Associations between family and peer self-harm exposure and self-harm behaviors among young adults: Findings from the SSNE study

Self-harm among young adults is a significant public health concern influenced by psychosocial, demographic, and environmental factors. Although prior research has emphasized social contagion and mental health risk, less is known about how exposure to self-harm within family and peer networks relates to variation in self-harm behaviors. This study examined cross-sectional associations among social exposure to self-harm, mental health indicators, and sociodemographic characteristics using data from the Spatial Social Network and Environmental Exposure (SSNE) study. Data from 2422 young adults aged 18–29 were analyzed; 969 participants with complete data were included in multivariate regression models. Descriptive statistics, bivariate correlations, and multiple linear regression analyses assessed associations between social exposure, mental health variables, sociodemographic factors, and lifetime self-harm behavior scores. Overall, 37.9% of participants reported a history of self-harm, and 51.9% reported a diagnosed mental health condition. The mean self-harm score was 11.03 (SD = 9.20). In adjusted models, family and peer exposure to self-harm, diagnosed mental health conditions, and higher psychological distress were associated with lower self-harm scores, whereas sexual minority status and minority status were associated with higher scores. Findings highlight complex, non-causal associations between social exposure, mental health, and self-harm behaviors. These results underscore the importance of context-sensitive assessment and intervention planning following self-harm or exposure. • Family and peer self-harm history were negatively associated with self-harm behavior. • Mental health diagnosis and distress showed inverse relationships with self-harm. • Sexual minority and combined minority status predicted higher self-harm tendencies. • Findings reveal social and mental health complexities in youth self-harm behavior. • Interventions should target resilience and inclusive mental health engagement.