Dispositional Optimism and Disaster Resilience: A natural experiment from the 2011 Great East Japan Earthquake and Tsunami.

Abstract

Dispositional optimism - the general belief that good things will happen - is considered a key asset for the preservation of mental health after a traumatic life event. However, it has been hypothesized that in extreme situations such as major disasters where positive expectations cannot overcome the grim reality on the ground, being optimistic might be a disadvantage. To test this mismatch hypothesis, this study explores whether higher pre-disaster dispositional optimism is associated with higher posttraumatic stress (PTS) and depressive symptoms among individuals who experienced the 2011 Great East Japan Earthquake and Tsunami. Information on optimism was collected from community-dwelling residents aged ≥65 years seven months before the 2011 Earthquake/Tsunami in Iwanuma, a Japanese city located 80-km from the epicenter. Data on disaster-related personal experiences (e.g., loss of relatives or friends/housing damage), as well as depressive and PTS symptoms, were collected during a follow-up survey in 2013, 2.5 years after the earthquake and tsunami. Multiple logistic regression models were utilized to evaluate the associations between disaster experiences, optimism, and depressive/PTS symptoms among 962 participants. Higher pre-disaster dispositional optimism was associated with lower odds of developing depressive symptoms (OR=0.78, 95% CI: 0.65 to 0.95) and PTS symptoms (OR=0.83, 95% CI: 0.69 to 0.99) after the earthquake. Contrary to the mismatch hypothesis, high dispositional optimism buffered the adverse impact of housing damage on depressive symptoms (interaction term coefficient=-0.63, p=0.0431), but not on PTS symptoms. In contrast to the mismatch hypothesis, the results suggest that dispositional optimism is a resilience resource among survivors of a disaster.