[Service system models for adolescent mental health in different institutional contexts and their implications for China].

Based on health systems and multi-level governance theories, an analytical framework of "policy elements-implementation mechanisms-governance outcomes" was developed, covering seven dimensions: legal safeguards, financial commitment, service networks, human resources, digital/remote support, inter-sectoral collaboration, and early prevention and intervention. Structured coding was applied to Brazil, Australia, Germany, and the United States. The coding evidence was limited to laws, strategies, budgets, and project documents issued by governments or government-authorized agencies; materials from authoritative institutions such as the World Health Organization, the Organization for Economic Co-operation and Development, the Australian Institute of Health and Welfare, and the U.S. National Center for Education Statistics; and peer-reviewed studies. The analysis revealed that Brazil developed a public health-oriented community integration pathway through the Unified Health System, the Psychosocial Care Network, and the School Health Program. However, dedicated child and adolescent mental health resources were unevenly distributed. In Australia, relatively clear institutional linkages were established among its national strategy, public funding, the headspace youth service network, eheadspace digital support, and the Be You school mental health capacity-building initiative. In Germany, a collaborative model combining social insurance and youth welfare was formed based on Social Code BookⅧ, statutory health insurance, and a common self-governance mechanism, yet a unified, nationally coordinated school-centered youth mental health service network has still not been established. In the United States, schools have become a critical entry point for mental health services, with service provision being jointly driven by federal grants, advancing wellness and resiliency in education project, school-based mental health service subsidies, and the 988 suicide & crisis lifeline. However, insufficient funding and workforce shortages remain major constraints. Consequently, an effective adolescent mental health service system is not a replication of any single institutional model but rather the result of aligning policy elements, implementa-tion mechanisms, and institutional contexts. For China, leveraging strong government coordination and an extensive education system, a hybrid service system should be constructed, in which schools serve as key entry points, county-level and community services provide support, the medical system offers specialized backup, and digital tools play an auxiliary role. The continuity and equity of the system should be enhanced through mandated collaboration, sustainable financing, a tiered workforce, and outcome-oriented evaluation.