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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 6,119 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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380 studies

E0 — Consensus628E1 — Replicated319E2 — Moderate2,756E3 — Preliminary2,416

ME/CFS4,009Long COVID207Post-infectious188Overlapping1,031

Required for diagnosis409Not specified / unclear2,190Not required3,520

Post-Exertional Malaise1,039Cognitive Dysfunction1,711Pain1,606Unrefreshing Sleep786Orthostatic Intolerance470

Cytokines812Gene Expression564Metabolomics469Neuroimaging464Autoantibodies454

Infection-Triggered1,157Long COVID Overlap563Pediatric494Severe227

Strong Phenotyping427Sex-Stratified325Severe ME Included115

Systematic Review256Meta-Analysis59RCT299

Peer-reviewed6,062Preprint3Unclear54

201–220 of 380 studies

E2 ModerateBehavioralPEM not requiredCross-Sectional

Attentional bias towards health-threat information in chronic fatigue syndrome.

Hou, Ruihua, Moss-Morris, Rona, Bradley, Brendan P et al.·Journal of psychosomatic research·2008

This study tested whether people with ME/CFS pay more attention to health-related threats compared to neutral information. Researchers used a simple computer task showing words and pictures related to health threats or neutral topics, and found that people with ME/CFS did indeed focus more on the health-threat information than healthy people did. This pattern of attention might help explain why some cognitive therapy approaches can be helpful for ME/CFS.

Cognitive Impairment

E2 ModerateCohortPEM not requiredCross-Sectional

Neuropsychological performance in persons with chronic fatigue syndrome: results from a population-based study.

Majer, Matthias, Welberg, Leonie A M, Capuron, Lucile et al.·Psychosomatic medicine·2008

This study compared thinking and motor skills in people with ME/CFS to healthy controls using computerized tests. People with ME/CFS showed slower reaction times and had more difficulty with memory tasks that involve holding and manipulating information in mind. These differences held up even after excluding people with psychiatric conditions or those taking medications that affect thinking.

Cognitive Impairment

E2 ModerateCohortPEM unclearObservational

Measuring health outcomes of a multidisciplinary care approach in individuals with chronic environmental conditions using an abbreviated symptoms questionnaire.

Fox, Roy, Sampalli, Tara, Fox, Jonathan·Journal of multidisciplinary healthcare·2008

This study looked at how well a multidisciplinary treatment program (combining different types of care) worked for people with multiple chemical sensitivity and related conditions like ME/CFS. Researchers tracked 292 patients over time and used a symptom questionnaire to measure improvement. They found that some symptoms like difficulty concentrating and tiredness improved quickly (within 6 months), while others like fatigue took longer to improve.

Cognitive Impairment

E2 ModerateCohortPEM not requiredCase-Control

A twin study of cognitive function in chronic fatigue syndrome: the effects of sudden illness onset.

Claypoole, Keith H, Noonan, Carolyn, Mahurin, Roderick K et al.·Neuropsychology·2007

This study compared 22 pairs of identical twins where one had ME/CFS and the other was healthy. Researchers gave both twins thinking and memory tests to see if ME/CFS affects the brain. Twins with ME/CFS had slower processing speed, weaker verbal memory, slower motor responses, and more difficulty with complex thinking tasks, even though they had the same genetic background as their healthy twin.

Cognitive Impairment

E2 ModerateCohortPEM unclearCross-Sectional

The experience of cancer-related fatigue and chronic fatigue syndrome: a qualitative and comparative study.

Bennett, Barbara, Goldstein, David, Friedlander, Michael et al.·Journal of pain and symptom management·2007

This study compared how fatigue affects women with cancer-related fatigue (after breast cancer treatment) versus women with ME/CFS. Both groups described very similar experiences: exhaustion, problems with thinking and memory, and mood changes. Women with ME/CFS also reported muscle pain and flu-like symptoms more often. The researchers found that these two conditions share a common set of disabling symptoms, suggesting they may involve similar underlying causes despite different triggers.

Cognitive Impairment

E2 ModerateCohortPEM not requiredCross-Sectional

Cognitive dysfunction relates to subjective report of mental fatigue in patients with chronic fatigue syndrome.

Capuron, Lucile, Welberg, Leonie, Heim, Christine et al.·Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology·2006

People with ME/CFS often report trouble thinking clearly, but researchers haven't always found proof of this on tests. This study found that cognitive problems are real, but mainly in patients who experience significant mental fatigue. When researchers gave cognitive tests to ME/CFS patients, those with high mental fatigue showed genuine difficulties with memory and attention, while those with low mental fatigue performed normally.

