Excessive sleepiness and associated symptoms in the U.S. adult population: prevalence, correlates, and comorbidity

Objective: This study examined the prevalence, sociodemographic features, patterns of comorbidity, and impact on functional impairment of excessive sleepiness (Ex.S) and associated symptoms in a nationally representative sample of adults using the National Comorbidity Survey Replication (NCS-R) dataset. Methods: Participants ≥18 years (n = 5,962) were queried about their sleep using the Composite International Diagnostic Interview (CIDI). Specifically, respondents were questioned about feeling sleepy during the day and falling asleep in permissive situations, feelings of insufficient sleep despite adequate time in bed, and/or difficulty waking up. Those endorsing daytime sleepiness and at least one additional symptom were considered to have Ex.S plus associated symptoms. Associations between Ex.S plus associated symptoms and sociodemographics, Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) mental disorders, chronic physical conditions, and functional impairment were examined. Results: The prevalence of Ex.S plus associated symptoms in U.S. adults was 23.34% (standard error [SE] = 0.88) and significantly co-occurred with insomnia-related symptoms after adjusting for confounders (Odds ratio [OR] = 5.65; 95% confidence interval [CI] = 4.55-7.02). The presence of Ex.S and associated symptoms was more common in women, particularly younger women, those with lower family income, and the unemployed (all P<.001). After controlling for demographic characteristics and other confounders, Ex.S plus associated symptoms was associated with having a DSM-IV mental disorder (OR = 4.25; 95% CI = 3.53-5.10), a chronic physical condition (OR = 2.57; 95% CI = 1.94-3.42) and greater disability (P<.001). Conclusion: Ex. S with associated symptoms was common, frequently co-occurred with other mental and physical conditions, and was associated with substantial disability. Dissipation of some associations after controlling for insomnia-related symptoms indicated that physical-mental comorbidity and disability were greater among individuals with more pervasive sleep disturbances.