Adaptation of Project Yes+ to improve mental health and reduce HIV-related stigma among adolescent and young men who have sex with men living with HIV in Vietnam - In Vietnam, adolescent and young men vulnerable to HIV through sexual behaviors are among those most affected by the infection, with an HIV prevalence that quadrupled from 3% in 2011 to 13% in 2020. More than 20% of Vietnamese young men living with HIV had moderate-to-severe depression and anxiety symptoms. These youths experienced extensive stigma related to their HIV status and sexual behaviors. There is a dearth of youth-friendly mental health services in Vietnam where there is less than one psychiatrist per 100,000 people. Project YES+ is an intervention integrating two evidence-based interventions, Project YES! and Self-Help+ to improve mental health, stigma, and HIV outcomes among youth living with HIV in Zambia (5R01TW012411). Youth Engaging for Success (Project YES!) is an HIV clinic-based peer mentoring CDC-designated intervention that successfully decreased HIV self-stigma and increased viral suppression. Self-Help+ is a group-based lay-delivered program endorsed by WHO that effectively prevents the onset of mental disorders and reduces mental health symptoms in different cultures. We propose to adapt Project YES+ for adolescent and young men living with HIV in Vietnam to create To Hieu (I Understand) and to pilot test the adapted intervention. The specific aims are to (1) Adapt Project YES+ to create To Hieu to improve mental health and reduce internalized HIV stigma for adolescent and young men living with HIV in Vietnam and (2) Examine acceptability and feasibility of To Hieu among adolescent and young men living with HIV through a pilot randomized controlled trial. In Aim 1, the adaption will follow the 8-step ADAPT-ITT framework.38 We will conduct in-depth interviews with adolescent and young men living with HIV (N=20) to explore preferences for the core components and formats of To Hieu. We will hold a human-centered design workshop to engage adolescent and young men living with HIV in co-design activities to refine To Hieu. In Aim 2, we will recruit 80 adolescent and young men living with HIV with depression or anxiety symptoms at two HIV clinics in Hanoi, Vietnam and randomize them 1:1 into two arms. The intervention arm will receive To Hieu in 4 months, while the control arm will receive standard of care at the clinics. The RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) framework will guide the measurement of the outcomes. We will calculate participation rates of participants (Reach) at baseline. We will assess acceptability through the Client Satisfaction Questionnaire and feasibility through intervention attendance (Adoption) at 4 months. Depression, anxiety symptoms, internalized HIV and sexual stigma, ART adherence and viral suppression of participants will be evaluated at baseline, 4 months and compared between groups (preliminary Effectiveness). We will conduct exit interviews with participants, youth peer mentors and HIV providers (N=30) to explore acceptability, feasibility (Implementation) and sustainability (Maintenance) of To Hieu. This research will build local capacity and develop networks for collaborative research on mental health and stigma among adolescent and young men living with HIV between Vietnam and the US.