Long-term Trends in Mental Health Disorders After the 2011 Great East Japan Earthquake and Tsunami.

Posttraumatic stress symptoms (PTSS) and depressive symptoms are common among survivors of a major disaster, yet few longitudinal studies have documented their long-term persistence at the community level. To examine the trajectories of PTSS and depressive symptoms for as long as 5.5 years after the 2011 Great East Japan earthquake and tsunami. This cohort study used data from 2781 participants in 3 waves of the Iwanuma Study (2010, 2013, and 2016), a cohort of community-dwelling older adults (≥65 years in August 2010) in Iwanuma, Japan, who were directly affected by the 2011 disaster. The baseline assessment of mental health predated the disaster by 7 months, and survivors were followed up for 5.5 years after the disaster. Data analysis was performed from October 2019 to February 2020. The March 11, 2011, Great East Japan earthquake and tsunami. PTSS were measured by 9 questions on the Screening Questionnaire for Disaster Mental Health, while depressive symptoms were measured by 15 items on the Geriatric Depression Scale short form. The analytic samples for trajectories of PTSS and depressive symptoms included 2275 and 1735 respondents, respectively. In the study population at baseline, there were slightly more women (1262 of 2275 [55.5%] and 882 of 1735 [50.8%]), and most participants were aged 65 to 74 years (1533 [67.4%] and 1224 [70.5%]) and married (1664 [76.2%] and 1319 [77.7%]). Overall, there was a 13.6% (95% CI, 11.7%-15.6%) incidence of depression among individuals who did not have depression before the disaster, while a further 11.1% (95% CI, 9.8%-12.4%) reported PTSS after the disaster. By 5.5 years of follow-up, approximately half of the survivors with new depressive symptoms in 2013 (85 of 168 [50.6%]) and PTSS (147 of 253 [58.1%]) had recovered. The prevalence of depression in the community remained remarkably stable (between 504 participants [29.0%] and 506 participants [29.2%]) comparing predisaster and postdisaster data. In this study, mental illness symptoms persisted for more than 5 years among half of disaster survivors, but the community-wide prevalence of depression remained stable, suggesting that the community itself was resilient.