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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 6,166 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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516 studies

E0 — Consensus643E1 — Replicated320E2 — Moderate2,781E3 — Preliminary2,422

ME/CFS4,025Long COVID216Post-infectious189Overlapping1,050

Required for diagnosis414Not specified / unclear2,218Not required3,534

Post-Exertional Malaise1,063Cognitive Dysfunction1,735Pain1,620Unrefreshing Sleep799Orthostatic Intolerance478

Cytokines818Gene Expression567Metabolomics473Neuroimaging468Autoantibodies458

Infection-Triggered1,174Long COVID Overlap587Pediatric493Severe231

Strong Phenotyping438Sex-Stratified326Severe ME Included118

Systematic Review265Meta-Analysis60RCT300

Peer-reviewed6,109Preprint3Unclear54

181–200 of 516 studies

E2 ModerateCohortPEM not requiredCross-Sectional

Comparative epidemiology of chronic fatigue syndrome in Brazilian and British primary care: prevalence and recognition.

Cho, Hyong Jin, Menezes, Paulo Rossi, Hotopf, Matthew et al.·The British journal of psychiatry : the journal of mental science·2009

This study looked at how often ME/CFS occurs in two very different cities—London and São Paulo, Brazil—and whether doctors recognize it as a real condition. Researchers surveyed over 6,000 primary care patients and found that ME/CFS affected roughly the same number of people in both places (about 2%). However, while British doctors had diagnosed some cases, Brazilian doctors had not diagnosed any, suggesting that cultural and healthcare system differences affect how the disease is recognized rather than how common it actually is.

E2 ModerateCohortPEM unclearCross-Sectional

Implications of gender in chronic Lyme disease.

Wormser, Gary P, Shapiro, Eugene D·Journal of women's health (2002)·2009

This study compared three groups of patients: those with confirmed Lyme disease, those with lingering symptoms after Lyme disease treatment (post-Lyme disease syndrome), and those diagnosed with 'chronic Lyme disease' (a less clearly defined condition). The researchers found that women made up a much larger percentage of the chronic Lyme disease group compared to the other two groups. This suggests that some patients labeled with chronic Lyme disease may actually have other conditions like fibromyalgia or chronic fatigue syndrome that also affect more women.

E2 ModerateCohortPEM not requiredCross-Sectional

Demographic and clinical aspects of an Italian patient population with chronic fatigue syndrome.

Carlo-Stella, N, Cuccia, M·Reumatismo·2009

This Italian study surveyed patients diagnosed with ME/CFS to understand their symptoms and backgrounds. The researchers found that Italian patients with ME/CFS experience persistent fatigue along with symptoms that resemble infectious illnesses, neurological problems, and joint/muscle issues—similar to what has been reported in other countries.

E2 ModerateCohortPEM not requiredCross-Sectional

An evaluation of exclusionary medical/psychiatric conditions in the definition of chronic fatigue syndrome.

Jones, James F, Lin, Jin-Mann S, Maloney, Elizabeth M et al.·BMC medicine·2009

This study looked at whether people diagnosed with ME/CFS who also have other medical or psychiatric conditions (like depression or thyroid disease) are actually sicker than those with ME/CFS alone. Researchers surveyed over 5,600 people in Georgia and clinically evaluated 781 of them. They found that about one-third of people had additional conditions, but surprisingly, people with and without these extra conditions reported similar levels of fatigue and disability.

E2 ModerateCohortPEM not requiredCross-Sectional

Are chronic fatigue and chronic fatigue syndrome valid clinical entities across countries and health-care settings?

Hickie, Ian, Davenport, Tracey, Vernon, Suzanne D et al.·The Australian and New Zealand journal of psychiatry·2009

This large international study analyzed data from nearly 38,000 people across 21 countries to determine whether chronic fatigue and ME/CFS are real, recognizable conditions. Researchers found that people with these conditions share a consistent pattern of five main symptom types—muscle pain and fatigue, thinking difficulties, inflammation-related symptoms, sleep problems, and mood changes—regardless of where they live or which type of doctor they see. This consistency across different countries and healthcare settings provides strong evidence that chronic fatigue and ME/CFS are genuine medical conditions, not just psychiatric problems.

E2 ModerateCohortPEM unclearObservational

Chronic fatigue syndrome and related disorders in UK veterans of the Gulf War 1990-1991: results from a two-phase cohort study.

