The mortality rate in one area of a Miyagi Prefecture city in the 2011 Great East Japan Earthquake and tsunami was four times higher among elderly residents at a high risk of developing depression than among other seniors, a research team has found.
The team including researchers from Tohoku University investigated the health conditions and other information of 860 people aged 65 or older in the Tamaura district of Iwanuma, Miyagi Prefecture, in August 2010 -- seven months before the area was hit hard by the tsunami. The project is part of the "Japan Gerontological Evaluation Study," a large-scale survey of the country's elderly.
Of the subjects, 39 were found to have a serious risk of depression, five of whom died on the day of the tsunami -- a mortality rate of 12.8 percent, roughly four times higher than the 3 percent rate among subjects without depressive tendencies. Even when the residents' distance from the coastline was figured into the calculations, those vulnerable to depression still had a mortality rate 3.9 times higher than the others.
The researchers believe that dementia associated with depression impaired ability to recognize the need to evacuate and that a negative attitude that "even if I evacuate, it won't save me" lowered motivation to escape.
Every municipality is legally required to keep a list of people needing assistance to evacuate in an emergency, but these do not always include those with psychiatric disorders.
"There is a necessity for municipalities to also consider evacuation support for those who have a tendency toward depression," the team points out.