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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 6,205 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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250 studies

E0 — Consensus654E1 — Replicated321E2 — Moderate2,807E3 — Preliminary2,423

ME/CFS4,040Long COVID224Post-infectious190Overlapping1,064

Required for diagnosis417Not specified / unclear2,251Not required3,537

Post-Exertional Malaise1,082Cognitive Dysfunction1,749Pain1,628Unrefreshing Sleep805Orthostatic Intolerance484

Cytokines821Gene Expression573Metabolomics477Neuroimaging472Autoantibodies460

Infection-Triggered1,182Long COVID Overlap604Pediatric496Severe232

Strong Phenotyping445Sex-Stratified330Severe ME Included119

Systematic Review272Meta-Analysis61RCT301

Peer-reviewed6,148Preprint3Unclear54

141–160 of 250 studies

E2 ModerateCohortPEM not requiredCase-Control

Assessment of vulvodynia symptoms in a sample of US women: a prevalence survey with a nested case control study.

Arnold, Lauren D, Bachmann, Gloria A, Rosen, Raymond et al.·American journal of obstetrics and gynecology·2007

This study looked at how common vulvodynia (chronic pain in the vulva) is among American women and found that about 4% currently experience it. Women with vulvodynia were more likely to also have other conditions like chronic fatigue syndrome, fibromyalgia, depression, and irritable bowel syndrome. Many women reported that the pain significantly affected their sexual life and daily activities.

Pain and Sensitization

E2 ModerateBehavioralPEM not requiredCase-Control

A case-control study of risk factors for arm pain presenting to primary care services.

Ryall, Claire, Coggon, David, Peveler, Robert et al.·Occupational medicine (Oxford, England)·2006

This study looked at why some people develop arm pain and sought medical help for it. Researchers compared 132 people with arm pain to 127 people without arm pain and found that anxiety, depression, health worry, and having other conditions like chronic fatigue syndrome were all strongly linked to arm pain. Some physical activities like repetitive wrist movements and carrying heavy items were also associated with arm pain, especially when there was a specific diagnosis.

Pain and Sensitization

E2 ModerateCohortPEM not requiredCross-Sectional

Reliability of physiological, psychological, and cognitive variables in chronic fatigue syndrome.

Wallman, Karen E, Morton, Alan R, Goodman, Carmel et al.·Research in sports medicine (Print)·2005

Researchers tested whether measurements of fatigue, mood, thinking ability, and physical performance in ME/CFS patients were reliable when checked weekly over four weeks. Most measurements were reliable and consistent, but fatigue ratings—both mental and physical—varied too much week-to-week to be fully trusted. Interestingly, how well people performed during exercise didn't match up well with their reported depression or mood, suggesting the problem may be in how the brain processes fatigue rather than actual muscle weakness.

Pain and Sensitization

E2 ModerateCohortPEM unclearCross-Sectional

Ambulatory monitoring of physical activity and symptoms in fibromyalgia and chronic fatigue syndrome.

Kop, Willem J, Lyden, Angela, Berlin, Ali A et al.·Arthritis and rheumatism·2005

This study used activity trackers to measure how much people with ME/CFS and fibromyalgia move during daily life, and whether their pain and fatigue change based on activity levels. The researchers found that patients with these conditions did less intense activity and experienced more pain and fatigue when they were less active, but interestingly, having pain or fatigue seemed to cause them to reduce activity rather than the other way around.

Pain and Sensitization

E2 ModerateCohortPEM not requiredCase-Control

Relationship between musculoskeletal symptoms and blood markers of oxidative stress in patients with chronic fatigue syndrome.

Vecchiet, Jacopo, Cipollone, Francesco, Falasca, Katia et al.·Neuroscience letters·2003

This study compared 21 people with ME/CFS to 20 healthy people and found that those with ME/CFS had signs of increased cellular damage (oxidative stress) and lower levels of protective molecules in their blood. People with ME/CFS also had more fatigue and their muscles were more sensitive to pain. The researchers found that the amount of cellular damage correlated with how fatigued people felt and how sensitive their muscles were.

