Mood and substance use disorders are prevalent among incarcerated youths. Much research has focused on externalizing symptoms of juvenile males with a criminal record, and little is known about introverted personality types. Schizoid personality traits lie on the introversion personality dimension and have specific characteristics that represent potentially maladaptive intra- and interpersonal styles. A latent variable approach explored pathways between childhood trauma, schizoid personality traits, and substance problems among 1,029 juvenile males who committed an offense. Trauma, schizoid personality traits, and social support were specified as predictors, and substance problems represented the outcome of a structural equation model. The model tested whether or not social support was a mediator for the association between schizoid personality and substance problems. Moreover, I was interested in the association between trauma, schizoid personality, and substance problems.

I found that childhood trauma was significantly and positively related to schizoid personality traits, and that it had an indirect, positive effect on substance problems. Specifically, schizoid personality mediated the relationship between trauma and substance problems. Trauma appeared to increase substance problems through the pathway it shared with schizoid personality traits, yet not through the pathway of social support. Results show that schizoid personality had a positive, significant association with substance problems, while social support was not significantly related to the outcome. There was no evidence that social support mediated the relation of schizoid personality and substance problems. Hence, a lack of social support did not explain why individuals higher on schizoid traits used alcohol or drugs in problematic ways. The study calls for intervention models that incorporate personality assessments for enhancing services to fit with interpersonal styles of clients.

Screening for substance use behaviors is not sufficient when treating youths who committed crimes; assessing trauma history and personality style are important elements for treatment planning. Social support as a strength may not buffer the effects of trauma and schizoid personality traits, so that alternative or additional strengths should be assessed and incorporated into the treatment of adolescents who struggle with antisocial behaviors such as criminal activity and substance use.