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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

241–260 of 510 studies

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 ModerateCohortPEM not requiredCross-Sectional

Prevalence of chronic fatigue syndrome in Italian patients with persistent fatigue.

Conti, F, Priori, R, De Petrillo, G et al.·Annali italiani di medicina interna : organo ufficiale della Societa italiana di medicina interna·1994

Researchers in Rome studied 63 patients with persistent fatigue lasting at least 6 months to see how many actually had ME/CFS. They found that only 6 patients (about 10%) met the official diagnostic criteria for ME/CFS, while 37 patients (59%) had other medical conditions explaining their fatigue, such as infections or other illnesses. This suggests that ME/CFS is relatively uncommon as a cause of severe fatigue compared to other treatable conditions.

E2 ModerateBehavioralPEM not requiredCross-Sectional

[Epidemiologic study of chronic fatigue in primary care (general practice)].

Mann, A H, Mc Donald, E, Cope, H et al.·L'Encephale·1994

Researchers studied fatigue in patients visiting regular doctors' offices to understand how common it is and what causes it. They found that some patients had long-lasting, disabling fatigue, but these patients were very different from each other in why they thought they were tired. Most of these patients also had depression or other mental health conditions alongside their fatigue.

E2 ModerateCohortPEM unclearCross-Sectional

Comparison of patients with chronic fatigue syndrome, fibromyalgia, and multiple chemical sensitivities.

Buchwald, D, Garrity, D·Archives of internal medicine·1994

This study compared 90 patients with three conditions that cause fatigue and other symptoms: ME/CFS, fibromyalgia, and multiple chemical sensitivities. The researchers found that these three conditions are very similar in many ways—patients often report overlapping symptoms, and many people meet the criteria for more than one condition. All three groups used a lot of healthcare services, visiting doctors about 22-40 times per year on average.

E2 ModerateCohortPEM not requiredCross-Sectional

A comparison of case definitions of chronic fatigue syndrome.

Bates, D W, Buchwald, D, Lee, J et al.·Clinical infectious diseases : an official publication of the Infectious Diseases Society of America·1994

This study tested whether three different sets of diagnostic criteria for ME/CFS identified the same patients. Researchers looked at 805 patients at two clinics and found that about 55-61% met each of the three definitions, though different patients sometimes qualified under different criteria. The study suggests that using broader, more flexible definitions might better capture people with ME/CFS.

E2 ModerateCohortPEM not requiredCross-Sectional

Prevalence of chronic fatigue syndrome-related symptoms among nurses.

Jason, L A, Taylor, S L, Johnson, S et al.·Evaluation & the health professions·1993

This study looked at how common ME/CFS-related symptoms are among nurses. Researchers surveyed a group of nurses and found that when using different definitions of the illness, more nurses showed signs of ME/CFS than had been found in previous studies of the general population. This was the first study to specifically examine ME/CFS in healthcare workers.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Chronic fatigue and chronic fatigue syndrome: clinical epidemiology and aetiological classification.

Manu, P, Lane, T J, Matthews, D A·Ciba Foundation symposium·1993

This study looked at 405 patients who came to a hospital complaining of chronic fatigue and tried to figure out what was causing it. Doctors found that most patients had psychiatric conditions like depression or anxiety rather than physical diseases. About 30% of patients met the definition for ME/CFS, and these patients were more likely to attribute their illness to a viral infection than other fatigued patients.

E2 ModerateCohortPEM unclearCross-Sectional

The overdiagnosis of Lyme disease.

Steere, A C, Taylor, E, McHugh, G L et al.·JAMA·1993

This study looked at 788 people referred to a Lyme disease clinic who were thought to have Lyme disease. Researchers found that only 23% actually had active Lyme disease, while 57% did not have Lyme disease at all—many of these patients had chronic fatigue syndrome or fibromyalgia instead. The main problem was that patients were being incorrectly diagnosed with Lyme disease and given antibiotics that didn't help because they didn't actually have the infection.

E2 ModerateCohortPEM not requiredObservational

Epidemiology of chronic fatigue syndrome: the Centers for Disease Control Study.

Gunn, W J, Connell, D B, Randall, B·Ciba Foundation symposium·1993

Between 1989 and 1991, the CDC tracked patients with chronic fatigue syndrome across four U.S. cities to understand how common the illness is and who gets it. Researchers found that only about 1 in 4 patients referred to them actually met the strict diagnostic criteria for CFS, while others had different medical conditions or psychiatric histories that might explain their fatigue. The study estimated that CFS affects roughly 2–11 people per 100,000 in the general population, and it most commonly affected women in their 30s.

E2 ModerateCohortPEM not requiredCase-Control

A controlled study of brain magnetic resonance imaging in patients with the chronic fatigue syndrome.

Natelson, B H, Cohen, J M, Brassloff, I et al.·Journal of the neurological sciences·1993

Researchers compared brain scans (MRIs) of 52 people with ME/CFS to 52 similar healthy people. They found that ME/CFS patients were much more likely to have abnormal brain scans—27% compared to only 2% in the control group. The abnormalities included areas of white matter changes and some brain tissue enlargement, though the researchers noted that some of these findings might actually indicate other medical conditions rather than ME/CFS itself.

E2 ModerateCohortPEM not requiredCross-Sectional

Prevalence of fatigue and chronic fatigue syndrome in a primary care practice.

Bates, D W, Schmitt, W, Buchwald, D et al.·Archives of internal medicine·1993

This study looked at how common severe, long-lasting fatigue is in a primary care doctor's office and how often it is ME/CFS. Researchers found that while about 27% of patients had long-term fatigue affecting their daily life, most could be explained by other medical or mental health conditions. Only about 0.3% to 1% of patients actually had ME/CFS, depending on which diagnostic criteria were used.

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

Chronic fatigue syndrome criteria. A critique of the requirement for multiple physical complaints.

Katon, W, Russo, J·Archives of internal medicine·1992

This study looked at 285 people with chronic fatigue to understand whether having many physical symptoms was linked to psychiatric conditions like depression and anxiety. Researchers found that patients reporting more unexplained physical symptoms were significantly more likely to have current or past psychiatric diagnoses. The authors suggest that ME/CFS diagnostic criteria should be changed to include people with fatigue and few physical symptoms, and potentially exclude those with many physical complaints.

E2 ModerateCohortPEM not requiredCross-Sectional

Estimating the prevalence of chronic fatigue syndrome and associated symptoms in the community.

Price, R K, North, C S, Wessely, S et al.·Public health reports (Washington, D.C. : 1974)·1992

This study looked at how common chronic fatigue syndrome (CFS) is in the general population by surveying over 13,500 people between 1981 and 1984. Researchers found that while about 23% of people reported experiencing persistent fatigue at some point in their lives, actual CFS meeting strict diagnostic criteria was extremely rare—only 1 person in the entire study group had the condition. When researchers excluded people with other medical or psychiatric illnesses, CFS became even rarer.

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 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 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.

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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.