BACKGROUND:

Major studies of psychiatric comorbidity in opioid abusers reported rates of comorbidity that far exceeded general population estimates. These studies were published more than a decade ago and reported on few women and few substance use diagnoses.

METHODS:

Psychiatric and substance use comorbidity was assessed in 716 opioid abusers seeking methadone maintenance. Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition diagnostic assessment was conducted 1 month after admission. Rates of psychiatric and substance use disorder were compared by gender, and associations were assessed between psychiatric comorbidity and dimensional indexes of substance use severity, psychosocial impairment, and personality traits.

RESULTS:

Psychiatric comorbidity was documented in 47% of the sample (47% women and 48% men). Antisocial personality disorder (25.1%) and major depression (15.8%) were the most common diagnoses. Patients had at least 2 substance use diagnoses, most often opioid and cocaine dependence. Demographics, substance use history, and personality variables discriminated between patients with vs without comorbidity. Psychiatric comorbidity also was associated with a more severe substance use disorder.

CONCLUSIONS:

Psychiatric comorbidity, especially personality and mood disorder, was common in men and women. The positive associations between psychiatric comorbidity and severity of substance use and other psychosocial problems were most consistent among those with antisocial personality.