Introduction: Sleep disturbances have been linked to suicidality among adolescents. However due to small sample sizes in previous studies and the low incidence of suicide attempt, large and longitudinal studies are needed to conduct meaningful adjusted analysis. We aimed to estimate whether experiencing sleep disturbances were associated with subsequently higher risk of suicidal ideation and suicide attempts in adolescents.
Method: 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. Odds ratios with corresponding 95% confidence intervals were estimated using multivariable multinomial logistic regressions adjusting for sex, sociodemographic characteristics, and parental psychiatric diagnoses, and procedures of inverse probability weighting were applied.
Results: This study included 28,251 participants of whom 32.0% had experienced suicidal ideations while 3.3% had attempted suicide. Adolescents who, at age 11, were sleeping <8 hours had higher risk of suicidal ideation (aOR= 1.66, 95% CI: 1.32-2.07) and suicide attempt (aOR= 3.71, 95% CI: 2.56-5.39) compared to adolescents sleeping ?9 hours. Similar risk estimates were observed among adolescents going to sleep at 11:00 p.m. or later for suicidal ideation (aOR= 1.58, 95% CI: 1.28-1.95) and suicide attempt (aOR= 3.34, 95% CI: 2.30-4.86) compared to adolescents going to sleep at 09:00 p.m. or earlier. Having frequent nightmares were associated with suicidal ideation (aOR= 1.39, 95% CI: 1.30-1.49) and suicide attempt (aOR= 2.10, 95% CI: 1.80-2.45) compared to adolescents who rarely or never experienced nightmares. Dose-response relationships were found with respect to more difficulties falling asleep as well as higher number of reported sleep disturbances for suicidality. Persistent difficulties falling asleep also had higher risk of suicidal ideation (aOR= 2.93, 95% CI: 2.65-3.23) and suicide attempt (aOR= 6.69, 95% CI: 5.37-8.33) compared to those not reporting difficulties falling asleep. These associations were still significant after adjustment for youth psychiatric diagnoses and mental health variables.
Conclusion: Sleep disturbances is associated with later suicidality during teenage years. Attention towards sleep hygiene and observation of mental health in adolescents struggling with sleep is warranted.