Resilience Factors Affecting Long-Term Trajectories of Depressive Symptoms in the Aftermath of the Great East Japan Earthquake and Tsunami Among Older Adults

ObjectivesWe examined long-term trajectories of depressive symptoms among older adults following exposure to the 2011 Great East Japan Earthquake and Tsunami. We further characterized the pre- and post-disaster social relationship factors that predicted membership in each trajectory group.MethodsData from 4 time points (including pre-disaster data) were used to analyze the depression trajectories of 2,033 survivors through a group-based trajectory model. Multinomial logistic analysis was used to investigate the social relationship factors (i.e., social interactions with neighbors, social support, social participation, and social cohesion) that predicted membership to each trajectory group.ResultsFive distinct trajectories of depressive symptoms were identified; stably not depressed (12.4%), increased after the disaster (14.2%), decreased after the disaster (8.8%), persistent mild depressive symptoms (28.1%), and persistent severe depressive symptoms (36.5%). Compared to those who were stably not depressed, those who experienced an increase in symptoms were more likely to experience housing damage and not to participate in social activities. Compared to those who were stably mildly depressed, those who experienced a decrease in symptoms had higher pre-disaster social interactions with neighbors as well as higher post-disaster social support. Adults with persistent severe symptoms were physically, psychologically, and socially vulnerable preceding the disaster.DiscussionThe study revealed the heterogeneity of older adults experiencing depressive symptoms in the wake of major disaster. Those who experienced increased symptoms after the disaster showed a chronic rather than temporary rise, while those with pre-disaster depressive symptoms showed sustained symptoms regardless of disaster-related trauma.