The Six-Year Mental Health Time Course of Disaster Workers in the Flooding of Joso City, Japan

Introduction: On September 10th, 2015, the Kanto-Tohoku heavy rain caused the banks of the Kinu River in Joso City to collapse over approximately 200m, flooding one-third of the city. As a result, 4,258 people were evacuated. Local government officers, while being evacuees, have been supporting the affected citizens for years. To evaluate their mental health deterioration, five follow-up surveys and staff follow-ups from 2015 to 2020 were conducted. Methods: The Department of Disaster and Community Psychiatry, University of Tsukuba, conducted a survey on mental health and mental disorders after the disaster among Joso City employees from 2015 to 2020. The questionnaires used were the Kessler Distress Scale (K6), Peritraumatic Distress Index (PDI), Impact of Event Scale-Revised (IESR), Center for Epidemiologic Studies Depression Scale (CESD), and Resilience Scale-14 (RS14). The study was approved by the Ethics Committee of the University of Tsukuba Hospital. Results: 559 City Hall workers joined the survey, scores in stress-related scales showed a decreasing trend by years with an average of 6.2 (1st yr), 4.2 (2nd yr), 4.2 (3rd yr), 4.1(4th yr), and 4.2 (5th yr) in K6. 15.1, 14.6, 14.1, 14, 2, and 13.5 in PDI, and 12.9, 11.0, 10.1, 8.9, and 9.94 in IESR. On the other hand, the depression and resilience scale showed a stable trend, with an average of 9.0, 7.8, 8.6, 8.9, and 9.1 in CESD, and 61.4, 62.8, 62.5, 62.7, and 61.7 in RS-14. Conclusion: It was found that the number of people with stress-related problems was. The K6, PDI, and IESR scores were on a decrease. There was not much change in the CESD or RS14 scores. Results suggest that stress-related mental health improves as recovery progresses over time, and the psychological impacts of adapting to the effects of the flood do not change.