Evidence browser

Measuring substantial reductions in activity.

Schafer, Charles, Evans, Meredyth, Jason, Leonard A et al.·Journal of prevention & intervention in the community·2015

ME/CFS diagnosis requires showing a significant drop in daily activities, but doctors have struggled to measure this fairly. This study looked at different ways to measure activity levels—including work, quality of life surveys, and activity trackers—to find which method works best. The researchers found that tracking current work activities was the most useful way to show the substantial reduction in functioning that ME/CFS patients experience.

Sympathetic activation is associated with increased IL-6, but not CRP in the absence of obesity: lessons from postural tachycardia syndrome and obesity.

Okamoto, Luis E, Raj, Satish R, Gamboa, Alfredo et al.·American journal of physiology. Heart and circulatory physiology·2015

This study looked at how an overactive nervous system relates to inflammation in the body. Researchers compared people with POTS (a condition causing increased heart rate when standing) to healthy controls, both lean and obese. They found that an overactive nervous system was linked to higher levels of IL-6, a marker of inflammation, even in people without obesity—but only obesity combined with nervous system overactivity produced high CRP, another inflammation marker.

E2 ModerateBehavioralPEM not requiredCross-Sectional

A comparison of patients with Q fever fatigue syndrome and patients with chronic fatigue syndrome with a focus on inflammatory markers and possible fatigue perpetuating cognitions and behaviour.

Keijmel, Stephan P, Saxe, Johanna, van der Meer, Jos W M et al.·Journal of psychosomatic research·2015

This study compared people with Q fever fatigue syndrome (a fatigue illness that develops after a specific infection) with people with ME/CFS to see if they were similar. Researchers found that both groups experienced similar levels of fatigue and emotional distress, but had some differences in their backgrounds and how they thought about their symptoms. The study suggests that physical activity might play a role in fatigue for both conditions, and that treatments focusing on behavior changes could potentially help people with Q fever fatigue syndrome.

E2 ModerateBehavioralPEM not requiredObservational

The role of the partner and relationship satisfaction on treatment outcome in patients with chronic fatigue syndrome.

Verspaandonk, J, Coenders, M, Bleijenberg, G et al.·Psychological medicine·2015

This study looked at how a patient's partner and their relationship quality affect how well cognitive behavioural therapy (CBT) works for ME/CFS. Researchers found that when partners were overly helpful or protective (called 'solicitous responses'), patients were less likely to improve significantly from their fatigue and disability. The study suggests that addressing how partners respond to the illness during treatment may be important for better outcomes.

Interventions

Cytokines in the cerebrospinal fluids of patients with chronic fatigue syndrome/myalgic encephalomyelitis.

Peterson, D, Brenu, E W, Gottschalk, G et al.·Mediators of inflammation·2015

Researchers tested cerebrospinal fluid (the fluid around the brain and spinal cord) from ME/CFS patients and healthy controls to see if immune chemicals called cytokines were different. Out of 27 different immune chemicals tested, they found that only one—called IL-10—was lower in ME/CFS patients. This suggests that immune system problems in the brain and nervous system may play a role in ME/CFS symptoms.

E2 ModerateCohortPEM not requiredCase-Control

Early menopause and other gynecologic risk indicators for chronic fatigue syndrome in women.

Boneva, Roumiana S, Lin, Jin-Mann S, Unger, Elizabeth R·Menopause (New York, N.Y.)·2015

This study looked at whether gynecological conditions—like irregular periods, endometriosis, and early menopause—are more common in women with ME/CFS compared to healthy women. Researchers found that women with ME/CFS reported significantly more gynecological problems and surgeries, including hysterectomies (removal of the uterus) performed at younger ages. The findings suggest that gynecological issues may be connected to ME/CFS, though more research is needed to understand exactly how.

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.

Sleep

Pain and SensitizationCognitive Impairment

Associations Between Cognitive Performance and Pain in Chronic Fatigue Syndrome: Comorbidity with Fibromyalgia Does Matter.

