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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

181–200 of 277 studies

E2 ModerateBehavioralPEM not requiredCross-Sectional

Chronic fatigue syndrome and seasonal affective disorder: comorbidity, diagnostic overlap, and implications for treatment.

Terman, M, Levine, S M, Terman, J S et al.·The American journal of medicine·1998

This study looked at whether ME/CFS symptoms get worse during winter months, similar to seasonal depression. Researchers asked 110 ME/CFS patients about their symptoms in summer and winter, and found that about one-third showed a seasonal pattern with winter worsening. This suggests that some ME/CFS patients might benefit from light therapy, a treatment commonly used for seasonal depression.

E2 ModerateCohortPEM not requiredCross-Sectional

Sleep abnormalities demonstrated by home polysomnography in teenagers with chronic fatigue syndrome.

Stores, G, Fry, A, Crawford, C·Journal of psychosomatic research·1998

Researchers used home sleep monitoring equipment to measure sleep quality in 18 teenagers with ME/CFS compared to healthy teens of the same age and gender. They found that teenagers with ME/CFS woke up much more frequently during the night—both for brief moments and longer periods—compared to the healthy group. These frequent sleep disruptions could help explain why young people with ME/CFS feel so exhausted during the day.

E2 ModerateCohortPEM not requiredCross-Sectional

Lack of seasonal variation of symptoms in patients with chronic fatigue syndrome.

García-Borreguero, D, Dale, J K, Rosenthal, N E et al.·Psychiatry research·1998

Many people experience changes in energy, mood, appetite, and sleep across different seasons, often feeling worse in winter. This study tested whether ME/CFS patients experience these same seasonal changes. The researchers found that ME/CFS patients actually show much less seasonal variation in their symptoms compared to healthy people, suggesting their fatigue and other symptoms stay relatively constant year-round rather than fluctuating with the seasons.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Correlations among Epworth Sleepiness Scale scores, multiple sleep latency tests and psychological symptoms.

Olson, L G, Cole, M F, Ambrogetti, A·Journal of sleep research·1998

This study looked at whether a simple questionnaire about daytime sleepiness (the Epworth Sleepiness Scale) actually measures the same thing as a more complex sleep test that measures how quickly people fall asleep. The researchers found that these two tests don't measure the same thing—the questionnaire is influenced by mood and psychological symptoms, while the objective sleep test is not.

E2 ModerateBehavioralPEM not requiredCross-Sectional

The relation of sleep difficulties to fatigue, mood and disability in chronic fatigue syndrome.

Morriss, R K, Wearden, A J, Battersby, L·Journal of psychosomatic research·1997

This study looked at sleep problems in 69 people with ME/CFS who had no mental health conditions and 58 with ME/CFS plus depression or anxiety. Researchers found that sleep difficulties are common in ME/CFS but are usually caused by the illness itself rather than depression. People with ME/CFS often took naps and woke up from pain, and when their sleep got worse, their ME/CFS symptoms often worsened too.

E2 ModerateCohortPEM not requiredCross-Sectional

Do patients with "pure" chronic fatigue syndrome (neurasthenia) have abnormal sleep?

Sharpley, A, Clements, A, Hawton, K et al.·Psychosomatic medicine·1997

This study compared sleep in 20 people with ME/CFS (who did not have depression, anxiety, or other sleep disorders) to 20 healthy people. Although ME/CFS patients reported feeling like they had poor, unrefreshing sleep and took daytime naps, objective sleep measurements showed surprisingly few differences—most patients actually slept a normal amount of time at night, though they spent longer lying awake after first falling asleep.

E2 ModerateCohortPEM unclearCross-Sectional

Sleep anomalies in the chronic fatigue syndrome. A comorbidity study.

Fischler, B, Le Bon, O, Hoffmann, G et al.·Neuropsychobiology·1997

This study examined sleep patterns in 49 ME/CFS patients compared to 20 healthy people using overnight sleep monitoring. Patients with ME/CFS had difficulty falling asleep and staying asleep, and spent less time in deep, restorative stage 4 sleep. These sleep problems were distinctive enough that researchers could correctly identify who had ME/CFS based on sleep patterns alone.

