ME/CFS Evidence Browser — Classified Studies on Myalgic Encephalomyelitis

2795 studies

101–120 of 2,795 studies

E2 ModerateCohortPEM not requiredCross-Sectional

The Diagnostic Journey of Dysautonomia Patients: Insights from a Patient-Reported Outcome Study.

O'Dell, John A, Walker, Ash, Latham, Andrew J et al.·Journal of patient experience·2025

This study followed 672 adults with dysautonomia (a condition where the nervous system that controls automatic body functions doesn't work properly) to understand how long it takes to get diagnosed and which doctors help with diagnosis. On average, it took 7.7 years for people to receive a diagnosis, and they often saw multiple types of doctors before getting answers. The study found that dysautonomia commonly occurs alongside other conditions like Ehlers-Danlos syndrome, mast cell disorders, and ME/CFS, which can make diagnosis even more confusing.

Autonomic Nervous SystemDiagnostics

E2 ModerateCohortPEM unclearLongitudinal

Characterization of Post-Viral Infection Behaviors Among Patients With Long COVID: Prospective, Observational, Longitudinal Cohort Analyses of Fitbit Data and Patient-Reported Outcomes.

Zhang, Tianmai M, Sharp, Sydney P, Scott, John D et al.·JMIR formative research·2025

Researchers gave 82 people with long COVID or ME/CFS Fitbit devices to track their physical activity, heart rate, and sleep for up to a year, while also asking them to report how they felt. They found that people who were less physically active reported worse fatigue, breathing problems, and physical function, and their symptoms worsened over time compared to those who remained more active. This suggests that activity levels may be related to symptom severity in long COVID, though the study couldn't prove that low activity causes worse symptoms.

Sleep

E2 ModerateCohortPEM not requiredObservational

Nonpelvic comorbid symptoms of 45 patients with pain of pelvic venous origin, before and after treatment.

Smith, Steven J, Smith, B Holly, Sichlau, Michael J et al.·Phlebology·2025

This study looked at 45 women with chronic pelvic pain caused by abnormal blood pooling in pelvic veins. These patients experienced many symptoms beyond pelvic pain—including brain fog, fatigue, migraines, constipation, and anxiety. After receiving a catheter-based procedure to fix the blood pooling, most of these systemic symptoms improved significantly (by 50% or more).

Pain and SensitizationAutonomic Nervous SystemCognitive Impairment

E2 ModerateCohortPEM unclearCross-Sectional

HERV activation segregates ME/CFS from fibromyalgia while defining a novel nosologic entity.

Giménez-Orenga, Karen, Martín-Martínez, Eva, Nathanson, Lubov et al.·eLife·2025

This study looked at special genetic materials called human endogenous retroviruses (HERVs) in the blood cells of women with ME/CFS, fibromyalgia, both conditions, or neither. The researchers found that the pattern of which HERVs were active could perfectly distinguish between these four groups—suggesting this could become a reliable blood test to diagnose these conditions. The study also found that ME/CFS patients had specific changes in immune cells that matched how severe their symptoms were.

BiomarkersImmune System

E2 ModerateCohortPEM unclearObservational

Functional and internalizing disorders co-aggregate with cardiometabolic and immune-related diseases within families: a population-based cohort study.

Steen, Olivier D, Bos, Martje, van Ockenburg, Sonja L et al.·BMC medicine·2025

This study found that ME/CFS, fibromyalgia, and irritable bowel syndrome tend to run in families alongside conditions like depression, anxiety, autoimmune diseases, and metabolic disorders. Researchers analyzed data from over 166,000 people in a Dutch population cohort to understand whether these conditions share common inherited risk factors. The findings suggest that the causes of functional disorders like ME/CFS may overlap with the causes of immune and metabolic diseases, which could point to new treatment approaches.

Immune System

E2 ModerateCohortPEM not requiredCross-Sectional

Prevalence and severity of neurologic symptoms in Long-COVID and the role of pre-existing conditions, hospitalization, and mental health.