Cognitive Impairment

E2 ModerateCohortPEM unclearCross-Sectional

Sub-typing CFS patients on the basis of 'minor' symptoms.

Janal, Malvin N, Ciccone, Donald S, Natelson, Benjamin H·Biological psychology·2006

This study looked at 161 women with ME/CFS to see if different symptom patterns might point to different types of the illness. Researchers found three possible subtypes: one involving muscle and joint pain, one resembling infectious illness, and one affecting the brain and thinking. People with the brain-related subtype had more trouble with memory and attention, while those with the muscle/joint subtype were more likely to also have fibromyalgia.

Cognitive Impairment

E2 ModerateCohortPEM not requiredCase-Control

Probing the working memory system in chronic fatigue syndrome: a functional magnetic resonance imaging study using the n-back task.

Caseras, Xavier, Mataix-Cols, David, Giampietro, Vincent et al.·Psychosomatic medicine·2006

Researchers used brain imaging to study how people with ME/CFS perform memory tasks. Although patients and healthy people did equally well on the tasks, their brains used different patterns of activity—patients showed unusual activation in certain brain regions during easier tasks and reduced activity in key memory areas during harder tasks. This suggests that people with ME/CFS may need to work harder mentally to achieve the same results.

Cognitive Impairment

E2 ModerateCohortPEM not requiredCross-Sectional

[Cognitive function and psychological characteristics of patients with chronic fatigue syndrome].

Li, Yong-jie, Gao, Xu-guang, Wang, De-Xin et al.·Zhonghua yi xue za zhi·2005

This study looked at how ME/CFS affects thinking and memory in 91 Chinese patients compared to 30 healthy people. Researchers found that 90% of ME/CFS patients had problems with memory and attention, and most also experienced depression, anxiety, and obsessive thoughts. The results show that ME/CFS causes real cognitive problems that are different from those seen in psychiatric illnesses alone.

Cognitive Impairment

E2 ModerateCohortPEM not requiredCross-Sectional

Exercise and cognitive performance in chronic fatigue syndrome.

Cook, Dane B, Nagelkirk, Paul R, Peckerman, Arnold et al.·Medicine and science in sports and exercise·2005

This study tested whether a 25-minute light exercise session affected thinking and memory skills in people with ME/CFS. Researchers found that people with ME/CFS alone showed slower thinking speed and less consistent performance on cognitive tests compared to healthy people, but light exercise did not make their thinking worse. Interestingly, people with ME/CFS plus fibromyalgia did not show these cognitive problems.

Cognitive Impairment

E2 ModerateCohortPEM not requiredCross-Sectional

[Clinical characteristics of patients with chronic fatigue syndrome: analysis of 82 cases].

Li, Yong-Jie, Wang, De-Xin, Bai, Xiao-Li et al.·Zhonghua yi xue za zhi·2005

This study examined 82 Chinese patients with ME/CFS to understand what symptoms they experience and what might be causing their illness. Researchers found that most patients had memory and attention problems alongside fatigue, many showed signs of anxiety or depression, and some had low levels of a substance called L-carnitine (which helps produce energy) or evidence of a viral infection. When patients took L-carnitine supplements, their levels improved and symptoms got better.

Cognitive Impairment

E2 ModerateBehavioralPEM not requiredLongitudinal

A 12-month follow-up study of self-management training for people with chronic disease: are changes maintained over time?

Barlow, J H, Wright, C C, Turner, A P et al.·British journal of health psychology·2005

A 12-month follow-up study tracked 171 people with various chronic diseases (including ME/CFS) who attended a lay-led self-management course. Reported improvements in self-efficacy, fatigue, mood, and symptom management seen at 4 months were observed to persist at 12 months, and participants continued using techniques they had learned. This is one study of a self-management course; individual responses vary, and the relevance to ME/CFS specifically requires further investigation.

Cognitive Impairment

E2 ModerateCohortPEM not requiredObservational

JP-8 jet fuel exposure and divided attention test performance in 1991 Gulf War veterans.

Bell, Iris R, Brooks, Audrey J, Baldwin, Carol M et al.·Aviation, space, and environmental medicine·2005

This study examined how exposure to low levels of jet fuel affected thinking and attention in Gulf War veterans who were chronically ill. Researchers tested veterans' reaction times on a computer task before and after brief exposures to either jet fuel fumes or clean air, done three times over three weeks. Veterans who were ill and had chemical sensitivities showed faster reaction times after jet fuel exposure, which the researchers suggest might indicate changes in brain chemistry rather than improved thinking.

