Sleep disturbances in early adolescents and risk of later suicidality: A national prospective cohort study.

Introduction: Sleep disturbances have been linked to later suicidality among adolescents. This study assessed the associations between sleep disturbances experienced at age 11 and the subsequent occurrence of suicide thoughts and suicide attempt measured at age 18. Methods: Self-reported data on sleep disturbances measured at age 11 was obtained from the Danish National Birth Cohort and linked to information on suicidality at age 18 based on self-reports and register-based data on hospital contacts for suicide attempt. Relative risk ratios(RRR) with corresponding 95 % confidence intervals were estimated using multivariable multinomial logistic regressions adjusting for sex, sociodemographic characteristics, psychiatric history, and child risk behaviors and procedures of inverse probability weighting were applied . Results: A total of 28,251 participants were included, of whom 8894 (32.0 %) reported suicide thoughts and 743 (3.3 %) attempted suicide at age 18. Adolescents who at age 11 reported sleeping <8 hours per night had elevated risk of suicide thoughts (aRRR, 1.7; 95 % CI, 1.3-2.1) and suicide attempt (aRRR, 3.7; 95 % CI, 2.6-5.4) when compared with those sleeping ≥9 hours. Going to bed after 10:30PM versus before 9:00PM on weekdays was associated with higher risks of suicide thoughts (aRRR, 1.6; 95 % CI, 1.3-2.0) and suicide attempt (aRRR, 3.3; 95 % CI, 2.3-4.9). Dose-response relationships documented that experiencing difficulties falling asleep more often was associated with higher risks of suicide thoughts and suicide attempts. Adjusting for child psychiatric co-morbidity attenuated results, however associations still showed statistical significance. Conclusion: Sleep disturbances were associated with later suicidality among adolescents. Significant associations suggested that adequate hours of sleep and earlier bedtimes might protect against suicidality in children and adolescents.