Mental Health and ART Adherence in a Multisite International Study: The Mediating Roles of Social Support and Substance Use in People with HIV.

ART adherence, essential to preventing disease progression for people living with HIV (PLHIV), remains challenged by factors like poor mental health condition, insufficient social support, and substance use. This study investigates the roles of social support and substance use as mediators in the relationship between mental health and antiretroviral therapy (ART) adherence among PLHIV in a multisite, international context. Cross-sectional data from N = 1598 PLHIV across eight countries were analyzed using parallel mediation analyses in R. Results indicated that both social support and substance use independently mediated the relationship between mental health and ART adherence. Hallucinogens mediated the mental health-adherence link. Cocaine, Amphetamine-type stimulants, inhalants, and opioids directly influenced adherence but did not mediate this relationship. In contrast, no significant effects were observed for tobacco, alcohol, cannabis or sedatives. This large-scale, nurse-led, international study offers critical insights into the roles of social support and substance use as psychosocial influencers in the cascade of care for PLHIV. Clinical implications include prioritizing educative, preventative, and harm-reductive approaches to specific substances that impact ART adherence. Findings may also inform interventions that emphasize strengthening social support to improve adherence in ART and care while addressing substance use as a barrier to care and well-being.