identify them.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryReview-NarrativeEditor reviewed

Brainstem conundrum: the Chiari I malformation.

Mueller, D·Journal of the American Academy of Nurse Practitioners·2001

Chiari I Malformation is a condition where brain tissue extends into the spinal canal, causing various symptoms. This study reviews cases and explains why patients with this condition are often misdiagnosed with ME/CFS, fibromyalgia, or other illnesses, sometimes delaying proper diagnosis by months or years.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryCase-ControlEditor reviewed

Recognition of chronic carbon monoxide poisoning.

Knobeloch, L, Jackson, R·WMJ : official publication of the State Medical Society of Wisconsin·1999

This study describes three families in Wisconsin whose members were diagnosed with chronic fatigue syndrome, depression, and other illnesses that turned out to be caused by carbon monoxide leaks from faulty home heating systems. The families' symptoms—including fatigue, headaches, dizziness, and confusion—went undiagnosed until heating contractors found the problem. The authors remind doctors to consider carbon monoxide poisoning when patients have vague, ongoing symptoms, especially during winter.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainReview-NarrativeEditor reviewed

[Fibromyalgia. A critical review].

Cathébras, P, Lauwers, A, Rousset, H·Annales de medecine interne·1998

Fibromyalgia is a chronic pain condition that affects about 2% of the general population, with symptoms including widespread pain, fatigue, and sleep problems. This review examines how fibromyalgia overlaps with other conditions like ME/CFS and depression, and discusses why current treatments like antidepressants and therapy have limited effectiveness. The authors suggest that fibromyalgia may develop through interconnected factors rather than a single cause.

SleepDiagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeEditor reviewed

[Clinical aspects and neurologic expert assessment in sequelae of whiplash injury to the cervical spine].

Jenzer, G·Der Nervenarzt·1995

This review examined whiplash injuries to the neck and the long-term complications some patients develop, called chronic whiplash syndrome. The authors found that whiplash injuries can cause a complex mix of symptoms similar to those seen in chronic fatigue syndrome and fibromyalgia, making diagnosis challenging. Most people recover well from whiplash, though some experience prolonged difficulties.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceCross-SectionalEditor reviewed

Experience at a referral center for patients with suspected Lyme disease in an area of nonendemicity: first 65 patients.

Burdge, D R, O'Hanlon, D P·Clinical infectious diseases : an official publication of the Infectious Diseases Society of America·1993

Doctors at a hospital created a special clinic to evaluate patients who thought they had Lyme disease, even though Lyme disease is not common in that region. Out of 65 patients referred to the clinic, only 2 actually had Lyme disease. However, the clinic successfully identified other real medical conditions in most patients, including rheumatologic diseases, infections, and chronic fatigue syndrome.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryEditorialEditor reviewed

Neuro-ocular Lyme borreliosis.

Smith, J L·Neurologic clinics·1991

This study suggests that some patients diagnosed with chronic fatigue syndrome (CFS) might actually have Lyme disease, a tick-borne infection that can affect the brain and eyes. The authors recommend doctors ask CFS patients detailed questions about tick exposure and check for specific eye and neurological problems, then use blood and urine tests to look for evidence of Lyme infection.

Diagnostics
E3 PreliminaryPEM not requiredPreliminaryMethods-PaperEditor reviewed

A supplemental interview for forms of "affective spectrum disorder".

Pope, H G, Hudson, J I·International journal of psychiatry in medicine·1991

Researchers created a standardized interview tool to help diagnose seven different conditions—including chronic fatigue syndrome, fibromyalgia, irritable bowel syndrome, migraines, narcolepsy, Tourette's disorder, and kleptomania—based on the idea that these disorders may be related to each other. They developed questions following a recognized medical interview format and tested the tool with over 100 patients. The authors suggest these conditions may share common underlying features related to mood and emotion regulation.

Diagnostics
E3 PreliminaryPEM not requiredWeak / uncertainEditorialEditor reviewed

Is chronic fatigue syndrome synonymous with effort syndrome?

