Positive psychological intervention to reduce HIV acquisition risk with men who use stimulants: protocol for a randomised controlled trial

Introduction A resurgent methamphetamine epidemic is a major driver of HIV incidence in the USA. Although daily oral pre-exposure prophylaxis (PrEP) is highly effective for preventing HIV acquisition, its effectiveness depends on achieving and maintaining prevention-effective adherence (ie, four or more doses per week). Digital health interventions offer a scalable method to extend the reach of behavioural approaches to HIV prevention, but evidence of their efficacy in improving objectively measured adherence remains limited. Addressing this gap is critical to maximising the clinical and public health benefits of PrEP. Methods and analysis From 26 January 2022 through 17 January 2025, this single-blind, parallel-group randomised controlled trial (RCT) enrolled 239 men taking PrEP who reported problematic stimulant use and who resided in California or Florida. Participants were randomised to receive five individually delivered telehealth sessions of a positive psychological intervention (n=119) or an attention-control condition (n=120), both delivered alongside remote contingency management for directly observed PrEP doses using the Spotlight mobile health application. Participants received US$20 per session and up to US$360 for uploading videos of at least four PrEP doses per week over 3 months. Follow-up assessments at 3, 6 and 12 months included surveys and dried blood spot specimens to quantify tenofovir diphosphate (TFV-DP). The primary outcome is biobehavioural HIV acquisition risk, defined as any recent condomless anal sex in the absence of TFV-DP concentrations consistent with prevention-effective adherence. Ethics and dissemination This RCT was approved by the University of Miami Institutional Review Board and registered prior to initiation of enrolment. Analyses of primary and secondary outcomes using intent-to-treat principles will be conducted after the completion of TFV-DP assays in June 2026, with results disseminated shortly thereafter through peer-reviewed publications. Registration This RCT was registered on www.clinicaltrials.gov ( NCT04899024 ) prior to launching enrolment.