Janssens, Karin A M, Zijlema, Wilma L, Joustra, Monica L et al. · Psychosomatic medicine · 2015 · DOI
This study looked at how often mood and anxiety disorders occur in people with ME/CFS, fibromyalgia, and irritable bowel syndrome compared to people without these conditions. Researchers found that people with these syndromes do experience depression and anxiety more often than the general population, but most people with these conditions do not have a psychiatric disorder. ME/CFS patients had the highest rates of mood and anxiety problems among the three conditions studied.
This study provides epidemiological evidence that mood and anxiety disorders are genuine comorbidities in ME/CFS occurring at higher rates than in the general population, supporting the need for integrated psychiatric and somatic care. It also demonstrates that psychiatric symptoms are not the primary or sole feature of ME/CFS, countering historical misconceptions that these syndromes are purely psychogenic. Understanding these associations helps clinicians and patients recognize when additional mental health support may be beneficial.
This study does not prove that mood and anxiety disorders cause ME/CFS, nor does it prove that ME/CFS causes psychiatric illness—correlation does not establish causation, and cross-sectional design cannot determine temporal relationships. The study uses self-reported symptom data rather than confirmed clinical diagnoses for ME/CFS, which may introduce misclassification bias. The findings do not support the notion that psychiatric illness explains the core pathophysiology of ME/CFS, as most individuals with ME/CFS do not meet criteria for mood or anxiety disorders.
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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