Swanink, C M, Vercoulen, J H, Bleijenberg, G et al. · Journal of internal medicine · 1995 · DOI
This study compared 88 people with ME/CFS to 77 healthy controls matched by age, sex, and location. Researchers tested blood work, checked for infections, and used questionnaires to measure fatigue, depression, and how much the illness affected daily life. Standard blood tests came back normal in ME/CFS patients, but they reported significantly more fatigue, depression, and difficulty with daily activities than healthy controls.
This study demonstrates that ME/CFS cannot be diagnosed or distinguished from health using standard blood tests, emphasizing that ME/CFS is not explained by detectable infections or routine laboratory abnormalities. It clarifies that the psychological burden (depression, reduced function) observed in ME/CFS patients reflects the severity of the illness itself rather than indicating a primary psychiatric cause.
This study does not prove that ME/CFS is primarily psychiatric or psychological in origin, despite findings of depression and functional impairment—these appear to be consequences of symptom severity rather than causes. It does not establish that no biological markers exist; it only shows that standard clinical laboratory panels do not discriminate between patients and controls. The study cannot determine cause-and-effect relationships between psychological measures and illness severity.
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 →
Spotted an error in this entry? Report it →