Huff, Hanalise V, Roberts, Henry, Bartrum, Elizabeth et al.·Frontiers in neurology·2025

This study looked at neurological symptoms in 213 people with Long-COVID, examined 8 months after infection. Researchers found that fatigue, brain fog, unrefreshed sleep, and word-finding difficulties were very common and often severe. Importantly, these symptoms appeared to be caused by the virus itself rather than by pre-existing health conditions or how sick people were during acute infection.

Cognitive Impairment

E2 ModerateCohortPEM unclearRegistry-Resource

Unequal access to diagnosis of myalgic encephalomyelitis in England.

Samms, Gemma Louise, Ponting, Chris P·BMC public health·2025

This study examined NHS records from England to understand how many people have ME/CFS and whether diagnosis is fair across different groups. Researchers found that about 100,000 people in England have been officially diagnosed with ME/CFS, but the actual number may be much higher—around 404,000 in the UK. The diagnosis rates varied significantly depending on gender, age, ethnicity, and where people live, suggesting some patients are being missed.

Diagnostics

E2 ModerateBehavioralPEM not requiredObservational

Welfare benefit utilization for people with functional somatic disorder. A population-based cohort study.

Petersen, Marie Weinreich, Wellnitz, Kaare Bro, Carstensen, Tina Birgitte Wisbech et al.·Journal of psychosomatic research·2025

This study looked at how many weeks per year people with functional somatic disorder (FSD)—a condition with persistent physical symptoms that can't be explained by standard medical tests—used welfare benefits compared to people without FSD. Researchers in Denmark tracked about 9,600 people over 14 years and found that people with FSD used significantly more sickness benefits, unemployment benefits, and disability pensions than those without the condition. The findings show that FSD is a seriously disabling condition that affects people's ability to work and support themselves.

E2 ModerateCohortPEM requiredObservational

The Clinical Relevance of Mast Cell Activation in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Rohrhofer, Johanna, Ebner, Lilian, Schweighardt, Johannes et al.·Diagnostics (Basel, Switzerland)·2025

This study looked at whether mast cells—immune cells that release chemicals causing inflammation—play a role in ME/CFS. Researchers surveyed 687 ME/CFS patients and reviewed records from 383 others, finding that about 25% had signs of problematic mast cell activation. Importantly, patients with mast cell problems who received targeted treatment reported better symptom relief than those without mast cell involvement, suggesting this might be a treatable subtype of ME/CFS.

Immune SystemPost-Exertional Malaise

E2 ModerateCohortPEM unclearCross-Sectional

Quantifying the Degree of Fatigue in People Reporting Symptoms of Post-COVID-19 Syndrome: Results from a Rasch Analysis.

Mayo, Nancy, Brouillette, Marie-Josée, Fellows, Lesley K et al.·Physiotherapy Canada. Physiotherapie Canada·2025

Researchers in this study developed and tested a new questionnaire to measure fatigue severity in people with post-COVID-19 syndrome. The measure, called the PCS Fatigue Severity Measure V1, performed well in their analysis of 414 participants—it correlated strongly with other fatigue measures and distinguished between people still working and those on sick leave. However, this is early-stage research in a single Canadian cohort, and the authors note that further testing in other populations is needed to confirm the measure's reliability over time.

DiagnosticsPost-Exertional Malaise

E2 ModerateCohortPEM unclearCase-Control

People with Long COVID and ME/CFS Exhibit Similarly Impaired Dexterity and Bimanual Coordination: A Case-Case-Control Study.

Sanal-Hayes, Nilihan E M, Hayes, Lawrence D, Mclaughlin, Marie et al.·The American journal of medicine·2025

This study tested hand coordination and fine motor skills in people with long COVID and ME/CFS using a simple pegboard task where participants place small pegs into holes as quickly and accurately as possible. Both patient groups performed similarly to each other but notably worse than healthy people, suggesting that problems with hand coordination and dexterity are common to both conditions. The findings highlight that these motor difficulties deserve specific medical attention and treatment in both long COVID and ME/CFS patients.

E2 ModerateCohortPEM requiredCross-Sectional

Patient-reported treatment outcomes in ME/CFS and long COVID.

