Background: On 11 March 2011, the Great East Japan Earthquake followed by a gigantic tsunami hit the Pacific coast of Northeast Japan (Tohoku) and damaged Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Plant, causing a radiation hazard in the entire Fukushima Prefecture. The radiation dose exposed either externally and internally in Fukushima residents have been evaluated to be low so far and it is hardly believed that they may have any direct radiation risk on physical condition. The purpose of this report is, therefore, to describe results of a mental health and lifestyle survey intended to facilitate adequate care for residents who are at a higher risk of developing mental health problems after the complicated accident.
Participants and methods: The target population of this survey is the residents of evacuation zones including Hirono Town, Naraha Town, Tomioka Town, Kawauchi Village, Okuma Town, Futaba Town, Namie Town, Katsurao Village, Minamisoma City, Tamura City, Yamakiya district of Kawamata Town, and Iitate Village. The targeted population was 210,189 in fiscal year 2011 (FY2011) and 211,615 in fiscal year 2012 (FY2012). Questionnaires have been mailed since January 2012, and subsequently, January 2013, 10 and 22 months after the disaster. Among of them, children 63.4%, adults 40.7% for FY2011, and children 41.0%, adults 29.7% for FY2012 responded to the questionnaires mailed.
Results: Sociodemographic data showed that many evacuee households were separated after the disaster and had to move several times. K6 was used in this survey to estimate general mental health. The proportion (14.6% in FY2011 and 11.9% inFY2012) of adults who scored above the K6 cut-off (≥13) for general mental health was higher than usual, indicating severe mental health problems among evacuees. The proportion (21.6% in FY2011 and 18.3% inFY2012) of adults who scored above the cut-off (≥44) of PTSD checklist (PCL), reflecting traumatic symptoms, was almost equal to that of the workers after the 9.11 World Trade Center attacks. These results also indicate the presence of severe traumatic problems among evacuees. The proportions of children (4-6 years old) and children of primary school age (6-12 years old) who scored above the cut-off (≥16) of Strengths and Difficulties Questionnaire (SDQ) reflecting the mental health status in children, 24.4% and 22.0% in the survey of FY2011, were double the usual state respectively, whereas 16.6% in children of 4-6 years old and 15.8% in children of 6-12 years old in FY2012 were 1.5 times. These findings also disclosed the presence of severe mental difficulties in children, with relative improvement year by year.
Conclusion: As revealed by the present mental health survey, the earthquake and tsunami followed by the nuclear accident caused psychological distress among residents in Fukushima prefecture. Continuous survey and mental care programs are required.