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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 6,167 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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277 studies

E0 — Consensus643E1 — Replicated320E2 — Moderate2,782E3 — Preliminary2,422

ME/CFS4,025Long COVID217Post-infectious189Overlapping1,050

Required for diagnosis414Not specified / unclear2,219Not required3,534

Post-Exertional Malaise1,064Cognitive Dysfunction1,735Pain1,620Unrefreshing Sleep799Orthostatic Intolerance478

Cytokines818Gene Expression567Metabolomics473Neuroimaging468Autoantibodies458

Infection-Triggered1,174Long COVID Overlap588Pediatric493Severe231

Strong Phenotyping438Sex-Stratified326Severe ME Included118

Systematic Review265Meta-Analysis60RCT300

Peer-reviewed6,110Preprint3Unclear54

121–140 of 277 studies

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 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

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 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

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.

Pain and SensitizationSleepCognitive Impairment

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 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 unclearObservational

Multivitamin mineral supplementation in patients with chronic fatigue syndrome.

Maric, Daniela, Brkic, Snezana, Tomic, Slavica et al.·Medical science monitor : international medical journal of experimental and clinical research·2014

This study tested whether taking a multivitamin and mineral supplement could help women with ME/CFS feel better. Thirty-eight women took the supplement for 2 months, and researchers measured changes in fatigue, sleep, headaches, and other symptoms. Most symptoms improved notably, including less fatigue and better sleep, though overall quality of life scores did not change.

SleepAutonomic Nervous System

E2 ModerateCohortPEM unclearCross-Sectional

[Impact of the fibromyalgia in the chronic fatigue syndrome].

Faro, Mónica, Sáez-Francàs, Naia, Castro-Marrero, Jesús et al.·Medicina clinica·2014

This study looked at nearly 1,000 ME/CFS patients to see how many also had fibromyalgia (a condition causing widespread pain and fatigue), and whether having both conditions made symptoms worse. They found that about half of the ME/CFS patients also had fibromyalgia, and those patients experienced higher levels of fatigue, pain, sleep problems, and cognitive difficulties. People with both conditions reported a much greater impact on their quality of life compared to those with ME/CFS alone.

SleepAutonomic Nervous SystemCognitive Impairment

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.

E2 ModerateCohortPEM not requiredLongitudinal

Obstructive sleep apnea increases the risk of bladder pain syndrome/interstitial cystitis: a population-based matched-cohort study.

Chung, Shiu-Dong, Lin, Ching-Chun, Liu, Shih-Ping et al.·Neurourology and urodynamics·2014

This study found that people with obstructive sleep apnea (OSA)—a condition where breathing stops repeatedly during sleep—are nearly 4 times more likely to develop bladder pain syndrome/interstitial cystitis (BPS/IC) compared to people without OSA. Researchers followed over 32,000 people in Taiwan for 3 years and tracked who developed BPS/IC. The findings suggest that sleep problems and bladder pain may be connected, and doctors should ask patients with sleep apnea about urinary symptoms.

E2 ModerateCohortPEM not requiredCross-Sectional

Heart rate variability during sleep and subsequent sleepiness in patients with chronic fatigue syndrome.

Togo, Fumiharu, Natelson, Benjamin H·Autonomic neuroscience : basic & clinical·2013

This study looked at how the heart's rhythm changes during sleep in ME/CFS patients compared to healthy people, and whether these changes relate to feeling more or less tired after sleep. Researchers found that some ME/CFS patients who woke up feeling sleepier had different heart rhythm patterns during deep sleep than healthy controls, even though standard sleep measurements looked normal. This suggests the nervous system's control of the heart during sleep might be disrupted in ME/CFS, which could contribute to unrefreshing sleep.

SleepAutonomic Nervous System

E2 ModerateCohortPEM not requiredCross-Sectional

Predictors and consequences of fatigue in prevalent kidney transplant recipients.

Chan, Winnie, Bosch, Jos A, Jones, David et al.·Transplantation·2013

This study looked at tiredness in people who have received kidney transplants and are doing well medically. Researchers found that nearly 6 out of 10 kidney transplant patients experience significant fatigue that affects their daily life and quality of life, yet most doctors weren't documenting this problem in their medical records. The fatigue levels were similar to those seen in chronic fatigue syndrome, and it was linked to factors like inflammation, kidney function decline, poor sleep, anxiety, and depression.

E2 ModerateCohortPEM not requiredCross-Sectional

Are there sleep-specific phenotypes in patients with chronic fatigue syndrome? A cross-sectional polysomnography analysis.

Gotts, Zoe M, Deary, Vincent, Newton, Julia et al.·BMJ open·2013

This study looked at sleep patterns in 343 people with chronic fatigue syndrome using overnight sleep monitoring machines. Researchers found that about 30% of patients had a separate sleep disorder, and the remaining patients fell into four different groups based on their sleep problems—some had trouble falling asleep, some had frequent sleep interruptions, some slept longer than average, and some had very short sleep with lots of waking. The findings suggest that people with ME/CFS have different types of sleep problems and may benefit from different sleep treatments based on their specific pattern.

E2 ModerateCohortPEM not requiredCross-Sectional

Temporal organization of rest defined by actigraphy data in healthy and childhood chronic fatigue syndrome children.

Kawabata, Minako, Ueno, Taro, Tomita, Jun et al.·BMC psychiatry·2013

This study looked at sleep and rest patterns in healthy children and children with chronic fatigue syndrome (CFS) using wristband activity trackers. The researchers found that when they looked at the patterns of rest and sleep separately—distinguishing between time spent out of bed versus in bed—children with CFS had different patterns compared to healthy children. This suggests that how the body organizes rest and activity may be disrupted in CFS.

E2 ModerateCohortPEM not requiredCross-Sectional

Subjective sleep quality and daytime sleepiness in a large sample of patients with chronic fatigue syndrome (CFS).

Mariman, A, Vogelaers, D, Hanoulle, I et al.·Acta clinica Belgica·2012

This study looked at sleep problems in 415 ME/CFS patients by asking them to complete questionnaires about sleep quality and daytime sleepiness. The researchers found that ME/CFS patients reported both poor sleep quality and high daytime sleepiness, but these two problems didn't always occur together—some patients had poor sleep quality without feeling sleepy during the day, and a smaller group resembled people with insomnia. The findings suggest that sleep problems in ME/CFS are complex and may affect different patients in different ways.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Long-term sickness absence among patients with chronic fatigue syndrome.

Knudsen, Ann Kristin, Henderson, Max, Harvey, Samuel B et al.·The British journal of psychiatry : the journal of mental science·2011

This study looked at ME/CFS patients who were on long-term sick leave from work and compared them to those still working. Patients taking sick leave had more severe physical fatigue and sleep problems than other patients. Interestingly, those on sick leave also tended to avoid situations they found embarrassing and rested more often as a coping strategy. The researchers suggest that helping patients manage embarrassment-related thoughts and avoidance behaviors might help them return to work.

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Or browse by topic

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.