Eckey, Martha, Li, Peng, Morrison, Braxton et al.·Proceedings of the National Academy of Sciences of the United States of America·2025

This study asked nearly 4,000 ME/CFS and long COVID patients about their experiences with over 150 different treatments to see which ones helped them feel better. The researchers found that ME/CFS and long COVID are very similar illnesses with overlapping symptoms and that patients with each condition responded similarly to treatments. The study also discovered that different patient subgroups—like those with heart rate and blood pressure problems, or those with thinking and memory problems—benefited most from specific types of treatments.

Post-Exertional Malaise

E2 ModerateCohortPEM unclearCross-Sectional

Small fiber neuropathy in the post-COVID condition and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Clinical significance and diagnostic challenges.

Azcue, Naiara, Teijeira-Portas, Sara, Tijero-Merino, Beatriz et al.·European journal of neurology·2025

This study found that both long-COVID patients and people with ME/CFS show signs of damage to small nerve fibers in the eyes and altered sensation to heat, compared to healthy people. Researchers used specialized imaging and tests to measure nerve fiber structure and how well patients could detect temperature changes. The findings suggest that small fiber nerve damage may contribute to symptoms like pain and abnormal sensations in these conditions.

Autonomic Nervous System

E2 ModerateCohortPEM unclearObservational

Variation in Repeated Handgrip Strength Testing Indicates Submaximal Force Production in Patients With Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Popkirov, Stoyan·European journal of neurology·2025

This study looked at handgrip strength tests in ME/CFS patients and healthy people to understand why grip strength varies so much in ME/CFS. Researchers found that ME/CFS patients showed more inconsistency in their grip strength measurements compared to healthy controls, suggesting their bodies aren't producing maximum force even when asked to do so. This pattern indicates the problem may be related to how the brain controls muscles rather than the muscles themselves being permanently damaged.

Biomarkers

E2 ModerateCohortPEM not required

Two neurocognitive domains identified for patients with myalgic encephalomyelitis/chronic fatigue syndrome and post-acute sequelae of COVID-19.

Sandoval, Ariadna, Li, Mingqi, Jason, Leonard A·Frontiers in neurology·2025

This study looked at brain-related symptoms in over 2,600 people with ME/CFS and COVID long-haul (PASC), finding that their cognitive problems fall into two main categories. The first group includes classic memory and concentration difficulties, while the second group involves being overwhelmed by sensory input like loud noises or bright lights. The research suggests that doctors and researchers should pay more attention to sensory overload as an important part of cognitive problems in these conditions.

Cognitive Impairment

E2 ModerateCohortPEM not requiredCross-Sectional

Autonomic symptom burden, comorbidities and quality of life in women with Hypermobility Spectrum Disorders and hypermobile Ehlers-Danlos syndrome.

Collins Hutchinson, Meagan L, Liang, Emily, Fuster, Emily et al.·Autonomic neuroscience : basic & clinical·2025

This study looked at 84 women with connective tissue disorders (HSD/h-EDS) to understand how much autonomic nervous system problems they experience and how these affect their quality of life. The researchers found that these women had severe autonomic symptoms, with nearly 60% also having POTS and about 26% having ME/CFS. Overall, their quality of life was significantly worse than patients with other serious conditions like multiple sclerosis or rheumatoid arthritis.

Autonomic Nervous System

E2 ModerateCohortPEM requiredObservational

Low Vasopressin in Myalgic Encephalomyelitise/Chronic Fatigue Syndrome.

Huhmar, Helena M, Soinne, Lauri S, Bertilson, Bo Christer et al.·Endocrine practice : official journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists·2025

This study found that most people with ME/CFS have abnormally low levels of vasopressin, a hormone that helps your body control water balance and blood volume. The researchers measured this hormone and fluid markers in over 100 ME/CFS patients and discovered that 82% had vasopressin levels below the detectable range. This may help explain why many ME/CFS patients experience excessive thirst, frequent urination, and dizziness when standing up.

Autonomic Nervous System

E2 ModerateCohortPEM not requiredCross-Sectional

Abnormal breathing patterns and hyperventilation are common in patients with chronic fatigue syndrome during exercise.

