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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 6,167 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

221–240 of 517 studies

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateBehavioralPEM unclearCross-Sectional

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 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateDiagnosticPEM not requiredMethods-Paper

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.

E2 ModerateBehavioralPEM unclearCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM unclearCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM not requiredCross-Sectional

[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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM not requiredCase-Control

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.

E2 ModerateCohortPEM not requiredObservational

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateBehavioralPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM unclearObservational

'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.

E2 ModerateCohortPEM not requiredCross-Sectional

'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.

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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.