Psychiatric severity and HIV-risk sexual behaviors among persons with substance use disorders

The relationship between mental illness and human-immunodeficiency virus (HIV)-risk sexual behavior among persons with substance use disorders is not well-established because of differences in assessing psychiatric factors (types, symptoms, severity), substance use (diagnosis, survey responses, past substance use), and HIV-risk sexual behaviors (individual measures, combination of sex/drug use risk behaviors) across studies. This study utilized a more global and dimensional aspect of psychiatric issues (problem severity) to examine the relationship with HIV-risk sexual behaviors and substance use among persons with substance use disorders.

Participants included 224 men and 46 women, with a mean age of 40.4 years (SD = 9.5). The most common substances were heroin/opiates, with 41.4% reporting use of these substances (n = 110), while 27.8% reported using cocaine (n = 74) and 12.8% reported using alcohol (n = 34). Of all participants, 39 (14.4%) were identified as having high psychiatric severity (defined using the psychiatric severity score from the Addiction Severity Index), which was used as an indication of probable comorbid psychiatric and substance use disorders. Among these participants likely to have comorbid disorders, hierarchical linear regression was conducted to examine HIV-risk sexual behaviors (number of partners and unprotected sexual behaviors in the past 30 days) in relation to psychiatric severity, substance use, and gender.

Gender (women) and psychiatric severity (higher) were significantly related to greater HIV-risk sexual behaviors. After entering gender and substance use into the regression model, psychiatric severity accounted for another 21.9% of the variance in number of partners and 14.1% of the variance in unprotected sexual behaviors. Overall, the models accounted for 55.5% and 15.6% of the variance, respectively. A significant interaction was found for number of partners (but not frequency of unprotected behavior), such that those higher in psychiatric severity and higher in substance use had a greater number of sexual partners. The model including this interaction term accounted for 63.4% of the variance in number of partners.

Findings suggest psychiatric severity is an underlying risk factor for HIV-risk sexual behavior among persons with substance use disorders who have various psychiatric comorbidities.