Conduct disorder, antisocial personality disorder and substance use disorders in schizophrenia and major affective disorders.

OBJECTIVE: To examine the relationships between childhood conduct disorder (CD), antisocial personality disorder (ASPD) and substance use disorders (substance abuse or substance dependence) in psychiatric patients with severe mental illness.
METHOD: Substance use-related problems on screening instruments, lifetime and recent prevalence of substance use disorders, and family history of substance use disorder were evaluated in four groups of 293 patients with mainly schizophrenia-spectrum and major affective disorders: No ASPD/CD, CD Only, Adult ASPD Only, Full ASPD.
RESULTS: Full ASPD was strongly related to all measures of substance use problems and disorders, as well as fathers' history of substance use disorder. The odds ratios for Full ASPD and substance use disorders ranged between 3.96 (lifetime cannabis use disorder) to 11.35 (recent cocaine use disorder). To a lesser extent, patients with CD Only or Adult ASPD Only were also at increased risk for having substance use disorders compared to the No ASPD/CD patients.
CONCLUSIONS: Childhood CD and adult ASPD represent significant risk factors for substance use disorders in patients with schizophrenia-spectrum and major affective disorders. Considering other research indicating that CD and ASPD have a higher prevalence in patients with severe mental illness, the present findings suggest that CD and ASPD could reflect a common factor that independently increases patients' vulnerability to both psychiatric and substance use disorders.