Adolescent non-suicidal self-injury: a cross-national study of community samples from Italy, the Netherlands and the United States.

This study examined rates and correlates of non-suicidal self-injury (NSSI) across three non-clinical adolescent samples from different countries. Surveys were administered to 1862 adolescents (M(age)=15.69, S.D.=0.87) from Italy (n=827), the Netherlands (n=675), and United States (n=360), including measures of NSSI, substance use, internal (i.e., depressive symptoms, loneliness), and interpersonal factors (i.e., peer victimization, peer preference). After controlling for socio-demographic differences, similar prevalence of NSSI was found across the three samples, with approximately 24% of the adolescents reporting at least one NSSI episode within the last year. Multivariate logistic regressions showed that adolescents' victimization and higher levels of depressive symptoms and family-related loneliness were associated concurrently with NSSI comparably in all three samples. However, multi-group analyses indicated that the association between NSSI and substance use varied significantly across samples, indicating that NSSI related more strongly to substance use (i.e., cigarette smoking and frequent marijuana use) in the sample from the United States rather than the samples from the Netherlands and Italy. Findings provide evidence of NSSI and suggest high similarities in rates and correlates across samples from different countries. Future research should further explore NSSI cross-nationally.