Adolescent Predictors of Deliberate Self-Harm Thoughts and Behavior Among Young Adults: A Longitudinal Cross-National Study

Purpose: This study builds upon and extends previous longitudinal research on deliberate self-harm (DSH) among youth by investigating which risk and protective factors during adolescence predict DSH thoughts and behavior in young adulthood. Methods: Self-report data came from 1,945 participants recruited as state-representative cohorts from Washington State and Victoria, Australia. Participants completed surveys in seventh grade (average age 13 years), as they transitioned through eighth and ninth grades and online at age 25 years. Retention of the original sample at age 25 years was 88%. A range of risk and protective factors in adolescence for DSH thoughts and behavior in young adulthood were examined using multivariable analyses. Results: Across the sample, 9.55% (n = 162) and 2.83% (n = 48) of young adult participants reported DSH thoughts and behaviors, respectively. In the combined risk-protective factor multivariable model for young adulthood DSH thoughts, depressive symptoms in adolescence (adjusted odds ratio [AOR] = 1.05; confidence interval [CI] = 1.00-1.09) increased risk, while higher levels of adolescent adaptive coping strategies (AOR = 0.46; CI = 0.28-0.74), higher levels of adolescent community rewards for prosocial behavior (AOR = 0.73; CI = 0.57-0.93), and living in Washington State decreased risk. In the final multivariable model for DSH behavior in young adulthood, less positive family management strategies during adolescence remained the only significant predictor (AOR = 1.90; CI = 1.01-3.60). Discussion: DSH prevention and intervention programs should not only focus on managing depression and building/enhancing family connections and support but also promote resilience through efforts to promote adaptive coping and connections to adults within one's community who recognize and reward prosocial behavior. (C) 2023 Society for Adolescent Health and Medicine. All rights reserved.