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ME/CFS Atlas — A public knowledge atlas for ME/CFS

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ME/CFS Atlas is an evidence reference platform, not a medical provider. Content is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.

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ME/CFS Evidence Browser — Classified Studies on Myalgic Encephalomyelitis

Evidence browser

Search and filter 6,145 studies by evidence level, diagnostic criteria, PEM status, and research domain. Each entry links to the original source.

Studies sorted by evidence level, then year. Browse by topic instead →

Evidence level (E0–E3) reflects study type and replication, not methodological quality. A weak systematic review still sits at E0. How evidence levels work →

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510 studies

E0 — Consensus637E1 — Replicated320E2 — Moderate2,768E3 — Preliminary2,420

ME/CFS4,014Long COVID212Post-infectious189Overlapping1,045

Required for diagnosis412Not specified / unclear2,201Not required3,532

Post-Exertional Malaise1,055Cognitive Dysfunction1,723Pain1,612Unrefreshing Sleep793Orthostatic Intolerance474

Cytokines816Gene Expression567Metabolomics469Neuroimaging466Autoantibodies457

Infection-Triggered1,170Long COVID Overlap580Pediatric492Severe228

Strong Phenotyping435Sex-Stratified326Severe ME Included116

Systematic Review263Meta-Analysis60RCT300

Peer-reviewed6,088Preprint3Unclear54

161–180 of 510 studies

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM unclearCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModeratePEM not requiredRegistry-Resource

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateBehavioralPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM unclearCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateBehavioralPEM not requiredCross-Sectional

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 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM unclearCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateBehavioralPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM unclearCross-Sectional

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.

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PEM Immune Neuro Metabolic Biomarkers Severe ME Long COVID Cognitive

Curated Collections

Thematic groupings by clinical question or research area.

Neuroinflammation Evidence

PET imaging and other studies providing evidence for brain inflammation in ME/CFS.

Metabolism & Mitochondria

Metabolomics and mitochondrial function studies revealing energy metabolism disruption.

Biomarkers

Studies identifying potential biological markers for ME/CFS diagnosis and stratification.

PEM-Specific Research

Studies specifically examining post-exertional malaise, the hallmark symptom of ME/CFS.