Associations between time in bed and suicidal thoughts, plans and attempts in Korean adolescents

OBJECTIVES To examine the hypothesis that respondents with any of three specific sleep patterns would have a higher likelihood of suicidality than those without reports of these patterns in Korean adolescents. SETTING Data from the 2011-2013 Korea Youth Risk Behavior Web-based Survey were used. PARTICIPANTS 191,642 subjects were included. The survey's target population was students in grades 7 through 12 in South Korea. INDEPENDENT VARIABLE Sleep time. PRIMARY AND SECONDARY OUTCOME MEASURES Suicidal thoughts, plans and attempts. RESULTS The odds of suicidal thoughts in subjects with very short or long time in bed were 1.487-fold higher (95% CI 1.219 to 1.815) or 0.611-fold lower (95% CI 0.460 to 0.811), respectively, than for subjects with 7 h/day in bed; the odds were similar for suicidal plans. The odds of suicidal thoughts in subjects with early or late awakening times were 1.231-fold higher (95% CI 1.050 to 1.442) or 1.528-fold lower (95% CI 1.000 to 2.334), respectively, than for subjects with 7 h/day in bed; these odds were lower for suicidal plans and attempts. The odds of suicidal thoughts in subjects with early bedtime were 1.748-fold higher (95% CI 1.302 to 2.346), the odds of suicidal plans in people with an early bedtime were 2.494-fold higher (95% CI 1.671 to 3.722) and the odds of suicide attempts in subjects with late bedtime were 1.313-fold higher (95% CI 1.005 to 1.716) than for subjects with a bedtime of 23:00. CONCLUSIONS The sleep-related time is associated with suicide-related behaviours in Korean adolescents. Multilateral approaches are needed to identify the greatest risk factors for suicidal behaviours.