Prevalence and predictors of insomnia and sleep medication use in a large tri-service US military sample.

OBJECTIVE: The presence of insomnia in the general military population is not well known. This study aimed to determine the prevalence of probable clinical insomnia and identify factors leading to new-onset insomnia and/or sleep medication use in a large military population. DESIGN: Cross-sectional and longitudinal analyses of a prospective cohort study. PARTICIPANTS: A tri-service US military and veteran cohort (sample range 99,383-137,114). MEASUREMENTS: Participants were surveyed in 2013 (Time 1 [T1]) and 2016 (Time 2 [T2]) using the clinically validated Insomnia Severity Index. The prevalence of insomnia and sleep medication use was quantified at both times. Multivariable models identified military factors associated with new-onset insomnia and/or sleep medication use while adjusting for covariates. RESULTS: The prevalence of insomnia at T1 and T2 was 16.3% and 11.2%, respectively. New-onset insomnia at T2 was reported by 6.0% of participants screening negative at T1; risk factors included Army service, combat deployment experience, and separation from military service. The prevalence of sleep medication use at T1 and T2 was 23.1% and 25.1%, respectively. Sleep medication use at T2 was newly-reported by 17.1% of participants not reporting sleep medication use at T1; risk factors included number of deployments and having a healthcare occupation. CONCLUSIONS: The prevalence of probable clinical insomnia in this large general military population is within the range of previous reports in military and civilian populations. Certain military factors that predict new-onset insomnia and/or sleep medication use should be considered when designing and implementing sleep interventions in military populations.