There is a critical gap in access to mental health promotion, prevention and support among youth worldwide, especially in low and middle-income countries like Vietnam. The Y-PRIME Study aims to respond to this gap by co-designing with Vietnamese youth a mobile app that delivers life skills and self-management skills intervention to promote mental well-being in grade 10 Vietnamese students. Working with the Vietnam Youth Advisory Council (V-YAC) to adapt and co-design the intervention and app ensure that the intervention will be culturally appropriate and relevant to Vietnamese youth. The goal of the current phase is to test this intervention with grade 10 students across three provinces (Hanoi, Thai Binh, and Hung Yen) to assess:

1. Whether the app helps to improve mental well-being and resilience among youth in Vietnam and helps to reduce factors that might increase the risk of poor mental well-being, like stress related to school and other pressures
2. Whether the app can be delivered in Vietnamese schools
3. Whether Vietnamese youth and school staff think the app is appropriate and appealing for youth in order to scale-up the model across the country

The control group (meaning they do not have access to the app-based intervention) will complete the outcome survey at baseline, 6 months, and 12 months. After 12 months, they will gain access to the intervention app (at the same time as the experimental group) but no more data will be collected. The intervention group will use the app at their own pace for 1 year while completing the same survey at baseline, 6 months, and 12 months marks. Afterwards, students and school health staff will be invited to a focus group discussion to talk about their experience using the app.

Between 10-20% of the world's children and youth experience mental health problems; suicide is among the five leading causes of mortality among adolescents. Despite this, youth-oriented mental health promotion, prevention, and support are severely limited, especially in low and middle-income countries (LMICs). Vietnam has a population of 97 million people, 70% of whom are under the age of 35 years. Like many LMICs, Vietnam has extremely limited mental health promotion, prevention and care availability for youth. Life skills-based programs, delivered at a population level via schools, are an evidence-based approach that have the potential to improve mental health, resilience, and well-being among youth in low- resource settings. Digital health approaches including interventions delivered via mobile apps are also increasingly recognized as an effective, acceptable, and accessible approach to promoting youth mental health and wellness and warrant more research, particularly within LMICs.

The Youth Promotion of Resilience Involving Mental E-health (Y-PRIME) study will respond to the gap in the availability of evidence-based interventions to promote mental health, well-being, and resilience for youth in Vietnam. In Phase 1 of the study, the investigators engaged key stakeholders in the adaptation and co-design of an evidence-based mobile app intervention to be used among secondary school students. In this current study, the mobile app will be tested among secondary school students in three provinces (Hanoi, Thai Binh, Hung Yen) in Vietnam.

The investigators hypothesize that a youth-informed intervention adapted for the Vietnamese context and delivered via an app will lead to positive implementation outcomes among youth and within the implementation environment. The investigators also posit that it will lead to improved mental health, well-being, resilience, and risk-factor-related outcomes among Vietnamese youth.

Phase 2 will consist of a hybrid type 2 (where both implementation and clinical outcome measures are assessed), quasi-experimental, sequenced pre-post implementation design. The intervention takes a population-level approach to enhancing life skills and self-management skills that may be beneficial to all youth regardless of their mental health status. As this is a universal intervention, all students in grade 10 of participating secondary schools will be eligible to participate regardless of mental health and well-being status, as measured by standardized outcome measures. Control and intervention cohorts will be enrolled in each school in successive years. The control cohort will be recruited first and will be given the outcome assessments survey at baseline, 6 months, and 12 months marks. The control group will have access to the app after they have completed their final outcome assessment survey, but they will no longer provide outcome data and any in-app usage data (e.g. number and frequency of logins) which will be collected automatically by the app, will be excluded from the final analysis. The intervention cohort, recruited the year after the control cohort, will have full access to the app and will complete the same outcome measures at baseline, 6 and 12 months. Their app-usage data will be included in the final analysis.

The app-based intervention, co-designed with the V-YAC, aims to introduce life skills and self-management skills to promote general mental well-being and resilience among Vietnamese youth. With this app, youth users will have a fun and safe space to learn and practice six life skills areas (Problem-solving, Social Media and Well-being, Communication and Interpersonal Skills, Realistic Thinking, Coping with Emotions and Stress, and Goal Setting). Lessons (in the form of short texts) and activities (ex. multiple choice activities, blank worksheets, reflection questions) were adapted from evidence-based interventions developed in other contexts and were adapted in partnership with the V-YAC to ensure the skills and examples are culturally appropriate to the Vietnamese youth context. Youth users are free to explore the app at their own pace. Gamification features will also allow youth users to collect points in the app for completing each lesson, activity, or challenge (aimed to help encourage youth users to continue to practice skills after completing lessons). They then can use points to unlock and buy different accessories and backgrounds for their avatar (which is a gender neutral cartoon astronaut). Additionally, our app will include a mood check-in feature (where youth users can log and track their moods over time), guided breathing exercises, and a journaling feature.

Focus group discussions will be conducted with 6 - 8 participants at each school at the 12-month mark for each cohort to explore their experiences with the app, focusing on usability, appropriateness, and acceptability of app use. Semi-structured interviews with SHS, head teachers, and principals in each school will also be conducted to understand factors affecting implementation and potential scale-up of this intervention.

Inclusion Criteria:

• Enrolled in grade 10 of participating secondary schools
• Have access to a smartphone
• Provided informed assent to participate
• Parent of participant provided informed consent for their child to participate

Exclusion Criteria:

• Not in grade 10
• Not enrolled in participating secondary schools
• Not have access to a smartphone
• Not provided assent
• Parent did not provide consent