Rosen, S D, King, J C, Wilkinson, J B et al.·Journal of the Royal Society of Medicine·1990

This 1990 study examined whether chronic fatigue syndrome (CFS) might actually be caused by a breathing pattern problem called chronic hyperventilation. The researchers found that 93 out of 100 patients diagnosed with CFS showed signs of this breathing issue instead. They suggest doctors should check patients for hyperventilation problems before diagnosing them with ME or CFS.

Diagnostics
E0 ConsensusPEM requiredHigher confidenceGuidelineMachine-drafted

Appraisal of Clinical Practice Guideline: National Institute for Health and Care Excellence (NICE) clinical practice guideline for myalgic encephalomyelitis (or encephalopathy)/chronic fatigue syndrome: diagnosis and management.

F Tyson, Sarah·Journal of physiotherapy·2024

This paper reviews the 2021 NICE guidelines, which are official recommendations from the UK's National Institute for Health and Care Excellence on how to diagnose and treat ME/CFS. The review examines whether these guidelines are well-supported by evidence and practical for patients and healthcare providers to use. This is important because good clinical guidelines help ensure patients receive consistent, evidence-based care.

Diagnostics
E0 ConsensusPEM requiredHigher confidenceGuidelineMachine-drafted

NICE sets out steps NHS must take to implement ME/CFS guidelines.

Torjesen, Ingrid·BMJ (Clinical research ed.)·2022

In 2022, the UK's National Institute for Health and Care Excellence (NICE) released official guidelines for how the NHS should diagnose and treat ME/CFS. This article describes the key steps the NHS was told to take to implement these new guidelines. The guidelines aim to improve care and support for people living with ME/CFS across the country.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceGuidelineMachine-drafted

Approach to Fatigue: Best Practice.

Dukes, Jason C, Chakan, Matthew, Mills, Aaron et al.·The Medical clinics of North America·2021

Fatigue can come from many different causes, so doctors need to carefully listen to patients' histories and perform physical exams rather than just ordering lots of tests. Fatigue may be caused by an underlying medical condition that can be treated, or it may be a primary condition on its own (now called system exertion intolerance disease). Currently, there are no FDA-approved medications specifically for primary fatigue, so treatment focuses on personalized exercise programs and cognitive behavioral therapy.

Diagnostics
E0 ConsensusPEM requiredHigher confidenceGuidelineMachine-drafted

Diagnosis and management of chronic fatigue syndrome or myalgic encephalomyelitis (or encephalopathy): summary of NICE guidance.

Baker, R, Shaw, E J·BMJ (Clinical research ed.)·2007

This document summarizes official guidance from NICE (the UK's National Institute for Health and Care Excellence) on how to diagnose and manage ME/CFS. It provides recommendations for healthcare professionals on recognizing the condition, running appropriate tests, and treating patients with practical advice on activity management, rehabilitation, and when to refer patients to specialists.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceGuidelineMachine-drafted

NICE guidance on managing chronic fatigue syndrome/ME.

Hairon, Nerys, NICE·Nursing times·2007

This document provides official guidance from NICE (the UK's health authority) on how doctors should manage ME/CFS. It offers recommendations for diagnosing the condition, treating symptoms, and supporting patients in their daily lives. The guidance is based on the best evidence available and aims to help healthcare providers give consistent, appropriate care to people with ME/CFS.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceGuidelineMachine-drafted

Chronic fatigue syndrome. Clinical practice guidelines--2002.

Working Group of the Royal Australasian College of Physicians·The Medical journal of Australia·2002

These guidelines were created by Australian medical experts in 2002 to help doctors recognize, diagnose, and treat ME/CFS (a condition also called chronic fatigue syndrome). The guidelines set standards for how patients should be evaluated and managed, based on the best medical knowledge available at that time. They aim to improve the quality of care patients receive and reduce confusion about how to properly approach this illness.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceGuidelineMachine-drafted

Chronic fatigue syndrome: a step towards agreement.

Clark, Christopher, Buchwald, Dedra, MacIntyre, Anne et al.·Lancet (London, England)·2002

This 2002 guideline paper from leading ME/CFS researchers brought together different international perspectives on how to define and diagnose chronic fatigue syndrome, aiming to reduce confusion among doctors. The authors reviewed existing diagnostic criteria and clinical approaches to help create more consistent standards for identifying the condition. This work was an important step toward getting doctors and researchers to agree on what ME/CFS actually is.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceSystematic-ReviewMachine-drafted

Defining and managing chronic fatigue syndrome.

