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The Royal College of Psychiatrists Improving the lives of people with mental illness

Nagasaki bomb causing mental distress more than 50 years on

Embargoed until 01 November 2011

New research suggests that people who were in the vicinity of the Nagasaki atomic bomb explosion – but not exposed to the radiation itself – are experiencing poor mental health more than half a century on.

The study, published in the November issue of the British Journal of Psychiatry, is believed to be the first to focus on the mental health effects of psychological exposure to nuclear disaster without exposure to radiation.

Researchers from the National Centre of Neurology and Psychiatry in Tokyo interviewed 347 people who had lived in Nagasaki since the atomic bomb explosion in 1945. Although they had all been in the vicinity of the explosion, they lived in areas that were officially recognised as being uncontaminated – where the radiation posed no significant risk to health. The participants were all asked to complete a General Health Questionnaire, which is used to identify if someone is at risk of mental disorder.

The researchers interviewed a further 277 people who had moved into the area from outside Nagasaki 5-15 years after the bombing. These people acted as the control group.

The researchers found that 75% of those who had been in the vicinity of the bomb were at high risk of mental disorder, based on their responses to the General Health Questionnaire, compared to 40% of the control group.

Three-quarters of the people who had been in the vicinity of the bomb still mistakenly believe that the flash of the explosion was synonymous with radiation, and therefore thought they had been exposed to harmful levels of radiation. This incorrect knowledge was mildly associated with poorer mental health.

Lead researcher Dr Yoshiharu Kim said: “Our study shows that being in the vicinity of the Nagasaki atomic bomb continues to be associated with poorer mental health more than half a century after the event. Fear about the potential radiological hazard and a lack of knowledge about radiological risk are responsible for this association.

“It is not unreasonable to assume that many people living in the vicinity of the Nagasaki explosion did not have access to official sources of information because they were not officially registered as being exposed to the radiation. But our study shows that public health promotion beyond the contamination boundary is important, otherwise people’s anxiety may persist over decades.”

Dr Kim continued: “Our study also provides some insight into the nature of the distress related to the nuclear power plant accident that occurred on 11 March 2011 in Fukushima, Japan. Beyond the officially-recognised contaminated areas, low-level radioactive substances were released over a wide area. Although experts agree that the effects of this low-level radiation pose only negligible risks to health, considerable distress and anxiety has occurred among residents in the affected areas. We hope our findings from this study will be useful for helping to devise effective measures to counteract the distress of people like those in Fukushima.”

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Kim Y, Tsutsumi A, Izutsu T, Kawamura N, Miyazaki T and Kikkawa T. Persistent distress after psychological exposure to the Nagasaki atomic bomb explosion. British Journal of Psychiatry 2011; 199: 411-416


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