David, A, Pelosi, A, McDonald, E et al. · BMJ (Clinical research ed.) · 1990 · DOI
This study asked over 600 people visiting their doctor about fatigue and what they thought caused it. About 1 in 10 people reported severe fatigue lasting a month or longer. People blamed fatigue on different causes—some physical (like infections), some psychological or social (like stress or family responsibilities)—and the study found that fatigue itself looked similar whether it lasted a short time or persisted longer.
This study demonstrates that disabling fatigue is common in general practice and often attributed to multiple causes—a finding relevant to ME/CFS because it shows how difficult it is to distinguish ME/CFS from other fatigue conditions in primary care settings and highlights the need for clearer diagnostic criteria.
This study does not establish causation between the attributed causes and fatigue; it only shows what patients believed caused their symptoms. The cross-sectional design cannot determine whether physical illness causes fatigue or vice versa. Most importantly, the study's minimal ME/CFS case identification suggests its brief questionnaire was not designed to detect ME/CFS accurately, limiting conclusions about ME/CFS prevalence or characteristics.
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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