Groven, Nina, Reitan, Solveig Klæbo, Fors, Egil Andreas et al. · Psychoneuroendocrinology · 2021 · DOI
This study examined a specific metabolic pathway in the blood called the kynurenine pathway, which affects how the brain functions. Researchers compared blood samples from people with ME/CFS, people with fibromyalgia, and healthy people to see if the chemical breakdown products in this pathway differed. They found that the balance of certain chemicals was different in people with these conditions, and these differences may relate to fatigue and pain symptoms.
This research provides biological evidence that ME/CFS and fibromyalgia involve measurable alterations in a brain-active metabolic pathway. Understanding these metabolic differences may eventually lead to new diagnostic biomarkers or targeted treatments, and strengthens the scientific case that these conditions have objective biological underpinnings rather than purely psychological causes.
This study does not prove that kynurenine metabolite imbalances *cause* ME/CFS or fibromyalgia—it only shows they are associated. The cross-sectional design cannot establish causation or determine whether metabolite changes are a cause, consequence, or bystander phenomenon. Results apply only to women aged 18–60 and may not generalize to men, adolescents, or older patients.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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