Ismail, K, Kent, K, Sherwood, R et al.·Psychological medicine·2008

This study looked at whether Gulf War veterans had higher rates of ME/CFS and related conditions compared to other military personnel. Researchers surveyed over 10,000 military personnel and then closely examined disabled Gulf War veterans and similarly disabled veterans who served elsewhere. They found that Gulf War veterans were about 8 times more likely to meet the criteria for ME/CFS than veterans who were not deployed to the Gulf.

E2 ModerateCohortPEM unclearCross-Sectional

The awareness of chronic fatigue syndrome: a comparative study in Brazil and the United Kingdom.

Cho, Hyong Jin, Menezes, Paulo Rossi, Bhugra, Dinesh et al.·Journal of psychosomatic research·2008

This study compared how well doctors and the general public in Brazil and the United Kingdom recognize ME/CFS. Researchers found that far fewer people in Brazil were familiar with the condition compared to the UK—only 16% of Brazilian patients had heard of it, compared to 55% in Britain. Even among Brazilian specialist doctors, less than a third could identify ME/CFS from a typical case description.

E2 ModerateCohortPEM unclearCross-Sectional

Negotiating the diagnostic uncertainty of contested illnesses: physician practices and paradigms.

Swoboda, Debra A·Health (London, England : 1997)·2008

This study surveyed 800 U.S. doctors to understand how they diagnose ME/CFS and similar illnesses that lack clear lab tests or agreed-upon causes. Researchers found that many doctors do diagnose these conditions, even without complete scientific consensus, by using practical strategies like consulting expert resources, ordering specific tests, and considering how the body might be affected. The study shows that doctors can rationally diagnose ME/CFS by using thoughtful decision-making processes, and that patients may benefit from seeing doctors who use these careful diagnostic approaches.

E2 ModerateCohortPEM not requiredCross-Sectional

The management of children with chronic fatigue syndrome-like illness in primary care: a cross-sectional study.

Saidi, Guitta, Haines, Linda·The British journal of general practice : the journal of the Royal College of General Practitioners·2006

This study looked at how family doctors (GPs) in the UK identify and care for children and teenagers with ME/CFS-like illness in their regular clinics. Researchers reviewed medical records and patient experiences from 116 young people with severe fatigue lasting over 3 months. Most were girls around age 13, and their illness had lasted several years. The study found that GPs diagnosed about half of them with CFS/ME, often within 6 months, and referred most patients to specialists or suggested strategies like pacing and graded exercise.

E2 ModerateCohortPEM not requiredLongitudinal

Post-infective and chronic fatigue syndromes precipitated by viral and non-viral pathogens: prospective cohort study.

Hickie, Ian, Davenport, Tracey, Wakefield, Denis et al.·BMJ (Clinical research ed.)·2006

This study followed 253 people in Australia who had three different infections (glandular fever, Q fever, and a virus causing joint pain) to see how many developed long-lasting fatigue and related symptoms. About 11% of people met the diagnostic criteria for chronic fatigue syndrome six months after infection, experiencing disabling fatigue, pain, thinking difficulties, and mood changes. The researchers found that the severity of the initial infection—not personality type, prior health, or the specific germ involved—was the main predictor of who would develop prolonged illness.

E2 ModerateCohortPEM unclearCross-Sectional

Prevalence of chronic fatigue and chronic fatigue syndrome in Korea: community-based primary care study.

Kim, Cheol Hwan, Shin, Ho Cheol, Won, Chang Won·Journal of Korean medical science·2005

Researchers in Korea asked nearly 1,650 patients visiting primary care clinics about fatigue and checked whether they had chronic fatigue or ME/CFS. They found that about 8% of patients had chronic fatigue, but only 0.6% (less than 1%) had ME/CFS. Most chronic fatigue cases could be explained by physical or psychological causes, while ME/CFS cases had no clear medical explanation.

E2 ModerateCohortPEM not requiredCross-Sectional

The prevalence of self-reported chronic fatigue in a U.S. twin registry.

Furberg, Helena, Olarte, Megan, Afari, Niloo et al.·Journal of psychosomatic research·2005

This study looked at how common fatigue-related illnesses are among twins in the United States and found that fatigue symptoms are quite common, affecting over one-third of people at some point in their lives. Women were 2-3 times more likely to report fatigue than men, and women typically experienced it at younger ages. People with chronic fatigue had significantly worse quality of life and more additional symptoms than those without fatigue.

E2 ModerateCohortPEM not requiredCross-Sectional

The definition of disabling fatigue in children and adolescents.

