Are Personality Dimensions Associated with Sleep Length in a Large Nationally Representative Sample?

Objectives: The purpose of this hypothesis-generating study was to determine whether personality domains and specific personality traits are uniquely associated with sleep duration using data obtained from the National Comorbidity Survey (NCS).

Methods: Using trained interviewers, we administered to the 5877 noninstitutionalized adults living in the United States the Composite International Diagnostic Interview (World Health Organization. Composite International Diagnostic Interview. Geneva, Switzerland: WHO, 1990) to assess for any DSM-III-R psychiatric diagnoses, and they completed self-report measures of personality and sleep. This was a secondary data analysis using information from a large existing public use data set (NCS-part II). The NCS-part II was an epidemiologic survey based on a stratified multistage area probability method with a response rate of 82.4%.

Results: Using a multivariate logistic regression technique, we found significant and positive associations between short sleep (defined as <or=6 hours of sleep per 24-hour period) and self-criticism (odds ratio [OR] = 1.36), the presence of a medical condition (OR = 1.35), neuroticism (OR = 1.30), and the use of sedating medication in the past 12 months (OR = 1.26). Significant and positive associations were found for long sleep (defined as >or=9 hours per 24 hour period) and a diagnosis of dysthymia (OR = 1.52), the use of a sedating medication in the past 12 months (OR = 1.52), emotional reliance on another person (OR = 1.37), employment status (OR = 1.31), and marital status (OR = 1.20).

Conclusions: Findings suggest that personality, even after controlling for psychiatric and medical conditions, is associated with sleep length and may be an additional factor to consider when assessing any individual patient.