ME/CFS Evidence Browser — Classified Studies on Myalgic Encephalomyelitis

21–40 of 244 studies

E0 ConsensusReviewPEM unclearReview-Narrative

Fibromyalgia syndrome, idiopathic widespread persistent pain or syndrome of myalgic encephalomyelopathy (SME): what is its nature?

Mehendale, Anand W, Goldman, Mark P·Pain practice : the official journal of World Institute of Pain·2002

This review summarizes what scientists and doctors know about fibromyalgia and ME/CFS by examining research from the past 25 years. The authors looked at studies on symptoms, causes, blood test findings, brain imaging, and what patients reported about their experiences. They propose that these conditions may need to be understood in an entirely new way.

Pain and Sensitization

E0 ConsensusReviewPEM not requiredSystematic-Review

[What happens to the fibromyalgia syndrome?].

Maquet, D, Croisier, J L, Crielaard, J M·Annales de readaptation et de medecine physique : revue scientifique de la Societe francaise de reeducation fonctionnelle de readaptation et de medecine physique·2001

This review examined fibromyalgia, a condition causing widespread muscle and joint pain that lasts at least three months. The researchers found that fibromyalgia involves multiple problems working together: abnormal pain processing in the nervous system, poor sleep quality, muscle weakness, and hormonal imbalances. They concluded that treating fibromyalgia effectively requires a team approach addressing all these different issues, not just pain alone.

Pain and Sensitization

E1 ReplicatedTrialPEM not requiredCross-Sectional

Prevalence of Chronic Overlapping Pain Conditions in Participants With Chronic Low Back Pain Enrolled in a Pragmatic Trial of Mindfulness-Based Stress Reduction.

Miller, Vanessa Eve, Barnhill, Jessica, Greco, Carol M et al.·European journal of pain (London, England)·2025

This study looked at people with chronic low back pain to see how often they also have other long-term pain conditions like fibromyalgia, irritable bowel syndrome, and ME/CFS. Researchers found that 45% of people with back pain also had at least one other chronic pain condition, and these people reported more pain, fatigue, anxiety, and depression than those with back pain alone. The study suggests that chronic pain conditions often occur together and may share similar underlying causes.

Pain and Sensitization

E1 ReplicatedTrialPEM not requiredRCT

Efficacy of aquatic vs land-based therapy for pain management in women with fibromyalgia: a randomised controlled trial.

Rivas Neira, S, Pasqual Marques, A, Fernández Cervantes, R et al.·Physiotherapy·2024

This study compared two types of exercise therapy for women with fibromyalgia: exercising in a pool (aquatic therapy) versus exercising on land. Both groups did 60-minute exercise sessions three times a week for 12 weeks. Six weeks after the program ended, women who did aquatic therapy reported less pain and better sleep quality than those who exercised on land, suggesting that water-based exercise may be particularly helpful for fibromyalgia.

Pain and SensitizationSleep

E1 ReplicatedTrialPEM not requiredRCT

Effects of Yijinjing Qigongin Alleviating Fatigue, Sleep Quality, and Health Status on Patients with Chronic Fatigue Syndrome: A Randomized, Controlled, and Parallel Group Clinical Study.

Xie, Fangfang, Dong, Wenjun, Guan, Chong et al.·Complementary medicine research·2023

This study tested whether Yijinjing, an ancient Chinese exercise practice with 12 movements, could help patients with ME/CFS. Forty patients either practiced Yijinjing six times per week for 12 weeks or received cognitive behavioral education. The Yijinjing group showed greater improvements in fatigue, sleep quality, and quality of life compared to the education group.

Pain and SensitizationSleep

E1 ReplicatedTrialPEM not requiredRCT

Influence of Morphine and Naloxone on Pain Modulation in Rheumatoid Arthritis, Chronic Fatigue Syndrome/Fibromyalgia, and Controls: A Double-Blind, Randomized, Placebo-Controlled, Cross-Over Study.

Hermans, Linda, Nijs, Jo, Calders, Patrick et al.·Pain practice : the official journal of World Institute of Pain·2018

This study tested whether morphine and naloxone (a drug that blocks opioid effects) change how pain is processed in people with ME/CFS, fibromyalgia, rheumatoid arthritis, and healthy controls. Researchers measured pain sensitivity and pain relief in response to these medications using pressure tests and ischemic pain. They found that morphine slightly reduced pain sensitivity in patient groups similarly to placebo, but neither morphine nor naloxone significantly changed how the body's natural pain-relief system worked.

