TUESDAY, Sept. 2, 2025 (HealthDay News) -- Sleep problems in early teens are associated with future self-harm, according to a study published online Aug. 4 in the Journal of Child Psychology and Psychiatry.Michaela Pawley, Ph.D., from the University of Warwick in the United Kingdom, and colleagues examined the cross-sectional and long-term effects of several sleep phenotypes on self-harm and whether decision-making moderated this relationship. The analysis included 10,477 participants in the Millennium Cohort Study with sleep variables measured when individuals were approximately 9 months, 14 years, and 17 years of age.The researchers found that shorter sleep duration on school days (adjusted odds ratio [aOR], 0.875), longer sleep onset latency (aOR, 1.005), and more frequent night awakenings (aOR, 1.140) were significantly associated with self-harm at age 14 years, even when controlling for demographic and clinical covariates. Over time, shorter sleep duration on school days (aOR, 0.926), longer sleep onset latency (aOR, 1.003), and more frequent night awakenings (aOR, 1.090) also had a direct prospective effect on self-harm at age 17 years, when adjusting for demographic and clinical factors. Rational decision-making, measured using the Cambridge Gambling Task, did not significantly contribute to this relationship."While this is clearly an unfavorable relationship, one positive from this research is that sleep is a modifiable risk factor -- we can actually do something about it," Pawley said in a statement. "If the link between sleep and self-harm holds true and with well-placed interventions in schools and homes, there is a lot we can do to turn the tide."Abstract/Full Text.Sign up for our weekly HealthDay newsletter