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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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266 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

101–120 of 266 studies

E2 ModerateCohortPEM not requiredCross-Sectional

[Sleep disturbances - an important factor in combination 'minor' symptoms of multiple sclerosis].

Yakupov, E Z, Troshina, Yu V·Zhurnal nevrologii i psikhiatrii imeni S.S. Korsakova·2017

This study looked at sleep problems in 54 people with multiple sclerosis (MS) compared to 54 healthy people. Researchers found that people with MS had much more trouble sleeping, and that poor sleep was connected to anxiety, depression, and fatigue. The study suggests that sleep disturbances may play an important role in how MS affects quality of life and fatigue symptoms.

E2 ModerateCohortPEM unclearCross-Sectional

Sleep Quality in Adolescents With Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME).

Josev, Elisha K, Jackson, Melinda L, Bei, Bei et al.·Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine·2017

This study examined sleep problems in teenagers with ME/CFS compared to healthy teenagers. Researchers found that teens with ME/CFS took longer to fall asleep, spent more total time in bed, slept longer overall, woke up later, and reported feeling their sleep was of poorer quality. Anxiety levels were also higher in the ME/CFS group and were connected to worse sleep quality in both groups.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Fatigue and psychosocial variables in autoimmune rheumatic disease and chronic fatigue syndrome: A cross-sectional comparison.

Ali, Sheila, Matcham, Faith, Irving, Katherine et al.·Journal of psychosomatic research·2017

This study compared how people with ME/CFS and people with autoimmune rheumatic diseases (like rheumatoid arthritis) experience fatigue and cope with their symptoms. The researchers found that people with ME/CFS were more fatigued, had worse sleep, and were more likely to avoid activities and struggle with accepting their illness, while people with rheumatic diseases were more likely to worry about damage to their bodies. This suggests that fatigue in these different conditions may need different treatment approaches.

E2 ModerateCohortPEM not requiredObservational

Specialist treatment of chronic fatigue syndrome/ME: a cohort study among adult patients in England.

Collin, Simon M, Crawley, Esther·BMC health services research·2017

This study looked at how 952 ME/CFS patients fared after receiving treatment at 11 specialist NHS clinics in England. One year after starting treatment, about 27% felt much better, 37% felt a little better, but 20% felt the same or worse. Even 2-5 years later, 85% of patients still had ME/CFS symptoms, showing that this is a long-lasting condition that often continues despite specialist care.

SleepPain and Sensitization

E2 ModerateBehavioralPEM not requiredCase-Control

Stressful Events in the Onset of Chronic Fatigue Syndrome.

Gimeno Pi, Iraida, Guitard Sein-Echaluce, M Luisa, Rosselló Aubach, Lluís et al.·Revista espanola de salud publica·2016

This study looked at whether stressful life events might trigger ME/CFS by comparing 77 people with the disease to 77 healthy people of similar age, sex, and education. Researchers found that certain stressful experiences—like pregnancy, domestic abuse, workplace bullying, eating disorders, car accidents, money problems, and sleep disruptions—occurred more often in people before they developed ME/CFS. The study suggests that identifying these stressful events in at-risk people might help doctors recognize ME/CFS earlier.

E2 ModerateCohortPEM not requiredObservational

Dry Eye Syndrome Risks in Patients With Fibromyalgia: A National Retrospective Cohort Study.

Chen, Chao-Hsien, Yang, Tse-Yen, Lin, Cheng-Li et al.·Medicine·2016

This study found that people with fibromyalgia are more likely to develop dry eye syndrome than people without fibromyalgia. Younger fibromyalgia patients (under 50) and those with sleep problems or other conditions like irritable bowel syndrome had even higher risks of developing dry eyes. The researchers used health insurance records from Taiwan to track over 25,000 fibromyalgia patients and compare them to over 100,000 people without fibromyalgia.

E2 ModerateCohortPEM not requiredLongitudinal

Subjective but Not Actigraphy-Defined Sleep Predicts Next-Day Fatigue in Chronic Fatigue Syndrome: A Prospective Daily Diary Study.

Russell, Charlotte, Wearden, Alison J, Fairclough, Gillian et al.·Sleep·2016

This study found that how people with ME/CFS feel about their sleep quality matters more for next-day fatigue than what sleep monitors actually measure. When patients reported poor sleep quality or felt their sleep wasn't refreshing, they experienced worse fatigue the following day. Interestingly, people who worried or felt anxious before bed reported worse sleep, and waking up in a bad mood partly explained why poor sleep led to more fatigue.