Pain and Sensitization

E1 ReplicatedTrialPEM not requiredObservational

Kinesiophobia and maladaptive coping strategies prevent improvements in pain catastrophizing following pain neuroscience education in fibromyalgia/chronic fatigue syndrome: An explorative study.

Malfliet, Anneleen, Van Oosterwijck, Jessica, Meeus, Mira et al.·Physiotherapy theory and practice·2017

This study looked at why some people with ME/CFS and fibromyalgia benefit more from a type of pain education (called pain neuroscience education) than others. The researchers found that patients who were very afraid of movement or who tended to worry a lot about their pain showed less improvement in their catastrophic thinking about pain after receiving this education. This suggests that for some patients, education alone may not be enough—they might need additional support to address their fears and worries.

Pain and SensitizationCognitive Impairment

E1 ReplicatedTrialPEM not requiredRCT

Muscle injections with lidocaine improve resting fatigue and pain in patients with chronic fatigue syndrome.

Staud, Roland, Kizer, Taylor, Robinson, Michael E·Journal of pain research·2017

Researchers tested whether injecting a numbing medication (lidocaine) into muscles could help ME/CFS patients with fatigue and pain. Compared to a placebo injection, lidocaine injections did reduce fatigue more effectively, and both types of injections reduced pain, depression, and anxiety. This suggests that signals from muscles themselves may play a role in ME/CFS symptoms.

Pain and Sensitization

E1 ReplicatedTrialPEM not requiredRCT

A Randomized, Controlled Trial of Wholistic Hybrid Derived From Eye Movement Desensitization and Reprocessing and Emotional Freedom Technique (WHEE) for Self-Treatment of Pain, Depression, and Anxiety in Chronic Pain Patients.

Benor, Daniel, Rossiter-Thornton, John, Toussaint, Loren·Journal of evidence-based complementary & alternative medicine·2017

This small pilot study tested whether a self-help technique called WHEE (combining eye movements with tapping) could help people with chronic pain, depression, and anxiety. Twenty-four patients with chronic pain conditions (including 17 with ME/CFS or fibromyalgia) were split into two groups: one received WHEE treatment for 6 weeks while the other waited. The WHEE group showed improvements in anxiety and depression compared to those who waited, and when the waiting group later tried WHEE, they also experienced less pain and depression.

Pain and Sensitization

E1 ReplicatedTrialPEM not requiredRCT

Acupuncture for chronic fatigue syndrome and idiopathic chronic fatigue: a multicenter, nonblinded, randomized controlled trial.

Kim, Jung-Eun, Seo, Byung-Kwan, Choi, Jin-Bong et al.·Trials·2015

This study tested whether acupuncture—a traditional practice involving thin needles inserted into the skin—could help people with chronic fatigue syndrome (CFS) and related fatigue conditions. Researchers divided 150 patients into three groups: two received different types of acupuncture for 4 weeks along with their usual care, while one group continued usual care alone. The acupuncture groups showed some improvements in fatigue, stress, and pain compared to the usual care group.

Pain and Sensitization

E1 ReplicatedTrialPEM not requiredRCT

Pain in chronic fatigue syndrome: response to rehabilitative treatments in the PACE trial.

Bourke, J H, Johnson, A L, Sharpe, M et al.·Psychological medicine·2014

This study looked at whether four different ME/CFS treatments—cognitive behavioral therapy (CBT), graded exercise therapy (GET), adaptive pacing therapy (APT), and standard medical care—could reduce pain symptoms. Both CBT and GET appeared to reduce muscle and joint pain more than APT or standard care, though the improvements were modest in size. Importantly, these pain improvements happened independently of whether fatigue got better.

Pain and Sensitization

E1 ReplicatedTrialPEM not requiredRCT

Isometric yoga improves the fatigue and pain of patients with chronic fatigue syndrome who are resistant to conventional therapy: a randomized, controlled trial.

Oka, Takakazu, Tanahashi, Tokusei, Chijiwa, Takeharu et al.·BioPsychoSocial medicine·2014

This study tested whether a gentle form of yoga called isometric yoga could help ME/CFS patients who hadn't improved with standard treatments. Thirty patients who had tried conventional therapies for at least six months were split into two groups: one continued their usual treatment, while the other added twice-weekly yoga sessions plus daily home practice. The yoga group showed significant improvements in fatigue and some also reported pain relief, with minimal side effects.