Ickmans, Kelly, Meeus, Mira, De Kooning, Margot et al.·Pain physician·2015

This study looked at whether pain and thinking problems are connected in people with ME/CFS, and whether having fibromyalgia alongside ME/CFS changes this relationship. Researchers tested 48 patients with ME/CFS (some with fibromyalgia, some without) and 30 healthy people on memory and attention tasks, then measured their pain responses. They found that the type of pain problem matters: in patients with both conditions, a specific pain-processing difference predicted thinking problems, while in ME/CFS-only patients, reported pain levels predicted thinking problems.

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.

Sleep

Attention network test: assessment of cognitive function in chronic fatigue syndrome.

Togo, Fumiharu, Lange, Gudrun, Natelson, Benjamin H et al.·Journal of neuropsychology·2015

This study tested whether a computer-based attention test called the Attention Network Task (ANT) could measure thinking and processing speed problems in ME/CFS patients. Researchers compared 41 ME/CFS patients (some with depression, some without) to 29 healthy controls and found that ME/CFS patients took longer to respond to tasks, especially when the tasks were complex, even though they made the same number of mistakes as controls. This suggests that slowed thinking speed, rather than errors, may be the main cognitive problem in ME/CFS.

Cognitive Impairment

E2 ModerateBehavioralPEM not requiredCross-Sectional

Chronic fatigue syndrome and fibromyalgia in Canada: prevalence and associations with six health status indicators.

Rusu, C, Gee, M E, Lagacé, C et al.·Health promotion and chronic disease prevention in Canada : research, policy and practice·2015

This study looked at how many Canadians have ME/CFS (chronic fatigue syndrome) or fibromyalgia, and how these conditions affect their overall health. Researchers surveyed over 59,000 Canadians and found that about 1.4% have ME/CFS and 1.5% have fibromyalgia, with some people having both conditions. People with these conditions reported significantly worse health than those without them, especially when they had other illnesses at the same time.

Functional limitations in functional somatic syndromes and well-defined medical diseases. Results from the general population cohort LifeLines.

Joustra, Monica L, Janssens, Karin A M, Bültmann, Ute et al.·Journal of psychosomatic research·2015

This large study of nearly 90,000 people compared how much functional somatic syndromes (like ME/CFS and fibromyalgia) affect quality of life and work ability compared to well-defined medical diseases (like multiple sclerosis and rheumatoid arthritis). The researchers found that people with functional somatic syndromes experience similar severe limitations in daily functioning and work as those with traditional medical diseases, challenging the idea that these conditions are less serious.

Plasma cytokine expression in adolescent chronic fatigue syndrome.

Wyller, Vegard Bruun, Sørensen, Øystein, Sulheim, Dag et al.·Brain, behavior, and immunity·2015

This study measured inflammation markers called cytokines in the blood of 120 adolescents with ME/CFS and compared them to 68 healthy young people. Despite CFS patients reporting significantly more fatigue and symptoms suggesting inflammation, the researchers found no differences in cytokine levels or inflammation patterns between the two groups. This suggests that the fatigue and symptoms in adolescent ME/CFS may not be caused by the type of low-grade inflammation in the blood that researchers had previously suspected.

E2 ModerateCohortPEM requiredObservational

Fatigue in adults with post-infectious fatigue syndrome: a qualitative content analysis.

Stormorken, Eva, Jason, Leonard A, Kirkevold, Marit·BMC nursing·2015

This study interviewed 26 adults with ME/CFS about their fatigue to better understand what they experience. The researchers found that fatigue in ME/CFS is not just tiredness—it's a complex, all-consuming symptom that gets much worse with even small activities and is accompanied by other symptoms like brain fog and pain. The fatigue also changes throughout the day and is triggered by physical activity, emotions, stress, and sometimes things patients don't even realize are triggering it.

Post-Exertional Malaise

Increased expression of activation antigens on CD8+ T lymphocytes in Myalgic Encephalomyelitis/chronic fatigue syndrome: inverse associations with lowered CD19+ expression and CD4+/CD8+ ratio, but no associations with (auto)immune, leaky gut, oxidative and nitrosative stress biomarkers.