Mulrow, C D, Ramirez, G, Cornell, J E et al.·Evidence report/technology assessment (Summary)·2001

This 2001 review examined the medical literature on chronic fatigue syndrome to summarize what was known about how to define and manage the condition. The authors looked at existing research to identify consistent diagnostic criteria and treatment approaches. The goal was to create a clear picture of CFS based on the best available evidence at that time.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceReview-NarrativeMachine-drafted

Chronic fatigue syndrome in children and adolescents: a review.

Jordan, K M, Landis, D A, Downey, M C et al.·The Journal of adolescent health : official publication of the Society for Adolescent Medicine·1998

This review examined what was known about ME/CFS (chronic fatigue syndrome) specifically in children and teenagers. The authors looked at existing research to understand how the illness affects young people, how doctors recognize it, and what happens to patients over time. This study helps explain what ME/CFS looks like in younger patients, which is often different from how it appears in adults.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceReview-NarrativeMachine-drafted

The epidemiology of chronic fatigue syndrome.

Wessely, S·Epidemiologic reviews·1995

This review examined what we know about how common ME/CFS is, who develops it, and how it varies across different populations and regions. The researchers looked at existing research to understand the overall patterns of this illness in society. This helps doctors and patients understand whether ME/CFS is rare or relatively common, and whether certain groups are more likely to be affected.

Diagnostics
E0 ConsensusPEM unclearModerate confidenceGuidelineMachine-drafted

A report--chronic fatigue syndrome: guidelines for research.

Sharpe, M C, Archard, L C, Banatvala, J E et al.·Journal of the Royal Society of Medicine·1991

This 1991 document provides guidelines for how researchers should study ME/CFS to ensure consistent and reliable findings. Rather than reporting new experimental results, it offers recommendations on how to standardize research methods, study design, and patient definitions. It represents the thinking of leading medical experts who were trying to establish a common framework for ME/CFS research.

Diagnostics
E2 ModeratePEM unclearModerate confidenceCross-SectionalMachine-drafted

General practitioners' attitudes to patients with a self diagnosis of myalgic encephalomyelitis.

Scott, S, Deary, I, Pelosi, A J·BMJ (Clinical research ed.)·1995

This study looked at what general practitioners (GPs) think about patients who diagnose themselves with ME/CFS. Researchers surveyed GPs in Scotland to understand their attitudes toward self-diagnosed ME/CFS patients. The findings revealed important gaps between patient experiences and how some doctors view the condition.

Diagnostics
E2 ModeratePEM unclearPreliminaryObservationalMachine-drafted

[Epidemic myalgic encephalomyelitis].

Walther, H·Schweizerische Rundschau fur Medizin Praxis = Revue suisse de medecine Praxis·1972

This 1972 case study describes an outbreak of myalgic encephalomyelitis (ME), a serious illness causing muscle pain, brain inflammation, and extreme fatigue. The author documented patients who experienced this epidemic, helping early medical professionals recognize and understand the disease pattern.

Diagnostics
E2 ModeratePEM not requiredModerate confidenceCross-SectionalMachine-drafted

Comparison of Fatigue Severity and Quality of Life between Unexplained Fatigue Patients and Explained Fatigue Patients.

Yoo, Eun Hae, Choi, Eun Sil, Cho, Soo Hyun et al.·Korean journal of family medicine·2018

This study compared fatigue and quality of life in 200 Korean adults with fatigue. Researchers divided participants into two groups: those whose fatigue had a clear medical explanation (like anemia or thyroid disease) and those whose fatigue remained unexplained after testing. People with unexplained fatigue reported significantly lower quality of life, especially in physical functioning, compared to those with explained fatigue.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceCross-SectionalMachine-drafted

An Audit of UK Hospital Doctors' Knowledge and Experience of Myalgic Encephalomyelitis.

