Chronic insomnia and military separation: a retrospective matched cohort and nested case-control study of U.S. active component service members, 2014-2023.

This study characterized chronic insomnia disorder, utilizing data from the Defense Medical Surveillance System, to identify incident cases among U.S. active component service members from 2014 through 2023. A total of 126,733 service members met the case definition and were matched 1-to-1 with service members without chronic insomnia by sex, age, and time in service. Chronic insomnia was associated with increased probability of early separation from military service and frequently co-occurred with conditions that limit military readiness. Kaplan-Meier analysis showed diverging retention curves approximately 20 months following diagnosis, after which chronic insomnia cases had lower probability of continued active component service. A nested case-control analysis of 55,679 individuals with chronic insomnia found that early separation was associated with service branch, age, sex, race and ethnicity, marital status, rank, occupation, co-occurring diagnoses, and behavioral therapy or pharmacotherapy within 365 days of diagnosis. Behavioral therapy or pharmacotherapy within 365 days of diagnosis was more common among those who separated early. Continued attention to case surveillance, early identification, and timely evidence-based treatment may help mitigate the impacts of insomnia on service outcomes. Service members with chronic insomnia face increased risk of early separation from service in the military. Early separation was more common among service members who had received behavioral therapy or pharmacotherapy within the first year after diagnosis. A high burden of co-occurring conditions was identified, including behavioral health disorders, traumatic brain injury, and chronic pain.