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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

221–240 of 510 studies

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

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

[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

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

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

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 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 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 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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateCohortPEM unclearCross-Sectional

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.

E2 ModerateCohortPEM not requiredObservational

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.

E2 ModerateCohortPEM not requiredObservational

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.

E2 ModerateCohortPEM not requiredCross-Sectional

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.

E2 ModerateBehavioralPEM unclearObservational

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.

E2 ModerateCohortPEM unclearCross-Sectional

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.

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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.