E2 ModerateCohortPEM requiredCross-Sectional

Case definitions integrating empiric and consensus perspectives.

Jason, Leonard A, McManimen, Stephanie, Sunnquist, Madison et al.·Fatigue : biomedicine, health & behavior·2016

This study looked at 556 ME/CFS patients from three countries to understand how doctors should diagnose this condition. The researchers found that patients fall into different groups based on their symptoms: some have chronic fatigue alone, some have fatigue with other medical reasons, and some have ME/CFS with additional symptoms like problems with exercise recovery, brain fog, and sleep issues. The groups with more specific ME/CFS symptoms were significantly more disabled than those with just general fatigue.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Factors determining fatigue in the chronic fatigue syndrome: a path analysis.

Tobback, Els, Hanoulle, Ignace, Mariman, An et al.·Acta clinica Belgica·2016

This study looked at how different factors—sleep quality, mood, and overall health—affect fatigue in ME/CFS patients. Researchers asked 167 patients to fill out questionnaires about their fatigue, sleep, personality traits, and quality of life. Surprisingly, they found that poor sleep directly harmed both physical and mental quality of life, but didn't necessarily increase fatigue scores on standard tests.

E2 ModerateCohortPEM not requiredCross-Sectional

Altered resting brain connectivity in persistent cancer related fatigue.

Hampson, Johnson P, Zick, Suzanna M, Khabir, Tohfa et al.·NeuroImage. Clinical·2015

This study used brain imaging to compare how the brains of breast cancer survivors with fatigue differ from those without fatigue. Researchers found that people experiencing persistent cancer-related fatigue showed different patterns of communication between brain regions, particularly involving areas linked to thinking about oneself and regulating sleep. These brain connectivity differences were associated with worse physical fatigue and poor sleep quality.

E2 ModerateCohortPEM not requiredCross-Sectional

Sleep characteristics, exercise capacity and physical activity in patients with chronic fatigue syndrome.

Aerenhouts, Dirk, Ickmans, Kelly, Clarys, Peter et al.·Disability and rehabilitation·2015

This study looked at how sleep problems and low activity levels are connected in people with ME/CFS. Researchers measured fitness capacity, sleep patterns, and daily activity in 42 women with ME/CFS and compared them to 24 healthy inactive women. People with ME/CFS slept more, spent more time in bed, had difficulty falling asleep and staying asleep, and were less physically active than the control group.

E2 ModerateCohortPEM not requiredCross-Sectional

A Cross Cultural Comparison of Disability and Symptomatology Associated with CFS.

Zdunek, Maria, Jason, Leonard A, Evans, Meredyth et al.·International journal of psychology and behavioral sciences·2015

This study compared ME/CFS symptoms and disability between patients in the United States and the United Kingdom to see if the illness looks different depending on where people live. Researchers found that UK patients reported more mental health problems, pain, memory/concentration issues, and immune symptoms, while US patients more often experienced sudden illness onset and attributed their illness to physical causes. The study suggests that ME/CFS may present somewhat differently across these two countries.

Cognitive ImpairmentPain and SensitizationSleep

E2 ModerateBehavioralPEM not requiredCross-Sectional

The Preinterventional Psychiatric History as a Major Predictor for a Reduced Quality of Life After Treatment of Unruptured Intracranial Aneurysms.

Fontana, Johann, Wenz, Ralf, Groden, Christoph et al.·World neurosurgery·2015

This study looked at patients who had surgery for unruptured brain aneurysms (weak blood vessel spots in the brain that hadn't bled yet) and compared them to patients who had surgery for brain tumors. The researchers found that patients with a history of psychiatric conditions before surgery reported worse quality of life and more chronic fatigue symptoms after surgery, but when they removed those patients from the analysis, the differences went away. This suggests that pre-existing mental health conditions, not the aneurysm or surgery itself, may explain poor outcomes.

E2 ModerateCohortPEM not requiredCross-Sectional

The association between daytime napping and cognitive functioning in chronic fatigue syndrome.