Hng, Keng Ngee, Geraghty, Keith, Pheby, Derek F H·Medicina (Kaunas, Lithuania)·2021

This study surveyed 44 UK hospital doctors about their knowledge of ME/CFS. Most doctors had little formal training on ME and lacked confidence in diagnosing or treating it, even though many had seen patients with the condition. The doctors showed significant gaps in understanding what ME actually is, how to properly diagnose it, and how to manage it effectively.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceReview-NarrativeMachine-drafted

["Tired, weak and exhausted" - which diagnostic steps make sense in the GP's practice?].

Schlüssel, Sabine, Gensichen, Jochen·MMW Fortschritte der Medizin·2020

This article reviews how general practitioners (GPs) can best diagnose ME/CFS by examining which tests and questions make the most sense in a regular doctor's office. The authors looked at practical diagnostic steps that doctors can use when patients report feeling tired, weak, and exhausted to help identify ME/CFS versus other conditions that cause similar symptoms.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeMachine-drafted

Differential diagnosis between "chronic fatigue" and "chronic fatigue syndrome".

Son, Chang-Gue·Integrative medicine research·2019

This article discusses the important difference between regular chronic fatigue (long-lasting tiredness) and Chronic Fatigue Syndrome (ME/CFS), a serious medical condition. The author explains why it's crucial to distinguish between these two conditions, since ME/CFS involves specific symptoms and has different causes than simple persistent tiredness.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryMachine-drafted

A woman in her 50s with chronic fatigue syndrome, sepsis and hyponatraemia.

Tazmini, Kiarash, Meling, Torstein R, Skattør, Thor Håkon et al.·Tidsskrift for den Norske laegeforening : tidsskrift for praktisk medicin, ny raekke·2017

This case report describes a woman in her 50s with ME/CFS who developed a serious blood infection (sepsis) and low sodium levels in her blood. The doctors documented her medical history and response to treatment. This single case highlights how ME/CFS patients can develop additional serious medical complications that require careful monitoring and treatment.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeMachine-drafted

Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness.

Military medicine·2015

This review article examines how ME/CFS is currently defined and proposes that our understanding of the illness needs to be updated. The authors, writing in a military medicine context, suggest that the condition extends beyond what the traditional name 'Myalgic Encephalomyelitis/Chronic Fatigue Syndrome' captures. The paper calls for a broader perspective on how this serious illness should be recognized and understood.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceMethods-PaperMachine-drafted

An overview of operationalizing criteria for ME, ME/CFS, and CFS case definitions.

Jason, Leonard A, So, Suzanna, Evans, Meredyth et al.·Journal of prevention & intervention in the community·2015

This study looks at how researchers define and identify ME/CFS using different sets of criteria. The researchers examined various diagnostic guidelines to understand how they work in practice and what makes a good case definition. This work helps ensure that when doctors diagnose ME/CFS, they're using clear, consistent standards.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeMachine-drafted

Medical constructions of long-term exhaustion, past and present.

Lian, Olaug S, Bondevik, Hilde·Sociology of health & illness·2015

This study looked at how doctors have understood exhaustion illnesses over time, comparing medical writings from 1860-1930 with those from 1970-2013. Researchers found that how these conditions were described and who had them changed dramatically: what was once seen as a physical disease affecting high-status men became viewed as a mental health problem affecting mostly women. The authors suggest these changes reflect cultural beliefs and values of each era, not just scientific discovery.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeMachine-drafted

[Distinguishing between depression and chronic fatigue syndrome].

Asberg, Marie, Nygren, Ake, Nager, Anna·Lakartidningen·2013

This study examines how depression and ME/CFS are different conditions, even though they can look similar on the surface. The researchers discuss why it's important for doctors to tell these conditions apart, since they require different treatment approaches. Understanding these differences helps ensure patients get the right care for their specific condition.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeMachine-drafted

[Changes on definition and diagnostic criteria of the chronic fatigue syndrome].

Qin, You, Pang, Feng-Shun, Cai, Bei-Yuan·Zhongguo Zhong xi yi jie he za zhi Zhongguo Zhongxiyi jiehe zazhi = Chinese journal of integrated traditional and Western medicine·2009

This article reviews how the definition and diagnostic criteria for ME/CFS have changed over time. The authors examine the evolution of how doctors identify and classify this condition using different diagnostic frameworks. Understanding these changes helps patients and doctors communicate more clearly about the disease.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeMachine-drafted

[The chronic fatigue syndrome and its diagnosis in internal medicine].

