The Interaction of Active Drug Use and Depression on Antiretroviral Adherence

Abstract

The widespread use of highly active antiretroviral therapy (HAART) to treat HIV has resulted in great health benefits. However, suboptimal HAART adherence is associated with poor HIV treatment outcomes and the development of drug resistant virus. While active substance use and depression are both associated with HAART non-adherence, little is known about their interaction. The goals of this study were to examine associations between adherence, active drug use and depression, and to explore the interaction between active drug use and depression on adherence among drug users in Methadone Maintenance Treatment (MMT). Bivariate analyses examined the main effects of all substances and depression with adherence. Then, logistic regressions tested their independent effects on adherence. Finally, the interaction between each substance and depression was assessed. Post hoc analyses of significant interactions were conducted. In total, 51% reported use of any illicit drugs in the past thirty days. In bivariate analysis, any illicit drug use (OR [95% CI]: 0.39 [0.16-0.95], p = 0.040) and marijuana use (OR [95% CI]: 0.026 [0.10-0.70], p = 0.002) were associated with non-adherence. In regression analysis, models comprised of any illicit drug use and depression (R² = 0.07, chi² = 6.81, p = 0.033), cocaine use and depression (R² = 0.06, chi² = 6.60, p = 0.037), and marijuana use and depression (R² = 0.13, chi² = 13.60, p = 0.003) were significant. Interactions were found between any illicit drug use and depression (OR [95% CI]: 1.23 [1.06-1.44], p = 0.007), and between any use of "downers" and depression (OR [95% CI]: 1.30 [1.03-1.64], p = 0.030). Any illicit drug use and use of "downers" were associated with non-adherence among participants with low depression, but not associated with adherence among participants with high depression. There was no additive effect between illicit drug use and depression on adherence, as fewer participants who reported drug use alone (59%), depression alone (61%), or drug use and depression (62%) achieved adherence than those who reported neither (96%), but achieved the same level of adherence as those who reported both (chi² = 11.66, p = 0.009). In this sample of methadone maintained drug users, drug use was associated with non-adherence, and depression contributed to non-adherence. Despite attending MMT, continued drug use suggests an unmet need for treatment interventions. Drug use and depression should be targeted in adherence improving interventions. Longitudinal studies should be conducted to further examine the interaction of drug use and depression. Clinicians should take into account that drug users choose their drug of abuse for specific psychological reasons.