Mental health is one of the most important issues for disaster survivors, and many studies have reported higher rates of mental health problems after disasters (e.g., hurricanes and tsunamis) [2– 5]. In Japan, mental health problems have been a matter of great concern after disasters, such as the Hanshin Awaji Earthquake in 1995 that killed more than 5,500 people [6] and the NiigataChuetsu Earthquake in 2004 that forced the evacuation of 103, 000 residents [7]. However, the Great East Japan Earthquake wreaked enormous damage, surpassing that of previous disasters.