Mancini, Donna M, Brunjes, Danielle L, Cook, Dane et al.·Frontiers in medicine·2025

Researchers studied how patients with ME/CFS breathe during exercise and found that many breathe abnormally in ways that healthy people do not. Specifically, 42% of ME/CFS patients showed irregular breathing patterns, and 32% were breathing too fast and too deeply (hyperventilation). These breathing problems were much more common in ME/CFS patients than in the healthy control group, suggesting that abnormal breathing may be contributing to the fatigue and breathlessness patients experience.

Post-Exertional Malaise

E2 ModerateCohortPEM not requiredCross-Sectional

Awareness and Perception of Myalgic Encephalomyelitis and Chronic Fatigue Syndrome Among Pain Specialists: A Questionnaire-Based Study.

Uygun, Gürsan Güneş, Gözükızıl, Salim Taner, Bilen, Ayşegül·Cureus·2025

This study asked pain doctors in Turkey about their knowledge of ME/CFS and how they evaluate and treat patients with the condition. The results show that many pain specialists aren't familiar with ME/CFS, and some hold misconceptions—like thinking it's a type of depression or that intense exercise will help. This matters because pain doctors could potentially help ME/CFS patients, but they need better education about the condition first.

Autonomic Nervous System

E2 ModerateCohortPEM not requiredCross-Sectional

Peripheral Levels of Selected Biomarkers in Patients with Post-Sarcoidosis Chronic Fatigue Syndrome.

Małujło-Balcerska, Elżbieta, Bączek, Karol, Górski, Witold et al.·Journal of inflammation research·2025

This study looked at 71 people with sarcoidosis (a disease that causes inflammation) to understand why some feel extremely tired even after their disease improves. Researchers measured inflammation markers in the blood and found that people with lingering fatigue had higher levels of a protein called IL-6 compared to those without fatigue. The findings suggest that low-grade inflammation may be keeping people fatigued even when their disease appears to be under control.

Immune System

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The Diagnostic Journey of Dysautonomia Patients: Insights from a Patient-Reported Outcome Study.

Characterization of Post-Viral Infection Behaviors Among Patients With Long COVID: Prospective, Observational, Longitudinal Cohort Analyses of Fitbit Data and Patient-Reported Outcomes.

Nonpelvic comorbid symptoms of 45 patients with pain of pelvic venous origin, before and after treatment.

HERV activation segregates ME/CFS from fibromyalgia while defining a novel nosologic entity.

Functional and internalizing disorders co-aggregate with cardiometabolic and immune-related diseases within families: a population-based cohort study.

Prevalence and severity of neurologic symptoms in Long-COVID and the role of pre-existing conditions, hospitalization, and mental health.

Unequal access to diagnosis of myalgic encephalomyelitis in England.

Welfare benefit utilization for people with functional somatic disorder. A population-based cohort study.

The Clinical Relevance of Mast Cell Activation in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Quantifying the Degree of Fatigue in People Reporting Symptoms of Post-COVID-19 Syndrome: Results from a Rasch Analysis.

People with Long COVID and ME/CFS Exhibit Similarly Impaired Dexterity and Bimanual Coordination: A Case-Case-Control Study.

Patient-reported treatment outcomes in ME/CFS and long COVID.

Small fiber neuropathy in the post-COVID condition and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Clinical significance and diagnostic challenges.

Variation in Repeated Handgrip Strength Testing Indicates Submaximal Force Production in Patients With Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Two neurocognitive domains identified for patients with myalgic encephalomyelitis/chronic fatigue syndrome and post-acute sequelae of COVID-19.

Autonomic symptom burden, comorbidities and quality of life in women with Hypermobility Spectrum Disorders and hypermobile Ehlers-Danlos syndrome.

Low Vasopressin in Myalgic Encephalomyelitise/Chronic Fatigue Syndrome.

Abnormal breathing patterns and hyperventilation are common in patients with chronic fatigue syndrome during exercise.

Awareness and Perception of Myalgic Encephalomyelitis and Chronic Fatigue Syndrome Among Pain Specialists: A Questionnaire-Based Study.

Peripheral Levels of Selected Biomarkers in Patients with Post-Sarcoidosis Chronic Fatigue Syndrome.

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