Excessive daytime sleepiness mediates the relationship between insomnia symptoms and suicidal behavior in adolescents

Study Objectives Insomnia symptoms, excessive daytime sleepiness (EDS), and suicidal behavior are prevalent among adolescents. Growing studies have shown that both insomnia symptoms and EDS are associated with suicidal behavior. However, little is known about the pathways between insomnia symptoms, EDS, and suicidal behavior. This study aimed to examine the longitudinal mediating effect of EDS on insomnia-suicidal behavior link in a large sample of Chinese adolescents. Methods Participants were 7072 adolescents (Mean age = 14.58 years, 50.0% males) who were surveyed at baseline and were followed up 1 year later in the Shandong Adolescent Behavior and Health Cohort study. A self-administered questionnaire was used to measure insomnia symptoms, daytime sleepiness, sleep duration, social jetlag, suicidal behavior, and adolescent and family demographics. Results The prevalence of insomnia symptoms and EDS at baseline were 14.3% and 21.1%, respectively. Adolescents with insomnia symptoms or EDS at baseline were more likely to report suicidal behavior at 1-year follow-up compared to adolescents without insomnia symptoms or EDS. Path analyses showed that EDS played a significant mediation role between insomnia symptoms and suicidal behavior (including any suicidal behavior, suicidal thought, suicide plan, and suicide attempt) before and after adjusting for adolescent and family factors, sleep duration, social jetlag, and prior suicidal behavior. Conclusion Insomnia symptoms and EDS were associated with increased risk of subsequent suicidal behavior. The association between insomnia symptoms and suicidal behavior was mediated by EDS. These findings highlight the importance of assessment and treatment of insomnia and daytime sleepiness for suicide prevention in adolescents.