http://www.washingtonpost.com/national/fear-is-potent-risk-of-japanese-nuclear-crisis/2011/03/14/AB76TxV_story.html

When it comes to the nuclear power disaster unfolding in Japan, there is far more to fear than fear itself. But fear is one of the biggest — and could turn out to be the most potent — dangers.

Although radiation escaping from a nuclear power plant catastrophe can increase the risk of many cancers and other health problems, stress, anxiety and fear ended up in many ways being much greater long-term threats to health and well-being after Chernobyl, Three Mile Island and other nuclear accidents, experts said Monday.

“The psychological effects were the biggest health effects of all — by far,” said Fred Mettler, a University of New Mexico professor emeritus and one of the world’s leading authorities on radiation, who studied Chernobyl for the World Health Organization. “In the end, that’s really what affected the most people.”

Fears of contamination and anxiety about the health of those exposed and their children led to significantly elevated rates of suicidal thinking and anxiety disorders, and rates of post-traumatic stress disorder and depression about doubled, Mettler and others said.

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In fact, radiation is a far less potent carcinogen than other toxic substances. Studies of more than 80,000 survivors of the Hiroshima and Nagasaki blasts have found that about 9,000 people subsequently died of some form of cancer. But only about 500 of those cases could be attributed to the radiation exposure the people experienced.

The average amount of radiation that victims in Hiroshima and Nagasaki were exposed to would increase the risk of dying from lung cancer by about 40 percent, Boice said. Smoking a pack of cigarettes a day increases the risk of dying of lung cancer by about 400 percent.

“Radiation is a universal carcinogen, but it’s a very weak carcinogen compared to other carcinogens,” Boice said. “Even when you are exposed, it’s very unlikely you will get an adverse effect. But fear of radiation is very strong.”