Psychopathy traits explain variance shared between features of substance use disorders and violence

Background: There is a substantial research literature on identifying risk and protective factors for violence perpetration. Substance use disorders have long been identified as constituting a significant predictor of violent behaviour. Psychopathy traits have also been similarly recognised, but inter-relationships between psychopathy traits, features of substance use disorders and violence have been little explored. Aims: To determine the degree to which shared variance between substance dependence symptoms and violence, as indicated by criminal charges for violent offences, among jailed men can be explained by psychopathy traits. Methods: Features of dependence on substances in three drug classes (alcohol, cannabis and cocaine) were assessed in a sample of 682 men in a county jail awaiting trial on criminal charges, many for violent offences. Statistical comparisons of zero-order and partial correlations tested whether accounting for psychopathy total and facet scores, assessed by the Psychopathy Checklist-Revised (PCL-R), affected associations between substance dependence symptoms and violent charges. Results: Total PCL-R scores accounted for a significant proportion of the shared variance between the history of criminal charges for violence offences and lifetime substance dependence symptoms in all three drug classes. At the facet level, controlling for ratings on the interpersonal and modified antisocial facets reduced the association between criminal charges for violent offences and symptoms of cocaine dependence; controlling for ratings on a modified antisocial facet also attenuated links between alcohol and cannabis dependence symptoms and history of charges for violent offences. Conclusion: These findings build on the sparse literature to date on the role of psychopathy traits on relationships between features of substance use disorders and violence. Given that the observed connection between substance dependence symptoms and charges for violent offences is partly accounted for by individual differences in psychopathy traits, and it follows that effective treatment for those traits may be useful, perhaps essential to reducing links between features of some substance use disorders and violent offending.