Cognitive Impairment

E2 ModerateCohortPEM unclearCross-Sectional

Working memory deficits in chronic fatigue syndrome: differentiating between speed and accuracy of information processing.

Deluca, John, Christodoulou, Christopher, Diamond, Bruce J et al.·Journal of the International Neuropsychological Society : JINS·2004

This study tested how quickly people with ME/CFS can process information (like reading or hearing something fast) and how well they can hold information in their working memory (like remembering a phone number while writing it down). The researchers found that people with ME/CFS without mental health conditions had slower information processing speeds, but their memory ability was normal. Interestingly, people with ME/CFS who also had depression or anxiety showed similar results to healthy people.

Cognitive Impairment

E2 ModerateCohortPEM unclearObservational

[Biologically active food additives for correction of the chronic fatigue syndrome].

Dotsenko, V A, Mosiĭchuk, L V, Paramonov, A E·Voprosy pitaniia·2004

This study looked at whether a nutritional supplement made from beer yeast called 'Nagipol' might help people with ME/CFS. Researchers gave the supplement to patients and found improvements in fatigue, thinking ability, mood symptoms, and some blood markers. The authors suggest it could be useful as part of dietary treatment for ME/CFS, especially for patients who are overweight.

Cognitive Impairment

E2 ModerateCohortPEM not requiredLongitudinal

Illness and disability in Danish Chronic Fatigue Syndrome patients at diagnosis and 5-year follow-up.

Andersen, M M, Permin, H, Albrecht, F·Journal of psychosomatic research·2004

This study followed 33 people with ME/CFS for 5 years to see how their illness affected their daily lives. Researchers found that most people remained severely disabled, with very few experiencing meaningful recovery. While emotional well-being sometimes improved over time, problems like difficulty reading and allergies often got worse.

Cognitive Impairment

E2 ModerateCohortPEM not requiredCross-Sectional

Neuropsychological deficits in patients with chronic fatigue syndrome.

Busichio, Kim, Tiersky, Lana A, Deluca, John et al.·Journal of the International Neuropsychological Society : JINS·2004

This study tested how thinking and memory work in people with ME/CFS compared to healthy people. Researchers gave 141 ME/CFS patients and 76 healthy volunteers a series of brain function tests. They found that ME/CFS patients performed noticeably worse on tests measuring attention, processing speed, and motor skills, with some showing significant difficulties across multiple areas.

Cognitive Impairment

E2 ModerateCohortPEM not requiredCase-Control

Cognitive processing in monozygotic twins discordant for chronic fatigue syndrome.

Mahurin, Roderick K, Claypoole, Keith H, Goldberg, Jack H et al.·Neuropsychology·2004

This study tested thinking and processing speed in identical twins where one had ME/CFS and one didn't, compared to healthy people without the condition. Researchers found that both twin groups—even the healthy ones—were slower at tasks requiring quick thinking compared to unrelated healthy controls, but both groups performed equally well on untimed thinking tasks. This suggests that slower processing speed may run in families rather than being caused by ME/CFS itself.

Cognitive Impairment

E2 ModerateBehavioralPEM not requiredLongitudinal

Predictors of outcome in fatigued employees on sick leave: results from a randomised trial.

Huibers, Marcus J H, Bleijenberg, Gijs, van Amelsvoort, Ludovic G P M et al.·Journal of psychosomatic research·2004

This study followed 151 tired employees on sick leave for one year to see who recovered and who returned to work. The researchers found that about 43% of people stopped having persistent fatigue, and 62% went back to work. Interestingly, getting better from fatigue and returning to work were driven by different factors—people who recovered from fatigue tended to view their condition differently psychologically, while those who returned to work tended to be younger, male, and have fewer thinking/memory problems.

Cognitive Impairment

E2 ModerateBehavioralPEM not requiredCross-Sectional

Functional status, neuropsychological functioning, and mood in chronic fatigue syndrome (CFS): relationship to psychiatric disorder.

Tiersky, Lana A, Matheis, Robert J, Deluca, John et al.·The Journal of nervous and mental disease·2003

This study looked at how depression and anxiety affect people with ME/CFS. Researchers compared four groups: people with ME/CFS alone, people with ME/CFS plus mental health symptoms that started after CFS, people with ME/CFS plus mental health symptoms that started before CFS, and healthy controls. The main finding was that while mental health problems don't make the physical fatigue and weakness worse, they do make people feel more emotionally distressed—especially if those mental health issues came before the CFS diagnosis.

Cognitive Impairment

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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.