Abstract
BACKGROUND: Multiple studies on adults have shown that depressive symptoms are the main contributing factors to suicide risk, and sleep symptoms are a major risk factor for depression. However, the associations between the three in adolescents have not been thoroughly studied. This study aims to examine the independent impact of sleep symptoms on suicide risk in adolescent depression and how this impact varies by age. METHODS: Adolescent and youth (ages 13-25) depressed patients were included based on a depression cohort. Sleep symptoms were assessed using the Athens Insomnia Scale (AIS) and the Epworth Sleepiness Scale (ESS), depressive symptoms using the 17-item Hamilton Depression Rating Scale (HAMD-17), and suicide risk using the Beck Scale for Suicide Ideation (BSSI). A mediation model was employed to distinguish direct associations from pathways mediated by depression, with age as a moderator. RESULTS: Among 744 depressed patients (mean age 18.31, 76.6% female), insomnia (β = 1.817, 95% CI: 1.505-2.129) and hypersomnia (β = 1.344, 95% CI: 1.073-1.615) had stronger direct associations on suicide risk than the depression-mediated pathway. Younger patients (≤15 years) exhibited the strongest insomnia-suicide associations (β = 1.950, 95% CI: 1.564-2.335), compared to age 16-18 (β = 1.662, 95% CI: 1.363-1.960) and age 19-25 (β = 1.278, 95% CI: 0.862-1.693). CONCLUSIONS: Sleep symptoms (insomnia and hypersomnia) directly elevate suicide risk, exerting a stronger influence than depressive symptoms. This association is most pronounced in younger patients, particularly early adolescents (≤15 years), highlighting the critical need for early, sleep-focused interventions in youth suicide prevention.