Pain and Sensitization

E1 ReplicatedTrialPEM not requiredRCT

Does acetaminophen activate endogenous pain inhibition in chronic fatigue syndrome/fibromyalgia and rheumatoid arthritis? A double-blind randomized controlled cross-over trial.

Meeus, Mira, Ickmans, Kelly, Struyf, Filip et al.·Pain physician·2013

This study tested whether acetaminophen (Tylenol) could help improve how the body's natural pain-blocking systems work in people with ME/CFS combined with fibromyalgia, compared to people with rheumatoid arthritis and healthy people. Researchers measured pain responses before and after taking acetaminophen or a placebo. The results were mixed: acetaminophen slightly helped pain thresholds in ME/CFS patients but actually made things slightly worse in arthritis patients and healthy controls, suggesting the drug affects different people very differently.

Pain and Sensitization

E1 ReplicatedTrialPEM not requiredRCT

Pain physiology education improves pain beliefs in patients with chronic fatigue syndrome compared with pacing and self-management education: a double-blind randomized controlled trial.

Meeus, Mira, Nijs, Jo, Van Oosterwijck, Jessica et al.·Archives of physical medicine and rehabilitation·2010

This study tested whether learning about how pain works in the nervous system could help people with ME/CFS who experience widespread pain. Researchers compared 48 patients who received either a 30-minute pain education session or standard pacing/self-management education. The group that learned about pain physiology showed better understanding of their pain and less worry and rumination about it right after the session.

Pain and Sensitization

E2 ModerateBehavioralPEM not requiredCase-Control

Increased Disease Burden in Irritable Bowel Syndrome With Comorbid Conditions and Psychiatric Diagnoses in a Multinational European Cohort: Results From the DISCOvERIE Project.

Midenfjord, Irina, Khadija, Mahrukh, Sundelin, Elias et al.·United European gastroenterology journal·2026

This study looked at 607 patients with irritable bowel syndrome (IBS) across nine European centers to understand how other conditions—like anxiety, depression, fibromyalgia, and chronic fatigue syndrome—affect their symptoms and overall health. Patients who had IBS along with one or more of these comorbid conditions experienced more severe digestive symptoms, mood problems, and fatigue than those with IBS alone. The more comorbidities someone had, the worse their symptoms became.

Pain and Sensitization

E2 ModerateCohortPEM not requiredLongitudinal

Long COVID longitudinal symptoms burden clusters within a national community-based cohort.

Shen, Yanhan, Shahn, Zach, Robertson, McKaylee M et al.·BMC infectious diseases·2026

This study followed over 500 people with long COVID for up to a year, tracking their symptoms over time. Researchers identified three groups based on symptom burden: one with persistent severe symptoms (including fatigue, brain fog, post-exertional malaise, and pain), one with moderate symptoms that improved, and one with minimal symptoms. The findings are preliminary and based on self-reported data, so the stability and generalisability of these groups to other long COVID populations remain to be confirmed.

Pain and SensitizationSleepAutonomic Nervous SystemCognitive Impairment

E2 ModerateCohortPEM unclearLongitudinal

Two-timepoint multidomain follow-up of post-COVID condition and ME/CFS: overlapping autonomic, small-fiber, and cognitive changes.

Azcue, N, Barranco, C, Tijero-Merino, B et al.·Journal of translational medicine·2026

Researchers compared 21 people with post-COVID condition and 17 people with ME/CFS over about 2.5 years, measuring nerve function, autonomic symptoms, and cognitive performance. They observed that both groups showed similar patterns of changes over time—including worsening processing speed and cold sensation sensitivity, but improving heat sensation thresholds and verbal memory. While the two conditions appeared increasingly alike on follow-up testing, the study does not establish whether they are truly the same disease or simply share overlapping symptoms.

Pain and SensitizationAutonomic Nervous SystemDiagnosticsCognitive Impairment

E2 ModerateBehavioralPEM not requiredObservational

Prevalence of Bodily Distress Syndrome and Prediction of Patient Outcomes: Cohort Study of 3762 Individuals With Persistent Pain.

Landmark, Live, Sunde, Hans Fredrik, Fors, Egil A et al.·European journal of pain (London, England)·2026

This study looked at how multiple physical symptoms often occur together in people with chronic pain, using a framework called Bodily Distress Syndrome (BDS). Among 3,762 people attending a specialized pain clinic, 92.5% showed moderate to severe BDS, and those with BDS experienced more severe symptoms and psychological stress. After one year, people with BDS improved less and reported less benefit from treatment compared to those without BDS.

