Overview

• Using the UK Millennium Cohort, a longitudinal analysis followed more than 10,000 adolescents who reported on sleep and self-harm at ages 14 and 17.
• Shorter sleep on school nights, longer time to fall asleep, and more frequent night awakenings at 14 were each associated with self-harm at 14 and at 17.
• The associations held after adjusting for age, sex, socioeconomic status, previous self-harm, self-esteem and depressive symptoms, with sleep the only factor consistently significant over time.
• The hypothesized explanation that poor sleep raises risk via poorer decision-making was not supported, leaving the causal pathway unclear.
• The authors highlight school and home-based sleep interventions as practical prevention options, with the study published Aug. 20 in the Journal of Child Psychology and Psychiatry.