Pain and Sensitization

E2 ModerateCohortPEM not requiredCase-Control

Health and functional status of twins with chronic regional and widespread pain.

Aaron, Leslie A, Arguelles, Lester M, Ashton, Suzanne et al.·The Journal of rheumatology·2002

This study looked at twins where one had chronic pain (either in one area or widespread) and the other did not, to understand how pain affects health and function independent of ME/CFS. Researchers found that chronic pain significantly worsens general health perception, physical functioning, and sleep quality, effects that remain even after accounting for ME/CFS. However, the mental health impact of pain appears closely linked to having ME/CFS symptoms together.

Pain and SensitizationSleep

E2 ModerateCohortPEM not requiredCross-Sectional

A tender sinus does not always mean rhinosinusitis.

Naranch, K, Park, Y-J, Repka-Ramirez, M S et al.·Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery·2002

This study measured how sensitive people's sinuses and skin are to pressure pain across different groups: healthy people, those with sinus infections or allergies, and people with ME/CFS. The researchers found that people with ME/CFS had much more sensitive sinuses and skin overall compared to healthy people, suggesting that ME/CFS causes widespread pain sensitivity rather than actual sinus infection.

Pain and Sensitization

E2 ModerateCohortPEM unclearCase-Control

Symptom factor analysis, clinical findings, and functional status in a population-based case control study of Gulf War unexplained illness.

Bourdette, D N, McCauley, L A, Barkhuizen, A et al.·Journal of occupational and environmental medicine·2001

Researchers surveyed over 2,000 Gulf War veterans and conducted detailed medical exams on 443 of them to look for unexplained health symptoms. They found that many veterans experienced overlapping symptoms—including cognitive problems, fatigue, and muscle pain—that resembled conditions like fibromyalgia and chronic fatigue syndrome, but they found few clear physical differences between sick and healthy veterans.

Pain and SensitizationCognitive Impairment

E2 ModerateCohortPEM unclearCross-Sectional

Multiple chemical sensitivity and chronic fatigue syndrome in British Gulf War veterans.

Reid, S, Hotopf, M, Hull, L et al.·American journal of epidemiology·2001

This study looked at how often ME/CFS and multiple chemical sensitivity (MCS—a condition where people react badly to everyday chemicals) occurred in British military personnel who served in the Gulf War. Researchers compared three groups: those deployed to the Gulf, those sent to Bosnia, and those who served during the Gulf War period but weren't deployed. They found that both conditions were more common in Gulf veterans, and MCS was strongly linked to pesticide exposure.

Pain and Sensitization

E2 ModerateCohortPEM not requiredCross-Sectional

Self-reported sensitivity to chemical exposures in five clinical populations and healthy controls.

Nawab, S S, Miller, C S, Dale, J K et al.·Psychiatry research·2000

This study asked 225 people—including those with ME/CFS, SAD, and other conditions, plus healthy volunteers—to report how sensitive they are to everyday chemical exposures like perfumes, cleaning products, and other odors. People with ME/CFS reported significantly higher chemical sensitivity than healthy controls, and women reported more sensitivity than men. The researchers suggest that chemical sensitivity may be connected to how the body's stress-response system (the HPA axis) functions.

Pain and Sensitization

E2 ModerateCohortPEM not requiredCross-Sectional

Odor perception: multiple chemical sensitivities, chronic fatigue, and asthma.

Caccappolo, E, Kipen, H, Kelly-McNeil, K et al.·Journal of occupational and environmental medicine·2000

This study tested whether people with chemical sensitivities, chronic fatigue, and asthma have unusually sensitive noses. Researchers measured how well different groups could smell odors and identify them. While people with chemical sensitivities didn't actually detect odors at lower levels than others, they did report feeling more physical symptoms and found certain smells more unpleasant than other groups did.

