A standardised multimodal school-based suicide prevention program for adolescents: Protocol for a cluster randomized controlled trial in China.

Suicide among adolescents is a critical global public health concern and ranks among the top three causes of death for this age group. Globally, more than 700,000 people die by suicide each year across all age groups. In China, this issue has also drawn growing societal attention, particularly in high-resource metropolitan areas, where mental health has become a priority on the educational agenda. Consequently, schools in these regions have pioneered diverse mental health promotion projects and established various psychological education curricula, creating a unique opportunity to implement and rigorously evaluate a standardized multimodal school-based suicide prevention program within an already active implementation environment. Capitalizing on this existing infrastructure, this study aims to conduct a cluster-randomized controlled trial evaluating a multimodal school-based suicide prevention program that integrates a structured student curriculum with teacher gatekeeper training. Schools will be randomized 1:1 to the intervention arm or the usual-practice control arm. All Grade 7 students from participating schools will be invited to participate. Student-reported suicide risk will be assessed at baseline (T0), post-intervention (T1), and 6-month follow-up (T2). The primary outcome is student suicide risk at the 6-month follow-up. Primary statistical inference will adhere to the intention-to-treat principle, utilizing generalized linear mixed-effects models. The study commenced in September 2025, with participant recruitment scheduled to run from early November 2025 to mid-December 2025. We hypothesize that the multimodal program will demonstrate beneficial effects on adolescent psychological outcomes compared with usual practice. Findings from this study will provide the empirical evidence for a dual-target, culturally grounded school-based suicide prevention approach in China, and inform the development of scalable suicide prevention strategies globally.