Mental health and substance use in the scale-up of HIV prevention

The past several years have witnessed dramatic advances in the potential for effective biomedical HIV prevention interventions. Recent landmark clinical trials, such as CAPRISA 004 and iPrEx, have shown that vaginal microbicides and oral preexposure prophylaxis (PrEP) can reduce the likelihood of HIV infection. Additionally, the results of HIV Prevention Trials Network (HPTN) 052 showed that early initiation of antiretroviral therapy (ART) could also function as a potential biomedical HIV prevention intervention. Nonetheless, many other trials of microbicides and PrEP failed to show a decrease in HIV incidence. Across these trials, it has been hypothesized that poor levels of treatment adherence accounted for the ineffectiveness of the interventions. It is well known that numerous mental health and substance use issues impact adherence to ART, and it is likely that adherence to PrEP and microbicides is similarly affected by these intertwined psychosocial problems. In this chapter, we discuss the impact of mental health and substance use on adherence, HIV transmission risk behavior, PrEP, microbicides, and ART as a secondary prevention strategy. Specifically, we examine how psychosocial syndemics, stigma, risk compensation, intimate partner violence, and the use of various substances (such as alcohol, cocaine, club drugs, methamphetamines) have been important factors in HIV treatment and prevention research to date, and then we present current research that applies these findings to biomedical prevention efforts. Finally, we discuss future research directions for addressing mental health and substance use issues in biomedical prevention interventions.