E2 ModerateBehavioralPEM not requiredObservational

An open study of the efficacy and adverse effects of moclobemide in patients with the chronic fatigue syndrome.

White, P D, Cleary, K J·International clinical psychopharmacology·1997

This study tested whether a medication called moclobemide could help people with ME/CFS. Researchers gave 49 patients the drug for 6 weeks and found small improvements in fatigue, depression, and anxiety. The medication worked better for patients who also had depression, with half of them feeling much better, compared to only about one-fifth of those without depression.

E2 ModerateCohortPEM unclearCase-Control

Somatomedin C (insulin-like growth factor I) levels in patients with chronic fatigue syndrome.

Bennett, A L, Mayes, D M, Fagioli, L R et al.·Journal of psychiatric research·1997

Researchers measured levels of somatomedin C (a growth-related hormone) in 49 ME/CFS patients and compared them to 30 healthy people. They found that ME/CFS patients had higher levels of this hormone than healthy controls. This is interesting because a similar condition called fibromyalgia shows the opposite pattern—lower levels of this hormone.

E2 ModerateCohortPEM unclearCross-Sectional

Insulin-like growth factor-I (somatomedin C) levels in chronic fatigue syndrome and fibromyalgia.

Buchwald, D, Umali, J, Stene, M·The Journal of rheumatology·1996

Researchers tested whether people with ME/CFS have lower levels of a growth hormone called IGF-I, which had previously been found to be low in fibromyalgia patients. They measured IGF-I levels in 15 people with ME/CFS, 15 with both ME/CFS and fibromyalgia, 27 with fibromyalgia alone, and 15 healthy volunteers. The study found no significant differences in IGF-I levels between any of the patient groups and healthy controls, suggesting that low IGF-I may not be a key feature of ME/CFS.

E2 ModerateCohortPEM not requiredCross-Sectional

Periodic K-alpha sleep EEG activity and periodic limb movements during sleep: comparisons of clinical features and sleep parameters.

MacFarlane, J G, Shahal, B, Mously, C et al.·Sleep·1996

This study examined a specific brain wave pattern during sleep called K-alpha activity and compared it to periodic leg movements during sleep. Researchers found that patients with K-alpha activity were predominantly women, younger, and more likely to have fibromyalgia and chronic fatigue syndrome, while also experiencing unrefreshing sleep, stomach problems, and muscle pain.

E2 ModerateCohortPEM not requiredCross-Sectional

Sleep disturbances and fatigue in women with fibromyalgia and chronic fatigue syndrome.

Schaefer, K M·Journal of obstetric, gynecologic, and neonatal nursing : JOGNN·1995

This study looked at sleep problems in women with fibromyalgia and chronic fatigue syndrome (CFS). Researchers found that both groups had significant sleep difficulties, and that trouble staying asleep was the most common sleep problem reported. There was a clear link between poor sleep and fatigue—women who slept poorly felt more tired.

E2 ModerateBehavioralPEM not requiredLongitudinal

Neuraesthenia revisited: ICD-10 and DSM-III-R psychiatric syndromes in chronic fatigue patients and comparison subjects.

Farmer, A, Jones, I, Hillier, J et al.·The British journal of psychiatry : the journal of mental science·1995

This study examined psychiatric conditions in people with chronic fatigue syndrome (CFS) using standardized diagnostic interviews. Most CFS patients met criteria for a condition called neuraesthenia (an older term for nerve exhaustion) and had higher rates of depression, anxiety, and sleep problems compared to healthy people. Interestingly, when researchers followed patients over about 11 months without giving specific treatment, some psychiatric symptoms improved on their own, while the core fatigue condition remained.

SleepDiagnostics

E2 ModerateCohortPEM not requiredCross-Sectional

Primary juvenile fibromyalgia syndrome and chronic fatigue syndrome in adolescents.

