Relationship between substance use and socio-behavioral drivers of poor ART adherence among young people with HIV in Zambia

Despite improved access to antiretroviral therapy (ART) in Zambia, adherence among young people with HIV (YPHIV) remains suboptimal, compromising treatment effectiveness. YPHIV face unique developmental and socio-behavioral challenges including HIV-related stigma, depression and substance use, which further undermine consistent ART adherence. Alcohol and drug use impair cognitive and emotional functioning, increasing the likelihood of disrupted medication routines. This study applied the Hierarchical Model of Medication Adherence (HMMA) to examine how individual, social and structural factors influence ART adherence among YPHIV in Zambia. A qualitative descriptive design was employed using six focus group discussions (FGDs) with 48 purposively selected participants aged 18-24 years, all reporting <80% adherence and recent substance use. Data were audio-recorded, transcribed verbatim and thematically analyzed. HIV-related stigma, mental health distress and negative healthcare experiences were key drivers of substance use. Substance use impaired adherence by causing forgetfulness and other factors. Depression and emotional exhaustion also emerged as major contributors to substance use and poor adherence. The study offers novel, context-specific insights into the multilevel drivers of poor adherence among Zambian youth aged 18-24. Findings highlight the need for youth-centred interventions that address stigma, mental health and substance use to improve ART adherence and health outcomes.