Individual and District-Level Determinants of Suicide: A Multilevel Case-Control Study in Seoul

Despite the implementation of various governmental mental health measures, suicide and mental illness remain critical public health challenges in South Korea. This study investigates the effects of individual and policy-level factors on suicide risk, aiming to provide empirical evidence to strengthen mental health interventions and suicide prevention strategies. A case-control study design was employed using three-level generalized linear mixed models to address the hierarchical panel structure of medical data. The analysis used nationally representative cohort data and metropolitan-level mental health statistics from 2017 to 2019, covering both individual and regional dimensions. A total of 1122 observations from 462 individuals were analyzed. Significant group differences were found in variables such as age, sex, disability status, insurance type, mental illness diagnosis, insurance premium quantile, registered patient status, and regional mental health budget. Multilevel modeling revealed that suicide risk increased over time and was notably higher among individuals with lower socioeconomic status and greater mental health vulnerability. Policy-related factors, particularly mental health budget allocations, were also significantly associated with suicide risk. The findings highlight the importance of identifying high-risk populations and implementing proactive, well-funded mental health policies to reduce suicide rates and improve mental health outcomes at both national and local levels.