Maes, Michael, Bosmans, Eugene, Kubera, Marta·Neuro endocrinology letters·2015

This study examined immune cells called CD8+ T lymphocytes in ME/CFS patients and found they show higher levels of activation markers (CD38 and HLA-DR) compared to healthy people and those with regular fatigue. The researchers measured 139 ME/CFS patients, 65 with chronic fatigue, and 40 healthy controls, finding distinct immune patterns in ME/CFS that don't appear to be directly linked to inflammation, gut problems, or oxidative stress.

E2 ModerateCohortPEM requiredCross-Sectional

A new case definition of Neuro-Inflammatory and Oxidative Fatigue (NIOF), a neuroprogressive disorder, formerly known as chronic fatigue syndrome or Myalgic Encephalomyelitis: results of multivariate pattern recognition methods and external validation by neuro-immune biomarkers.

Maes, Michael·Neuro endocrinology letters·2015

This study looked at whether ME/CFS could be better understood by examining specific blood markers related to inflammation, oxidative stress, and immune activation. Researchers found two distinct groups of people with chronic fatigue—one group had significantly higher levels of problematic immune markers and inflammatory signs. The study proposes a new way to identify ME/CFS based on fatigue plus at least four of these symptoms: muscle tension, memory problems, sleep issues, digestive problems, headaches, or flu-like feelings.

BiomarkersImmune System

E2 ModerateBehavioralPEM unclearCross-Sectional

Prolonged fatigue in Ukraine and the United States: Prevalence and risk factors.

Friedberg, Fred, Tintle, Nathan, Clark, Jake et al.·Fatigue : biomedicine, health & behavior·2015

This study compared how common prolonged, disabling fatigue is in Ukraine versus the United States by surveying thousands of people in both countries. Researchers found that prolonged fatigue was more common in Ukraine (5.2%) than in the U.S. (3.7%), and identified different risk factors in each country—such as socioeconomic status, mood disorders, and various health conditions. Importantly, about one-fifth of people with prolonged fatigue had no other diagnosed medical or mental health condition.

Pain in people with chronic fatigue syndrome/myalgic encephalomyelitis: the role of traumatic stress and coping strategies.

Krzeczkowska, Anna, Karatzias, Thanos, Dickson, Adele·Psychology, health & medicine·2015

This study looked at pain in people with ME/CFS and how they cope with it. Researchers compared 27 people with ME/CFS to 27 healthy people and found that those with ME/CFS experienced more pain and had different coping strategies. People with ME/CFS who had severe pain were less likely to use helpful coping methods like accepting their situation or thinking positively about it.

Pain and Sensitization

E2 ModerateCohortPEM unclearObservational

Distinct plasma immune signatures in ME/CFS are present early in the course of illness.

Hornig, Mady, Montoya, José G, Klimas, Nancy G et al.·Science advances·2015

This study found that people with ME/CFS have distinctive patterns of immune system markers in their blood, but only early in the disease. Researchers compared blood samples from 52 people with early-stage ME/CFS to 348 healthy people and 246 people with long-standing ME/CFS. The early-stage group showed heightened immune activity that was not present in people who had been sick longer, suggesting the disease's immune profile changes over time.

BiomarkersImmune System

E2 ModerateCohortPEM not requiredCase-Control

Polymorphism in COMT is associated with IgG3 subclass level and susceptibility to infection in patients with chronic fatigue syndrome.

Löbel, Madlen, Mooslechner, Agnes Anna, Bauer, Sandra et al.·Journal of translational medicine·2015

This study looked at a genetic variation in a gene called COMT that affects how the body handles stress hormones. Researchers compared 74 ME/CFS patients with 76 healthy people and found that ME/CFS patients with a specific genetic variant (Met/Met) had higher stress hormone levels, weaker immune responses to certain infections, and got respiratory infections more often. This suggests that a person's genes may influence both their stress response and infection risk in ME/CFS.