Can Community Social Cohesion Prevent Posttraumatic Stress Disorder in the Aftermath of a Disaster? A Natural Experiment From the 2011 Tohoku Earthquake and Tsunami

Abstract

In the aftermath of a disaster, the risk of posttraumatic stress disorder (PTSD) is high. We sought to examine whether the predisaster level of community social cohesion was associated with a lower risk of PTSD after the earthquake and tsunami in Tohoku, Japan, on March 11, 2011. The baseline for our natural experiment was established in a survey of older community-dwelling adults who lived 80 kilometers west of the epicenter 7 months before the earthquake and tsunami. A follow-up survey was conducted approximately 2.5 years after the disaster. We used a spatial Durbin model to examine the association of community-level social cohesion with the individual risk of PTSD. Among our analytic sample (n = 3,567), 11.4% of respondents reported severe PTSD symptoms. In the spatial Durbin model, individual- and community-level social cohesion before the disaster were significantly associated with lower risks of PTSD symptoms (odds ratio = 0.87, 95% confidence interval: 0.77, 0.98 and odds ratio = 0.75, 95% confidence interval: 0.63, 0.90, respectively), even after adjustment for depression symptoms at baseline and experiences during the disaster (including loss of loved ones, housing damage, and interruption of access to health care). Community-level social cohesion strengthens the resilience of community residents in the aftermath of a disaster.

Social capital and cognitive decline in the aftermath of a natural disaster: a natural experiment from the 2011 Great East Japan Earthquake and Tsunami

“…Studies have also suggested that social capital is protectively associated with depression and posttraumatic stress disorder following disasters 4 . Our study extends the evidence by showing that social capital can buffer the impact of disaster experiences on cognitive decline.…”

“…For improving disaster resilience and protecting the health of older adults, it is increasingly recognized that preserving social connections in the community – also referred to as “social capital” – serves as a critical ingredient 4,5 . According to Aldrich (2012) 6 , communities endowed with higher stocks of social capital – i.e.…”

Reducing depressive symptoms after the Great East Japan Earthquake in older survivors through group exercise participation and regular walking: a prospective observational study

“…The participant flow chart is shown in figure 1. 29 Study participants were selected for the Iwanuma project based on the following inclusion criteria: respondents from the 2010 and 2013 surveys who had no limitations in activities of daily living (ADL) (ie, they could independently walk, bathe and visit the toilet) at the baseline survey in 2010.…”

Increased risk of dementia in the aftermath of the 2011 Great East Japan Earthquake and Tsunami

“…Our primary outcome was dementia diagnosis ascertained by in-home assessment during the follow-up period. Among our analytic sample (n = 3,566), 38.0% reported losing relatives or friends in the disaster, and 58.9% reported property damage. Fixed-effects regression indicated that major housing damage and home destroyed were associated with cognitive decline: regression coefficient for levels of dementia symptoms = 0.12, 95% confidence interval (CI): 0.01 to 0.23 and coefficient = 0.29, 95% CI: 0.17 to 0.40, respectively.…”