Schur, Ellen A, Afari, Niloofar, Furberg, Helena et al. · Journal of general internal medicine · 2007 · DOI
This study looked at how often nine conditions—including ME/CFS, fibromyalgia, depression, and others—occur together in the same people. Researchers found that these conditions overlap far more than would happen by chance, suggesting they may share common underlying causes. The study identified four different groups of people based on their condition patterns, with one small group having nearly all nine conditions and experiencing the worst health outcomes.
For ME/CFS patients and researchers, this study provides evidence that the high rates of comorbidity with psychiatric and other medically unexplained conditions are not random but suggest a genuine shared biological or environmental basis. Understanding these comorbidity patterns can help clinicians recognize ME/CFS clusters and avoid misattribution of symptoms to psychiatric causes alone, improving diagnosis and treatment strategies.
This study does not establish causality—it only shows that conditions co-occur more often together than expected by chance. It does not prove that ME/CFS causes depression, depression causes ME/CFS, or that they share a single specific biological mechanism. Cross-sectional design means temporal relationships cannot be determined, and self-reported diagnoses without clinical confirmation may introduce diagnostic bias or misclassification.
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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