Barbado Hernández, F J, Gómez Cerezo, J, López Rodríguez, M et al.·Anales de medicina interna (Madrid, Spain : 1984)·2006

This article reviews how chronic fatigue syndrome (ME/CFS) is diagnosed and understood within internal medicine practice. The authors discuss the clinical features, diagnostic criteria, and challenges that doctors face when identifying ME/CFS in patients. The paper helps physicians recognize and properly diagnose this condition in their everyday practice.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeMachine-drafted

[Diagnosing asthenia and chronic fatigue syndrome].

Aslangul, Elisabeth, Le Jeunne, Claire·La Revue du praticien·2005

This article discusses how doctors can distinguish between general tiredness (asthenia) and ME/CFS, which is a serious long-term illness characterized by severe fatigue that doesn't improve with rest. The authors review the clinical features and diagnostic approaches that help healthcare providers identify ME/CFS in their patients. Understanding these differences is important so patients receive appropriate diagnosis and care.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeMachine-drafted

[Chronic fatigue syndrome: a syndrome in search of definition].

Sánchez Rodríguez, A, González Maroño, C, Sánchez Ledesma, M·Revista clinica espanola·2005

This review examines how ME/CFS is defined and understood in clinical practice. The authors discuss the challenges doctors face in recognizing and diagnosing this condition, since it affects different people in different ways. The study highlights why having clear, consistent definitions is essential for helping patients get proper care and advancing research.

Diagnostics
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Chronic fatigue syndrome. An overview of current concepts.

Aktan, Nadine M·Advance for nurse practitioners·2003

This is an overview article that explains what doctors and nurses understand about chronic fatigue syndrome (ME/CFS) based on current medical knowledge. The article reviews existing concepts and ideas about the condition rather than presenting new research data. It was written to help healthcare providers, particularly nurse practitioners, better understand and care for patients with ME/CFS.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeMachine-drafted

[Chronic fatigue syndrome--old wine in new bottles].

Leonhardt, T·Lakartidningen·2000

This 2000 article examines chronic fatigue syndrome (ME/CFS) and discusses how the condition may be understood through existing medical knowledge rather than as a completely new disease. The author explores what we already know about ME/CFS and how current medical frameworks apply to this complex illness.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeMachine-drafted

[Chronic fatigue syndrome--the disease and approaches to treatment].

Apel-Paz, M, Lior, B, Shemesh-Kigli, R·Harefuah·2000

This review article examines ME/CFS, describing what the disease is and discussing different treatment approaches. The authors provide an overview of the condition and explore various ways doctors have tried to help patients manage their symptoms. This type of review helps bring together existing knowledge about the illness and its management.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeMachine-drafted

[The chronic fatigue syndrome--a clinical entity or a complex of symptoms of various pathologic conditions].

Magdić, B, Ilić, T, Jovankić, O et al.·Vojnosanitetski pregled·1999

This paper examines whether ME/CFS is a single distinct disease or whether it might actually be a collection of different medical conditions that share similar symptoms. The authors review the clinical characteristics and evidence to help determine what ME/CFS really is from a medical standpoint.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeMachine-drafted

Misunderstood illnesses: fibromyalgia and chronic fatigue syndrome.

Robertson, T J·Alberta RN·1999

This article discusses how fibromyalgia and chronic fatigue syndrome (ME/CFS) are often misunderstood by healthcare providers and the public. The author explains the key characteristics of both conditions and why they are frequently confused with other illnesses or dismissed as not being 'real' diseases. The article aims to help people better understand these complex conditions.

Diagnostics
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Understanding chronic fatigue syndrome: an empirical guide to assessment and treatment.