Fowler, Tom, Duthie, Pamela, Thapar, Anita et al.·BMC family practice·2005

This study looked at how disabling fatigue in children and teens should be defined, since the current definition used for adults might not fit young people well. Researchers found that children with disabling fatigue that didn't quite meet the strict adult criteria still suffered just as much and missed just as much school as those who did meet the strict criteria. The study suggests that doctors should use a broader, less restrictive definition to catch all children who need help.

E2 ModerateCohortPEM not requiredCross-Sectional

Chronic Fatigue Syndrome: a survey of GPs' attitudes and knowledge.

Bowen, Jo, Pheby, Derek, Charlett, Andre et al.·Family practice·2005

This study asked general practitioners (GPs) in the UK what they knew about ME/CFS and how confident they felt diagnosing and treating it. About half of the GPs surveyed didn't feel confident making a diagnosis, and 41% didn't feel confident treating the condition. The study found that GPs who believed ME/CFS was a real medical condition had much more positive attitudes toward patients.

E2 ModerateCohortPEM unclearCase-Control

Chronic fatigue syndrome--a clinically empirical approach to its definition and study.

Reeves, William C, Wagner, Dieter, Nisenbaum, Rosane et al.·BMC medicine·2005

This study tested two different ways of diagnosing ME/CFS to see which one worked better. Researchers in Kansas recruited 227 people—some with ME/CFS, some with unexplained fatigue that didn't meet ME/CFS criteria, some depressed, and some healthy—and admitted them to a hospital for two days of testing. They found that a new method for diagnosing ME/CFS (based on measuring fatigue severity, disability, and symptoms) worked much better at identifying truly ill people than the old method.

E2 ModerateCohortPEM not requiredCross-Sectional

Primary healthcare provision and Chronic Fatigue Syndrome: a survey of patients' and General Practitioners' beliefs.

Thomas, Marie A, Smith, Andrew P·BMC family practice·2005

This study asked both ME/CFS patients and general practitioners (GPs) in Wales what they knew about ME/CFS. Researchers found that many GPs had very little specialist knowledge about the condition, and concerningly, only about half of the GPs surveyed actually believed ME/CFS was a real illness. The study suggested that creating better educational materials for both GPs and patients could help improve understanding and care.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Chronic fatigue syndrome of childhood. Comparative study with emotional disorders.

Garralda, M Elena, Rangel, Luiza·European child & adolescent psychiatry·2005

This study compared children diagnosed with ME/CFS to children with emotional disorders like anxiety and depression to see how these conditions differ. While both groups of children experienced some similar emotional challenges, children with ME/CFS reported more severe tiredness and physical symptoms, and were more likely to have had infections or medical problems before getting sick. The results show that ME/CFS and emotional disorders can look similar in some ways but have important differences.

E2 ModerateCohortPEM not requiredCross-Sectional

Chronic fatigue in a population sample: definitions and heterogeneity.

Sullivan, Patrick F, Pedersen, Nancy L, Jacks, Andreas et al.·Psychological medicine·2005

This study looked at how doctors define ME/CFS by surveying over 31,000 Swedish adults about their fatigue symptoms. The researchers found that the current official checklist for diagnosing ME/CFS (requiring 4 out of 8 specific symptoms) doesn't match how fatigue actually varies in real populations. Using statistical analysis, they identified a recognizable ME/CFS-like illness pattern, but concluded that a simpler definition focusing on severe, disabling fatigue might work better.

E2 ModerateCohortPEM unclearCross-Sectional

Awareness and knowledge of fibromyalgia among French rheumatologists and general practitioners.

Blotman, F, Thomas, E, Myon, E et al.·Clinical and experimental rheumatology·2005

This study asked French doctors (both general practitioners and specialists called rheumatologists) how much they knew about fibromyalgia, a condition with widespread muscle pain and fatigue. The results showed that most doctors had never formally learned about this condition in medical school, and many did not fully recognize it as a legitimate disease. The study highlights that doctors need better training to understand and properly diagnose fibromyalgia.

E2 ModerateCohortPEM not requiredObservational

Chronic fatigue syndrome and other fatiguing illnesses in adolescents: a population-based study.

Jones, James F, Nisenbaum, Rosane, Solomon, Laura et al.·The Journal of adolescent health : official publication of the Society for Adolescent Medicine·2004

Researchers surveyed families in Kansas to see how many adolescents (ages 12-17) had chronic fatigue syndrome (CFS) or other long-term fatigue illnesses. They found that CFS is much less common in teenagers than in adults. When both teens and their parents were carefully evaluated by doctors, none of the participating teenagers actually met the full definition of CFS, though some had prolonged fatigue from other causes.

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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.