Background The relationship between substance use disorders and criminal activity is strong, and one that is not easily resolved in the criminal justice system. A better understanding of personality traits among substance misusers who commit offences could support better treatment efforts. Aims The aim of this study is to explore associations between the psychopathology of people addicted to substances who have also committed crimes. Methods We recruited 263 substance‐dependent individuals (80% male, 20% female) from a cohort of people attending regional community services in Italy. They all completed an extensive evaluation of their current mental health and personality traits. Their official criminal records were obtained, and the psychopathology of those who had a criminal record compared with those who did not. Results The criminal group was more likely to perceive the external world as hostile and to consider others as responsible for their own problems and difficulties; in addition, substance‐dependent individuals with criminal records showed more personality traits within the psychopathy range and fewer in the dependent personality range than the substance abusers who had never committed crimes. Conclusions These findings allow us to hypothesise that substance abusers who also have criminal convictions may have a specific personality profile. If further research were to confirm this, then it could have important implications for identifying people for particular treatment pathways and developing more effective treatments. Copyright © 2016 John Wiley & Sons, Ltd.