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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

381–400 of 510 studies

E3 PreliminaryDiagnosticPEM unclearCross-Sectional

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.

E3 PreliminaryDiagnosticPEM not requiredMethods-Paper

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.

E3 PreliminaryDiagnosticPEM not requiredMethods-Paper

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.

E3 PreliminaryReviewPEM unclearReview-Narrative

[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.

E3 PreliminaryReviewPEM not requiredReview-Narrative

[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.

E3 PreliminaryCohortPEM unclearCross-Sectional

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.

E3 PreliminaryReviewPEM unclearReview-Narrative

[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.

E3 PreliminaryCommentaryPEM not requiredEditorial

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.

E3 PreliminaryReviewPEM unclearReview-Narrative

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.

E3 PreliminaryReviewPEM not requiredReview-Narrative

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.

E3 PreliminaryReviewPEM unclearReview-Narrative

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.

E3 PreliminaryReviewPEM unclearReview-Narrative

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.

E3 PreliminaryPEM not required

[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.

E3 PreliminaryReviewPEM not requiredReview-Narrative

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.

E3 PreliminaryCommentaryPEM not requiredEditorial

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.

E3 PreliminaryGuidelinePEM not requiredEditorial

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.

E3 PreliminaryBehavioralPEM not requiredCase-Control

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.

E3 PreliminaryReviewPEM unclearReview-Narrative

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.

E3 PreliminaryReviewPEM unclearReview-Narrative

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.

E3 PreliminaryDiagnosticPEM not requiredMethods-Paper

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.

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Or browse by topic

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.