Reframing Suicide as a Multifactorial Phenomenon: Toward a One Health Approach in Public Mental Health

Japan has one of the highest suicide mortality rates among the G7 countries, with suicide being the leading cause of death among young people—a serious public health concern. Suicide and related mental health conditions are complex phenomenon that cannot be explained by a single factor; in addition to demographic variables, mental disorders, and socioeconomic status, recent studies suggest the involvement of various environmental and biological factors, such as the gut microbiota, relationships with companion animals, and climate change. These findings highlight the need to move beyond traditional psychiatric and sociological perspectives and to consider a broader One Health approach that includes environmental and life sciences. Our research team has conducted forensic analyses of suicide death cases investigated by medical examiners, focusing on associations between demographic characteristics, psychiatric consultation history, and methods of suicide. We have also examined systemic challenges in Japan’s suicide surveillance framework, including the divergence in populations covered by different data sources and the limited geographic coverage of forensic investigations into suicide deaths. We advocate for the importance of interdisciplinary research aimed at understanding the reality of suicide and implementing effective preventive interventions. Building an integrated registry that incorporates insights from diverse fields and adopting One Health perspective may serve as a foundation for future suicide prevention policy.