Bell, D S, Bell, K M, Cheney, P R·Clinical infectious diseases : an official publication of the Infectious Diseases Society of America·1994

This study looked at whether children diagnosed with chronic fatigue syndrome (CFS) also had fibromyalgia, a condition involving widespread muscle pain and tender points. Researchers found that about 30% of children with CFS met the criteria for fibromyalgia, and these children experienced more muscle pain, sleep problems, and neurological symptoms than those without fibromyalgia. The study suggests that CFS and fibromyalgia in children may be closely related or even the same condition.

Pain and SensitizationSleep

E2 ModerateCohortPEM not requiredObservational

Sleep disorders in patients with chronic fatigue.

Buchwald, D, Pascualy, R, Bombardier, C et al.·Clinical infectious diseases : an official publication of the Infectious Diseases Society of America·1994

This study looked at sleep problems in 59 people with chronic fatigue, most of whom had ME/CFS. Researchers found that 81% had at least one sleep disorder—most commonly sleep apnea—that might be treatable. Importantly, these sleep problems occurred whether or not people met the full criteria for ME/CFS, suggesting they are a separate issue worth investigating and treating.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Dimensional assessment of chronic fatigue syndrome.

Vercoulen, J H, Swanink, C M, Fennis, J F et al.·Journal of psychosomatic research·1994

This study asked 298 people with ME/CFS to fill out detailed questionnaires about how the illness affected them. Researchers found that ME/CFS affects people in nine different ways: mood and emotional health, ability to do daily activities, sleep quality, physical avoidance, thinking and memory problems, beliefs about what caused their illness, relationships and social life, confidence in their own abilities, and overall life satisfaction. Understanding these separate aspects could help doctors better assess and treat ME/CFS in individual patients.

SleepCognitive Impairment

E2 ModerateCohortPEM not requiredCross-Sectional

Alpha-delta sleep in patients with a chief complaint of chronic fatigue.

Manu, P, Lane, T J, Matthews, D A et al.·Southern medical journal·1994

This study looked at sleep patterns in 30 patients with chronic fatigue to understand what might be causing their exhaustion. Researchers found that a specific type of abnormal sleep pattern called 'alpha-delta sleep' appeared in about 26% of patients, but it was not clearly linked to ME/CFS or fibromyalgia. The study also found that one-third of the patients had other primary sleep disorders like sleep apnea that may have been contributing to their fatigue.

E2 ModerateCohortPEM not requiredCross-Sectional

Sleep disturbance in chronic fatigue syndrome.

Krupp, L B, Jandorf, L, Coyle, P K et al.·Journal of psychosomatic research·1993

This study looked at sleep problems in 72 people with ME/CFS, comparing them to people with multiple sclerosis and healthy volunteers. People with ME/CFS reported much worse sleep and fatigue than the other groups. When researchers used sleep monitoring equipment on some ME/CFS patients, they found that over half had treatable sleep disorders like sleep apnea or periodic leg movements during sleep.

E2 ModerateCohortPEM unclearCross-Sectional

Sleep, Epstein-Barr virus infection, musculoskeletal pain, and depressive symptoms in chronic fatigue syndrome.

Whelton, C L, Salit, I, Moldofsky, H·The Journal of rheumatology·1992

This study compared sleep patterns, virus exposure, and symptoms in 14 ME/CFS patients versus 12 healthy people. Patients reported sleep that didn't feel refreshing and had unusual brain wave patterns during sleep, but didn't show excessive daytime sleepiness. The study found no evidence that a chronic Epstein-Barr virus infection was causing the illness, but patients did have more widespread pain, tender points, and depression symptoms.

Pain and SensitizationSleep

E2 ModerateCohortPEM not requiredCase-Control

Sleep and symptoms in fibrositis syndrome after a febrile illness.

Moldofsky, H, Saskin, P, Lue, F A·The Journal of rheumatology·1988

This study looked at sleep patterns in people with fibromyalgia (a condition causing widespread pain and fatigue) who developed the condition after a fever, compared to people with fibromyalgia without a clear trigger and healthy volunteers. All fibromyalgia patients showed abnormal brain wave patterns during sleep that prevented their sleep from being truly restful, and they experienced similar muscle pain and tender points. This suggests that post-illness fibromyalgia shares the same sleep problems as other forms of fibromyalgia.

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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.