Johnson, S K·Journal of health psychology·1999

This 1999 guide provides healthcare providers and patients with practical methods for evaluating and treating chronic fatigue syndrome (ME/CFS). The authors reviewed existing evidence to create a framework for assessment—including tests and questionnaires—and outlined treatment approaches. This work aims to help clinicians better recognize and manage ME/CFS in their patients.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeMachine-drafted

Report of a workshop on the epidemiology, natural history, and pathogenesis of chronic fatigue syndrome in adolescents.

Marshall, G S·The Journal of pediatrics·1999

This 1999 workshop report brought together experts to discuss what was known about ME/CFS in teenagers. The report summarized information about how common the illness is, how it develops over time, and what might cause it in young people. It served as an important step in recognizing that ME/CFS affects adolescents and that they needed specialized attention.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryMachine-drafted

A 56-year-old woman with chronic fatigue syndrome.

Komaroff, A L·JAMA·1997

This case study describes one patient's experience with ME/CFS, detailing her symptoms, medical history, and clinical presentation. The study provides an in-depth look at how ME/CFS affects a real person and what doctors observed during evaluation. This type of detailed patient story can help both patients and doctors better understand the condition.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryMachine-drafted

Meeting the frustrations of chronic fatigue syndrome.

Plioplys, A V, Plioplys, S, Davis, J S·Hospital practice (1995)·1997

This article discusses the challenges that ME/CFS patients face, including long-lasting disability and doctors who may not understand or believe in the condition. The authors explain that while there are no blood tests that definitively prove ME/CFS, doctors can confidently diagnose it using established criteria and ruling out other diseases. They suggest that medications can help manage symptoms while patients work toward recovery.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceGuidelineMachine-drafted

The chronic fatigue syndrome: a position paper.

Salit, I E·The Journal of rheumatology·1996

This is a position paper from a medical expert on chronic fatigue syndrome (ME/CFS) published in a rheumatology journal in 1996. Rather than presenting new research data, the author provides professional guidance and recommendations on how to understand and approach ME/CFS as a medical condition. This type of paper helps establish clinical standards and best practices for doctors treating patients with ME/CFS.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeMachine-drafted

10 key questions answered on chronic fatigue syndrome.

Gantz, N M·Contemporary internal medicine·1995

This is an editorial article that addresses 10 frequently asked questions about chronic fatigue syndrome (ME/CFS). Rather than reporting new research data, the author discusses common questions patients and doctors have about the condition, its diagnosis, and management. The article aims to help clarify misconceptions and provide practical information about ME/CFS.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeMachine-drafted

[Differential therapy of chronic fatigue syndrome].

Pankow, W, Feddersen, C O, von Wichert, P·Der Internist·1995

This 1995 study examines different treatment approaches for chronic fatigue syndrome. The authors review various therapeutic options that may help ME/CFS patients manage their symptoms. While specific details are limited due to the abstract not being available, this work represents an early clinical discussion of treatment strategies for this complex illness.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeMachine-drafted

Neurasthenia, myalgic encephalitis or cryptogenic chronic fatigue syndrome?

Leitch, A G·QJM : monthly journal of the Association of Physicians·1995

This 1995 paper explores the history and naming of ME/CFS, comparing three different terms used to describe the condition: neurasthenia (an older term), myalgic encephalitis, and chronic fatigue syndrome. The author examines how the same illness has been called different names over time and in different places, which can create confusion about what the condition actually is.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeMachine-drafted

A brief history of chronic fatigue syndrome.

Kim, E·JAMA·1994

This is a historical review article that traces how chronic fatigue syndrome (ME/CFS) has been understood and described over time. The article examines the evolution of the condition from early medical descriptions through the modern era, helping readers understand how our knowledge of ME/CFS has changed. It provides context for why ME/CFS was named and recognized as a legitimate medical condition.

Diagnostics
E3 PreliminaryPEM unclearModerate confidenceMethods-PaperMachine-drafted

From the Centers for Disease Control and Prevention. Inability of retroviral tests to identify persons with chronic fatigue syndrome, 1992.

JAMA·1993

In the early 1990s, researchers tested whether retroviruses (a type of virus) could be identified in people with ME/CFS using available blood tests. The CDC study found that these retroviral tests could not reliably identify or confirm ME/CFS in patients. This helped clarify that ME/CFS was not caused by the retroviruses being tested at that time.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryMachine-drafted

[A case from practice (279). 1. Chronic fatigue syndrome (CFS). 2. Psychosocial problems].

