The Psychological Impact of the Great East Japan Earthquake on Japan Ground Self-Defense Force Personnel: A Three-Wave, One-Year Longitudinal Study

Abstract

Objective: Approximately 70,000 Japan Ground Self-Defense Force (JGSDF) personnel were dispatched in the wake of the 2011 Great East Japan Earthquake and the tsunami and nuclear disaster that followed. This study was conducted to evaluate the mental health of the JGSDF personnel and the correlates. Methods: Data collected from 56,753 participants at three time points (one, six, and 12 months after mission completion) were analyzed. Those who scored 25 or more points on the Impact of Events Scale–Revised (IES-R) and the Kessler Psychological Distress Scale (K10) were allocated into the high posttraumatic stress response (high-PTSR) group, and the high general psychological distress (high-GPD) group, respectively. Results: The multiple logistic regression analysis identified the following factors as the significant risk factor related to high-PTSR or high-GPD status, with odds ratios of 2.0 or higher: deployment length of three or more months, being personally affected by the disaster, and being overworked continuously for three or more months after mission completion. No significant association was observed for duties with radiation exposure risk. Conclusions: Our findings suggest that disaster workers may be able to conduct disaster relief activities more safely with mission-related considerations of shorter deployment length and recognizing the effects on personnel personally affected by the disaster, in addition to avoiding overworking personnel after mission completion.