Five-year post-disaster mental changes: Mothers and children living in low-dose contaminated Fukushima regions.

It has been almost 10 years since the accident at Tokyo Electric Power Co., Inc.'s Fukushima Daiichi Nuclear Power Plant in March 2011. This study elucidates changes in the mental states of mothers and children residing in low-dose radiation contaminated regions within Fukushima Prefecture over a five-year period after the Fukushima Daiichi accident. From 2011 to 2015, questionnaire surveys assessing psychological symptoms, including posttraumatic stress disorder-related responses, depressive responses, and stress responses, and radiation protection behaviors were conducted with 18,741 mothers of children aged four, 18, and 42 months. Mothers' and children's psychological symptoms and mothers' radiation protection behaviors were highest in 2011, immediately following the nuclear accident, but decreased over time. However, even in 2015, psychological symptoms and radiation protection behaviors were higher for children and mothers within Fukushima Prefecture than for those in a control group living in regions outside the area, which were minimally affected by the accident. The results suggest that the psychological effects in mothers and children living in low-dose radiation contaminated areas continued for at least five years after the accident. Furthermore, psychological effects in children born after the incident were likely to have been triggered by the parental behavior of mothers who were negatively affected by anxiety and stress. This finding raises concerns regarding the accident's long-lasting psychological effects in mothers and children living in low-contamination regions.