Objectives: To investigate the association between sleeping problems in adolescence and subsequent hospital admission for self-harm (SH).
Design: Prospective cohort study, linking health survey information on sleep problems to hospital-based patient records.
Setting: Residents of Nord-Trøndelag County, Norway, aged 13-19 years in 1995-97.
Patients or participants: 10,202 adolescents were invited to participate in the Young-HUNT study; 8,983 (88%) completed the health survey.
Measurements and results: 10% of participants reported difficulties initiating sleep, 4% reported early morning wakening. Ninety-eight participants (27% male) were hospitalized following SH over a mean 12 years follow-up. Difficulties initiating sleep/early morning wakening were associated with increased risk of SH (HR 2.11, 95% CI 1.29-3.46, sex- and age-adjusted) compared with no problems, yet coexistent symptoms of combined anxiety/depression explained most of the association with sleep problems (fully adjusted HR 1.19, 95% CI 0.66-2.16). The HR of combined difficulties initiating sleep/early morning wakening differed in those with and without anxiety/depression at baseline (P interaction = 0.03); among those without caseness symptoms of anxiety/depression it was 5.58 (95% CI 2.02-15.40), while in those with caseness symptoms of anxiety/ depression it was 0.82 (95% CI 0.19-3.44).
Conclusions: Sleep problems are common among Norwegian adolescents. The strong association between sleep problems and subsequent hospitalization for self-harm could mainly be related to coexistent symptoms of anxiety and depression. Prevention of adolescent sleep problems, anxiety and depression should be targeted when seeking to reduce and prevent self-harm.
Keywords: Difficulties initiating sleep; adolescents; anxiety and depression; cohort study; early morning wakening; self-harm.