Understanding the Age of Onset for Self-Harm in Youth: Insights from a Scoping Review

A scoping review out of Ireland published in Child and Adolescent Psychiatry and Mental Health found that earlier onset of self-harm predicts greater persistence and severity of future self-injurious behavior. Most included studies place onset in early adolescence, with modal ages concentrated in a narrow mid-adolescent window. Clinically, earlier-starting self-harm denotes a higher-risk trajectory and requires urgent attention in pediatric practice.

The age of onset was most commonly reported between 12 and 14 years across included studies (modal values clustered at 12–13 years, with study-level ranges roughly spanning 9–18 years). A minority of studies reported mean onsets near 9–10 years and some later peaks around 15–16 years. The 12–14-year window represents a pragmatic target for routine screening in early adolescence and for school-based surveillance.

Studies varied in how they defined self-harm (intentionality; suicidal versus non-suicidal), and that heterogeneity affects onset estimates. The review highlighted cultural and environmental moderators such as school climate, family adversity, and differential access to services as influences on observed distributions. Samples drawn from younger community cohorts tended to report earlier means, whereas clinical and service-attending cohorts often showed later detected onset.