Non-suicidal self-harm among adolescents with substantiated childhood maltreatment: Findings from the Norwegian Triple-S Study

Abstract

Background

Childhood maltreatment (CM) is a well-established risk factor for psychological distress and self-harm in adolescence. However, few studies have examined how specific types of maltreatment, multivictimization, and familial factors jointly contribute to non-suicidal self-harm (NSSH).

Aims

To investigate the prevalence and correlates of NSSH among Norwegian adolescents with substantiated experiences of CM, including associations with specific subtypes, multivictimization, ethnicity, and family history of self-harm.

Method

We analysed self-reported data from 308 adolescents (aged 12–18 years; 81.2 % girls) with substantiated maltreatment experiences who attended a national residential facility for children and young people with experience of abuse and violence between 2016 and 2024. Self-harm behaviours were assessed using validated items adapted from the CASE study. Associations were examined using Poisson regression, adjusting for age and sex.

Results

Overall, 52.8 % reported a history of self-harm, with 35.8 % reporting ≥10 episodes. Girls were more likely to report NSSH than boys (59.3 % vs. 25.0 %), although boys reported an earlier age of onset. One in six participants reported familial self-harm or suicide attempts. Self-harm prevalence increased with the number of maltreatment types experienced, from 42.4 % (one type) to 61.0 % (four or more types). All CM types were associated with high rates of NSSH. Ethnic Norwegian adolescents had higher self-harm prevalence than their immigrant-background peers.

Conclusions

NSSH is alarmingly common among adolescents exposed to CM, particularly among girls and those who have experienced multivictimization. These findings highlight the need for early, developmentally appropriate, and family-inclusive intervention strategies.