A protocol for population-level data linkage to investigate patterns of service use and health care needs of young people from Victoria Australia experiencing mental ill-health

Introduction: Mental disorders are a leading cause of disease burden among those aged 10-24 years. Mental disorders are diverse, complex and multifaceted, and co-morbidity is common. However, fragmentation across multiple services and sectors (health, mental health and human services) results in gaps in service provision. In the context of ongoing mental health service reform in Australia. Comprehensive evaluation of the whole care system is critical for shaping policy and ensuring efficient allocation of resources. In this paper we describe the protocol for a population-based data linkage study that involves evaluating patterns of health, mental health, and human service use among young people in Victoria, Australia with the goal of identifying subgroups experiencing unmet mental health needs.Methods and analysis: Our primary cohort is youth aged 12-25 years during the time period January 2018 to November 2023. Data for individuals aged 5-11 and 26-53 during this period will also be included, to allow for examination of early years factors and an older adult comparison group. The data sources and data linkage methodology are described. Traditional statistical methods coupled with contemporary machine learning and natural language processing techniques will be used.Study outcomes: Ongoing consultation and engagement with young people and key stakeholders will inform interpretation, dissemination and translation of findings. We will provide a comprehensive evaluation of the clinical characteristics of young people, their broader health and human service use behaviour and typical pathways through care, that could not be gleaned from examining datasets in isolation. Findings will inform ongoing mental health service reform that will lead to improvements in healthcare delivery and outcomes for Victorian youth.