Comorbid personality disorders and substance use disorders of mentally ill homicide offenders: a structured clinical study on dual and triple diagnoses.

Abstract

Comorbid substance use disorders (SUDs) increase the risk of homicide by persons with major mental disorders (MMDs). However, there are no published data from clinical interviews or lifetime objective documents on the prevalence of lifetime personality disorder (PD) or SUD among a comprehensive sample of mentally ill homicide offenders. Therefore, a nationally representative sample of men with MMD (n = 90) who had committed or attempted homicide was assessed using the research version of the Structured Clinical Interview for DSM-IV Axis I and Axis II Disorders. Lifetime documents, records, and questionnaires from persons who knew the subjects since childhood were used. Seventy-eight percent of the mentally ill homicide offenders were diagnosed with schizophrenia, 17 percent with schizoaffective disorder, and 5 percent with other psychosis. A lifetime SUD was detected in 74 percent and alcohol use disorder in 72 percent. PD accounted for 51 percent, in 47 percent as antisocial personality disorder (APD). All subjects diagnosed with PD had SUD. Only 25 percent of the subjects had neither SUD nor PD. Among persons with dual diagnoses (MMD and SUD), about two-thirds had PD or APD. These results indicated that there were two-thirds major diagnostic categories of psychotic homicide offenders: about one-half had triple diagnosis (APD + SUD + MMD), one-quarter had "pure" dual diagnosis (SUD + MMD), and one-quarter had "pure" MMD. The fourth possible category, "APD + MMD but no SUD," was not found. The prevention of severe violence by persons with MMD necessitates effective treatments for those with dual diagnosis who also have a history of APD.