Social Jetlag and Other Aspects of Sleep Are Linked to Non-Suicidal Self-Injury Among College Students.

INTRODUCTION: Disrupted sleep is associated with non-suicidal self-injury (NSSI) in young adults, but many specific features of sleep continuity and timing have yet to be examined. Additionally, the psychological mechanisms linking sleep to NSSI are unclear. The present study evaluated 14 sleep variables as classifiers of lifetime or recent NSSI and examined potential confounding and mediating factors. METHODS: A sample of 885 college students provided measures of sleep continuity (e.g., duration, timing, fragmentation), nightmares, insomnia, and perceived sleep control. Lifetime and past 3-month NSSI were measured using a self-report version of the Columbia Suicide Severity Ratings Scale. Bidirectional stepwise regression identified significant sleep classifiers and subsequent models examined their associations with NSSI after adjusting for covariates and through potential psychological mediators. RESULTS: Only absolute social jetlag was associated with recent NSSI, even after adjusting for covariates, such that each additional hour difference between weekday and weekend sleep schedules was associated with a 17% greater risk of recent NSSI. Nightmares, weekend sleep efficiency, and perceived sleep control were associated with lifetime NSSI, although only weekend sleep efficiency remained associated after adjusting for covariates. Bootstrap mediations identified negative urgency as a partial mediator for recent and lifetime NSSI, and lack of premeditation and perceived burdensomeness as partial mediators for lifetime NSSI. CONCLUSIONS: The timing and consistency of young adults' sleep schedules may be of greater importance to NSSI among college students than insomnia or insufficient sleep. Future studies of sleep and NSSI should include these measures as potential risk factors. HIGHLIGHTSDifferences between weekday/weekend sleep timing are linked to recent NSSI.Negative urgency partially mediates poor sleep on recent and lifetime NSSI.Sleep shares a multifaceted relationship with NSSI risk in college students.