Pain and Sensitization

E2 ModerateCohortPEM unclearCross-Sectional

Chronic Pain Prevalence, Characteristics, and Impact in United States Adults With Chronic Fatigue Syndrome/Myalgic Encephalomyelitis.

Adamowicz, Jenna L, Sirotiak, Zoe, Lendvai, Dora et al.·Pain management nursing : official journal of the American Society of Pain Management Nurses·2026

This study looked at how common chronic pain is in people with ME/CFS and how it affects their lives. Researchers found that about 7 out of 10 people with ME/CFS also experience chronic pain lasting months or longer. People with both ME/CFS and chronic pain reported more depression, anxiety, and difficulty with daily activities compared to people who only have chronic pain.

Pain and Sensitization

E2 ModerateBehavioralPEM not requiredCross-Sectional

Disentangling comorbidity: symptom dimensions of internalizing and functional disorders in a large general population sample.

Saini, Urvi, Aggen, Steven H, Oldehinkel, Albertine J et al.·BMC psychiatry·2026

This study looked at how symptoms of depression, anxiety, ME/CFS, fibromyalgia, and irritable bowel syndrome overlap in over 100,000 people. Researchers found that these conditions share common symptoms like fatigue, sleep problems, and difficulty concentrating—which they call 'general malaise'—rather than being completely separate diseases. Understanding these shared symptoms may help explain why people often have multiple conditions at the same time.

Pain and SensitizationCognitive Impairment

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Fibromyalgia syndrome, idiopathic widespread persistent pain or syndrome of myalgic encephalomyelopathy (SME): what is its nature?

[What happens to the fibromyalgia syndrome?].

Prevalence of Chronic Overlapping Pain Conditions in Participants With Chronic Low Back Pain Enrolled in a Pragmatic Trial of Mindfulness-Based Stress Reduction.

Efficacy of aquatic vs land-based therapy for pain management in women with fibromyalgia: a randomised controlled trial.

Effects of Yijinjing Qigongin Alleviating Fatigue, Sleep Quality, and Health Status on Patients with Chronic Fatigue Syndrome: A Randomized, Controlled, and Parallel Group Clinical Study.

Influence of Morphine and Naloxone on Pain Modulation in Rheumatoid Arthritis, Chronic Fatigue Syndrome/Fibromyalgia, and Controls: A Double-Blind, Randomized, Placebo-Controlled, Cross-Over Study.

Kinesiophobia and maladaptive coping strategies prevent improvements in pain catastrophizing following pain neuroscience education in fibromyalgia/chronic fatigue syndrome: An explorative study.

Muscle injections with lidocaine improve resting fatigue and pain in patients with chronic fatigue syndrome.

A Randomized, Controlled Trial of Wholistic Hybrid Derived From Eye Movement Desensitization and Reprocessing and Emotional Freedom Technique (WHEE) for Self-Treatment of Pain, Depression, and Anxiety in Chronic Pain Patients.

Acupuncture for chronic fatigue syndrome and idiopathic chronic fatigue: a multicenter, nonblinded, randomized controlled trial.

Pain in chronic fatigue syndrome: response to rehabilitative treatments in the PACE trial.

Isometric yoga improves the fatigue and pain of patients with chronic fatigue syndrome who are resistant to conventional therapy: a randomized, controlled trial.

Does acetaminophen activate endogenous pain inhibition in chronic fatigue syndrome/fibromyalgia and rheumatoid arthritis? A double-blind randomized controlled cross-over trial.

Pain physiology education improves pain beliefs in patients with chronic fatigue syndrome compared with pacing and self-management education: a double-blind randomized controlled trial.

Increased Disease Burden in Irritable Bowel Syndrome With Comorbid Conditions and Psychiatric Diagnoses in a Multinational European Cohort: Results From the DISCOvERIE Project.

Long COVID longitudinal symptoms burden clusters within a national community-based cohort.

Two-timepoint multidomain follow-up of post-COVID condition and ME/CFS: overlapping autonomic, small-fiber, and cognitive changes.

Prevalence of Bodily Distress Syndrome and Prediction of Patient Outcomes: Cohort Study of 3762 Individuals With Persistent Pain.

Chronic Pain Prevalence, Characteristics, and Impact in United States Adults With Chronic Fatigue Syndrome/Myalgic Encephalomyelitis.

Disentangling comorbidity: symptom dimensions of internalizing and functional disorders in a large general population sample.

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