Long-term mental health trajectories after the Great East Japan Earthquake: a systematic review

<b>Background:</b> 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.<b>Objective:</b> This systematic review aims to synthesize existing longitudinal studies to provide a comprehensive overview of long-term mental health outcomes following the GEJE.<b>Methods:</b> This review was conducted in accordance with PRISMA guidelines. Using predefined inclusion criteria, a comprehensive search across PubMed, Web of Science, APA PsycINFO, and Ichushi was performed from July 2024 to May 2025. We examined studies assessing post-traumatic stress symptoms (PTSS), depression, and psychological distress among GEJE survivors with multi-wave follow-up data where at least one assessment took place 1 year or longer after the disaster.<b>Results:</b> We screened 1,719 references and identified 30 reports of 27 longitudinal studies encompassing over 197,351 participants. The included studies varied in sample characteristics, measurement tools, cut-off criteria, and follow-up time points, making direct comparisons challenging. Across most studies, outcomes for PTSS, depression, and psychological distress showed an initial peak in symptoms following the disaster, which gradually declined over time. In some studies, PTSS appeared to show a sharper decline compared to depression or psychological distress. Variations were observed among different subgroups, including long-term evacuees, women, and older individuals, who tended to exhibit higher or more sustained levels of symptoms.<b>Conclusions:</b> This systematic review highlights that the GEJE has had enduring impacts on survivors' mental health. While PTSS tends to decline substantially over time, psychological distress and depression also decrease, albeit in a slower manner. Long-term mental health care should be provided, especially for vulnerable subgroups, to mitigate the disaster's lasting psychological impacts.