Gotts, Zoe M, Ellis, Jason G, Deary, Vincent et al.·PloS one·2015

This study looked at how sleep patterns, especially daytime napping, affect fatigue, sleepiness, and thinking ability in people with ME/CFS. Researchers asked 118 patients to keep a sleep diary for two weeks and complete daily assessments of their symptoms. They found that afternoon napping was linked to worse cognitive problems and increased daytime sleepiness, suggesting that when and how much patients nap may influence how well they can think and function.

SleepCognitive Impairment

E2 ModerateCohortPEM not requiredCross-Sectional

Slow wave sleep in the chronically fatigued: Power spectra distribution patterns in chronic fatigue syndrome and primary insomnia.

Neu, Daniel, Mairesse, Olivier, Verbanck, Paul et al.·Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology·2015

This study looked at the deepest, most restorative type of sleep in people with ME/CFS and primary insomnia to understand why both groups feel tired and don't feel rested despite sleeping. Researchers used special brain wave measurements during sleep and found that both groups had unusual patterns of very slow brain waves during deep sleep, even though they were getting normal or sometimes even extra amounts of deep sleep. The findings suggest that the problem may not be getting enough deep sleep, but rather that the quality or type of brain activity during that sleep is different.

E2 ModerateBehavioralPEM not requiredObservational

The role of insomnia in the treatment of chronic fatigue.

Kallestad, Håvard, Jacobsen, Henrik B, Landrø, Nils Inge et al.·Journal of psychosomatic research·2015

This study examined whether improving sleep problems (insomnia) could help people with chronic fatigue feel less tired and recover better from stress. Researchers worked with 122 people who had chronic fatigue and received a 3.5-week rehabilitation program focused on acceptance and commitment therapy. They found that patients whose insomnia improved also experienced greater improvements in fatigue and had better stress recovery, suggesting that treating sleep problems may be an important part of treating chronic fatigue.

E2 ModerateCohortPEM not requiredCross-Sectional

Chronic fatigue syndrome and fibromyalgia in diagnosed sleep disorders: a further test of the 'unitary' hypothesis.

Pejovic, Slobodanka, Natelson, Benjamin H, Basta, Maria et al.·BMC neurology·2015

This study looked at whether ME/CFS and fibromyalgia are actually the same condition or different disorders. Researchers compared patients with sleep-breathing problems, sleep insomnia, and healthy controls, measuring how often each group had ME/CFS, fibromyalgia, or both. They found that while both conditions occurred in sleep disorder patients, fibromyalgia was much more common in insomnia patients, whereas ME/CFS appeared in both groups equally—suggesting these may be separate conditions with different causes.

E2 ModerateBehavioralPEM not requiredObservational

The pre-interventional psychiatric history - an underestimated confounder in benign intracranial lesions studies.

Wenz, H, Wenz, R, Groden, C et al.·Clinical neurology and neurosurgery·2015

This study looked at 103 patients who had surgery for benign brain tumors or aneurysms and were physically recovered afterward. Researchers found that patients with a history of psychiatric conditions before surgery reported worse quality of life, more sleep problems, more fatigue symptoms, and more PTSD symptoms after surgery compared to those without prior psychiatric history—even though both groups had similar physical recovery.

E2 ModerateCohortPEM not requiredCross-Sectional

Non-REM sleep EEG power distribution in fatigue and sleepiness.

Neu, Daniel, Mairesse, Olivier, Verbanck, Paul et al.·Journal of psychosomatic research·2014

This study compared brain wave patterns during sleep between people with ME/CFS, people with sleep apnea, and healthy controls. Researchers found that ME/CFS patients show a different pattern of brain activity during sleep compared to those with sleep apnea, which may help explain why ME/CFS fatigue doesn't improve with rest like normal sleepiness does.

E2 ModerateCohortPEM not requiredLongitudinal

The role of hypocortisolism in chronic fatigue syndrome.

Nijhof, Sanne L, Rutten, Juliette M T M, Uiterwaal, Cuno S P M et al.·Psychoneuroendocrinology·2014

This study looked at stress hormone levels (cortisol) in adolescents with ME/CFS by measuring saliva samples. Teenagers with ME/CFS had lower cortisol levels than healthy peers, and those who improved with treatment showed their cortisol levels normalize, while those who didn't recover showed little change. The findings suggest that restoration of normal cortisol production during treatment may be linked to better outcomes.

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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.