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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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© 2026 ME/CFS Atlas

ME/CFS Evidence Browser — Classified Studies on Myalgic Encephalomyelitis

Evidence browser

Search and filter 6,167 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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517 studies

E0 — Consensus643E1 — Replicated320E2 — Moderate2,782E3 — Preliminary2,422

ME/CFS4,025Long COVID217Post-infectious189Overlapping1,050

Required for diagnosis414Not specified / unclear2,219Not required3,534

Post-Exertional Malaise1,064Cognitive Dysfunction1,735Pain1,620Unrefreshing Sleep799Orthostatic Intolerance478

Cytokines818Gene Expression567Metabolomics473Neuroimaging468Autoantibodies458

Infection-Triggered1,174Long COVID Overlap588Pediatric493Severe231

Strong Phenotyping438Sex-Stratified326Severe ME Included118

Systematic Review265Meta-Analysis60RCT300

Peer-reviewed6,110Preprint3Unclear54

261–280 of 517 studies

E2 ModerateCohortPEM not requiredObservational

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.

E2 ModerateBehavioralPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM unclearCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateBehavioralPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM unclearObservational

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.

E2 ModerateBehavioralPEM not requiredObservational

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.

E2 ModerateCohortPEM unclearObservational

[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.

E3 PreliminaryReviewPEM not requiredReview-Narrative

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.

E3 PreliminaryCohortPEM not requiredCase-Control

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.

E3 PreliminaryCohortPEM unclearCross-Sectional

["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.

E3 PreliminaryDiagnosticPEM unclearMethods-Paper

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.

E3 PreliminaryDiagnosticPEM not required

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.

E3 PreliminaryReviewPEM unclearReview-Narrative

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.

E3 PreliminaryCohortPEM unclearCross-Sectional

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.

E3 PreliminaryDiagnosticPEM unclearMethods-Paper

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.

E3 PreliminaryReviewPEM unclearReview-Narrative

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 PreliminaryDiagnosticPEM not required

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.

E3 PreliminaryCommentaryPEM not requiredEditorial

[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.

E3 PreliminaryDiagnosticPEM unclearMethods-Paper

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.

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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.