Kiener, S·Schweizerische Rundschau fur Medizin Praxis = Revue suisse de medecine Praxis·1993

This is a case report from a Swiss medical practice describing a patient with chronic fatigue syndrome (CFS) and the psychological and social problems that came along with the condition. The doctor documented how CFS affected this patient's daily life, relationships, and mental health. This type of case study helps doctors recognize CFS in their own patients and understand the broader impact it has beyond just physical symptoms.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeMachine-drafted

Chronic fatigue syndrome. A review from the general practice perspective.

Murdoch, J C·Australian family physician·1992

This 1992 review examines ME/CFS from the perspective of general practitioners (GPs) in Australia. The paper discusses how GPs can recognize, understand, and manage ME/CFS in their patients, highlighting the challenges of diagnosing a condition that doesn't show up on standard blood tests. It emphasizes that ME/CFS is a real medical condition deserving of proper clinical attention and patient support.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeMachine-drafted

[Chronic fatigue syndrome: the present concept and historical perspective].

Kitani, T·Nihon rinsho. Japanese journal of clinical medicine·1992

This is an editorial article that reviews what ME/CFS (chronic fatigue syndrome) is and how our understanding of it has changed over time. The author examines the current definition of ME/CFS and discusses its history, helping readers understand how medical perspectives on this illness have evolved.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryObservationalMachine-drafted

Clinical observations of chronic fatigue syndrome.

Mildon, C A·Canada diseases weekly report = Rapport hebdomadaire des maladies au Canada·1991

This 1991 study documents clinical observations of people with ME/CFS, describing what doctors noticed when examining patients with this condition. The report provides early descriptive information about how the illness presented in patients during that time period. While limited in scope, it contributes to the historical medical record of ME/CFS recognition.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeMachine-drafted

The chronic fatigue syndrome: a return to common sense.

Denman, A M·Postgraduate medical journal·1990

This 1990 opinion piece argues that ME/CFS should be understood through practical, straightforward clinical observation rather than overly complex theories. The author advocates for a 'common sense' approach to recognizing and managing the condition based on what doctors actually observe in patients.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeMachine-drafted

Myalgic encephalomyelitis.

Gordon, N·Developmental medicine and child neurology·1988

This is a review article about myalgic encephalomyelitis (ME), a serious condition that causes extreme tiredness, muscle pain, and cognitive difficulties. The author examines what was known about ME in 1988, including how it affects the brain and nervous system, and discusses different theories about what might cause it.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryMachine-drafted

Myalgic encephalomyelitis "an obscene cosmic joke"?

Church, A J·The Medical journal of Australia·1980

This 1980 case-control study examined patients with myalgic encephalomyelitis (ME/CFS) to better understand the condition. While the full details are limited, the study represents an early medical investigation into a disease that was not well understood at the time and was often dismissed by the medical community.

Diagnostics
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Benign myalgic encephalomyelitis: an outbreak in a nurses' school in Athens.

DAIKOS, G K, GARZONIS, S, PALEOLOGUE, A et al.·Lancet (London, England)·1959

This 1959 study documented an outbreak of ME/CFS-like illness among nursing students in Athens, Greece. Multiple students developed similar symptoms including muscle pain, fatigue, and neurological problems over a short period. The researchers observed the outbreak and recorded what happened, helping establish that ME/CFS can occur in groups of people.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryMachine-drafted

Benign myalgic encephalomyelitis.

BHATIA, B B, CHANDRA, S, BHUSHAN, C·Journal of the Indian Medical Association·1958

This is an early case-control study from 1958 examining what was then called benign myalgic encephalomyelitis. The researchers described and compared cases of the condition, though specific details about their findings are not available in the abstract. This represents one of the earliest formal medical investigations into what we now know as ME/CFS.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryMachine-drafted

Benign myalgic encephalomyelitis.

