Bailes, Sally, Libman, Eva, Baltzan, Marc et al. · Journal of psychosomatic research · 2006 · DOI
Doctors and patients often use the words 'sleepiness' and 'fatigue' interchangeably, but they actually describe different experiences. This study created two short, separate questionnaires—one to measure sleepiness (the urge to sleep) and one to measure fatigue (overall exhaustion)—by pulling items from existing popular fatigue and sleepiness scales. Testing these new scales on people with ME/CFS, narcolepsy, and healthy controls showed they measure distinct conditions that may respond to different treatments.
ME/CFS is often characterized by severe fatigue, yet clinicians may conflate this with sleepiness or sleep disorders. This study provides evidence-based tools to distinguish true fatigue from sleepiness, enabling more accurate diagnosis and targeted treatment. For ME/CFS patients specifically, differentiating fatigue from sleep-related symptoms could improve clinical management and reduce misdiagnosis.
This study does not establish prevalence of sleepiness versus fatigue in ME/CFS populations, nor does it determine which treatment interventions work best for each symptom type. The small ME/CFS sample (n=19) limits generalizability, and the cross-sectional design cannot establish whether these scales predict treatment outcomes or long-term disease course.
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 →