Long-Term Mental Health Trajectories After Great East Japan Earthquake: A Systematic Review

Introduction: The Great East Japan Earthquake (GEJE) of 2011, compounded by the ensuing tsunami and Fukushima nuclear disaster, had profound impacts on the affected populations. While the immediate psychological consequences of the disaster have been well-documented, less is known about the long-term mental health trajectories of survivors. This systematic review aims to synthesize existing longitudinal studies to provide a comprehensive overview of long-term mental health outcomes following the GEJE in Japan. Methods: This review was conducted following PRISMA guidelines. Using predefined inclusion criteria, a comprehensive search across PubMed, Web of Science, and APA PsycINFO was performed to identify studies assessing symptoms of PTSD, depression, and psychological distress among GEJE survivors with multi-wave follow-up data, with at least one time point being one year or longer post-exposure. Results: A search conducted in July 2024 screened 1183 references and identified 24 longitudinal studies, spanning from seven months before to 140 months after the GEJE. The included studies varied in sample characteristics, measurement tools, cut-off criteria, and follow-up time points, making direct comparisons challenging. Across most studies, PTSD, depression, and distress showed an initial peak in symptoms following the disaster, which gradually declined over time. In some studies, PTSD symptoms appeared to start higher and show a sharper decline compared to depression or distress. Additionally, variations were observed among different subgroups, including junior high school children and long-term evacuees, who tended to exhibit higher or more sustained levels of mental health challenges. Conclusion: The systematic review highlights that the GEJE has had enduring effects on survivors’ mental health. While PTSD symptoms tend to decline significantly over time, symptoms of psychological distress and depression also decrease, albeit at a slower rate. Long-term mental health care should be provided, especially for vulnerable subgroups, to mitigate the disaster’s lasting psychological impacts.