Pain and Sensitization

E2 ModerateCohortPEM not requiredCross-Sectional

Overlapping conditions among patients with chronic fatigue syndrome, fibromyalgia, and temporomandibular disorder.

Aaron, L A, Burke, M M, Buchwald, D·Archives of internal medicine·2000

This study found that ME/CFS, fibromyalgia, and temporomandibular disorder (TMD) often occur together in the same patients and share similar symptoms like pain, fatigue, and sleep problems. The researchers also discovered that patients with these conditions frequently experience other illnesses like irritable bowel syndrome and headaches—much more often than healthy people do. The study suggests these conditions may be connected in some way we don't yet fully understand.

Pain and SensitizationSleepCognitive Impairment

E2 ModerateBehavioralPEM unclearCross-Sectional

The role of depression in pain, psychophysiological syndromes and medically unexplained symptoms associated with chronic fatigue syndrome.

Morriss, R K, Ahmed, M, Wearden, A J et al.·Journal of affective disorders·1999

This study looked at whether depression makes ME/CFS symptoms worse. Researchers compared three groups: ME/CFS patients without depression, ME/CFS patients with depression, and people with depression alone. They found that depression did not increase pain, headaches, or other unexplained symptoms in ME/CFS patients, but it did make their social life more difficult.

Pain and Sensitization

E2 ModerateCohortPEM not requiredCross-Sectional

Prevalence of chronic fatigue and chemical sensitivities in Gulf Registry Veterans.

Kipen, H M, Hallman, W, Kang, H et al.·Archives of environmental health·1999

This study looked at symptoms reported by Gulf War veterans to see how many experienced chronic fatigue and chemical sensitivities. Researchers found that about 16% of veterans met the standard criteria for ME/CFS, about 13% had multiple chemical sensitivities, and a small percentage had both conditions. The findings suggest these conditions were common among Gulf War veterans, though the study was based only on questionnaire responses rather than medical exams.

Pain and Sensitization

E2 ModerateCohortPEM not requiredCross-Sectional

The relationship between fibromyalgia and interstitial cystitis.

Clauw, D J, Schmidt, M, Radulovic, D et al.·Journal of psychiatric research·1997

This study compared symptom patterns in people with fibromyalgia, interstitial cystitis (a bladder pain condition), and healthy people. Researchers found that fibromyalgia and IC patients reported very similar types of symptoms beyond their primary complaints, and both groups showed increased pain sensitivity throughout their bodies—not just in the areas they typically experienced pain.

Pain and Sensitization

E2 ModerateCohortPEM unclearObservational

Effect of noise stress on chronic fatigue syndrome patients.

Beh, H C·The Journal of nervous and mental disease·1997

This study looked at how noise affects people with ME/CFS, examining whether environmental sounds make their symptoms worse. The research observed how patients responded to noise stress as part of understanding the condition better. This type of research helps identify triggers that may worsen fatigue and other ME/CFS symptoms.

Pain and Sensitization

E2 ModerateCohortPEM unclearCross-Sectional

The localization of pain in chronic fatigue syndrome on a pain drawing according to grid areas.

Líndal, E, Bergmann, S, Thorlacius, S et al.·Perceptual and motor skills·1996

This study looked at where people with ME/CFS experience pain by having them mark painful areas on a body diagram divided into sections. The researchers wanted to understand the pattern of pain locations across different body regions in ME/CFS patients. This type of mapping can help doctors better understand how pain is distributed in the condition.

Pain and Sensitization

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 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 unclearCross-Sectional

High frequency of fibromyalgia in patients with chronic fatigue seen in a primary care practice.

Goldenberg, D L, Simms, R W, Geiger, A et al.·Arthritis and rheumatism·1990

This study looked at whether people with chronic fatigue also have fibromyalgia, a condition involving widespread muscle pain and tender points. Researchers examined 27 patients with debilitating fatigue lasting at least 6 months and found that 70% of them had the widespread pain and tender points typical of fibromyalgia. This suggests that many people with chronic fatigue may also have fibromyalgia.

Pain and Sensitization

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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.