GALPINE, J F, BRADY, C·Lancet (London, England)·1957

This 1957 case-control study by Galpine and Brady documented cases of myalgic encephalomyelitis and compared them with control groups to understand the condition's features. The researchers aimed to establish that ME was a distinct medical condition with identifiable characteristics, rather than a purely psychological disorder. This early study helped establish the medical legitimacy of what patients and some doctors were observing as a real illness.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryObservationalMachine-drafted

EPIDEMIC myalgic encephalomyelitis.

British medical journal·1957

This 1957 study from the British Medical Journal documents cases of myalgic encephalomyelitis occurring in epidemic form—meaning multiple people in a community became ill at the same time. The researchers observed patients with this condition to better understand how it presented and spread.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryObservationalMachine-drafted

Benign myalgic encephalomyelitis (Akureyri disease, Iceland disease).

BLATTNER, R J·The Journal of pediatrics·1956

This 1956 study describes an outbreak of a disease called Akureyri disease (also known as Iceland disease) that affected multiple people in Iceland. The disease caused muscle pain and fatigue similar to what we now call ME/CFS. This early medical observation helped document that ME/CFS-like illnesses have occurred in clusters and have affected communities for decades.

Diagnostics
E3 PreliminaryPEM unclearWeak / uncertainReview-NarrativeMachine-drafted

Can fibromyalgia and chronic fatigue syndrome be cured by surgery?

Wilke, W S·Cleveland Clinic journal of medicine·2001

This review article examines whether surgery can cure fibromyalgia and chronic fatigue syndrome (ME/CFS). The author concludes that surgery is not an effective treatment for these conditions. This is important because some patients and providers have explored surgical approaches, but the evidence does not support this as a cure.

Diagnostics
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[Similarities of chronic fatigue syndrome, fibromyalgia and multiple chemical sensitivity].

Csef, H·Deutsche medizinische Wochenschrift (1946)·1999

This study looked at three conditions—chronic fatigue syndrome (ME/CFS), fibromyalgia, and multiple chemical sensitivity—to see if they share similarities. The researchers examined how these conditions might be related to each other based on their common features. Understanding these connections could help doctors better recognize and treat patients who experience overlapping symptoms across these conditions.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryReview-NarrativeMachine-drafted

[Chronic fatigue syndrome, fibromyalgia and depression].

Martin-Du-Pan, R·Revue medicale de la Suisse romande·1990

This 1990 review article examines the relationships between chronic fatigue syndrome (ME/CFS), fibromyalgia, and depression. The author discusses how these three conditions sometimes occur together and explores whether they share common features or causes. The paper helps clarify how ME/CFS and fibromyalgia are distinct from depression, even though all three can cause fatigue and other overlapping symptoms.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryMachine-drafted

[A case from practice (343). Chronic fatigue syndrome following Lyme borreliosis].

Diamantis, I·Praxis·1996

This case study describes a patient who developed chronic fatigue syndrome (ME/CFS) following a Lyme borreliosis infection (transmitted by tick bite). The report documents one person's experience, showing how a tick-borne infection may have triggered or contributed to the development of ME/CFS symptoms.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryMachine-drafted

Chronic fatigue syndrome: chronic ciguatera poisoning as a differential diagnosis.

Pearn, J H·The Medical journal of Australia·1997

This study examines whether some people diagnosed with ME/CFS might actually have chronic ciguatera poisoning, a illness caused by eating contaminated seafood. The researchers suggest that certain ME/CFS cases could be misdiagnosed cases of ciguatera, which can cause similar long-lasting fatigue and other symptoms. The study calls for doctors to consider this possibility when evaluating patients with ME/CFS symptoms.

Diagnostics
E3 PreliminaryPEM unclearPreliminaryCase-ControlMachine-drafted

Chronic fatigue syndrome or affective disorder? Implications of the diagnosis on management.

Giannopoulou, Joanna, Marriott, Sarah·European child & adolescent psychiatry·1994

This case study describes a teenage boy who was initially thought to have post-viral fatigue syndrome (a condition similar to ME/CFS that follows infections) but was actually diagnosed with bipolar disorder, a mental health condition involving extreme mood swings. The doctors discuss how difficult it can be to tell the difference between these two conditions in young people, and how getting the diagnosis wrong can seriously affect their treatment and development.

Diagnostics

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