Editor's note: Evelyn Bromet, is Distinguished Professor of Psychiatry and Preventive Medicine at Stony Brook University in New York.
(CNN) -- The frightening disasters in Japan are mounting. Despite workers' Herculean efforts to prevent a complete meltdown at the country's earthquake-ravaged Fukushima Daiichi nuclear power plant, the situation appears to be growing more serious.
In fact, each of the catastrophes that have struck Japan since last Friday--the earthquake, the tsunami and now the potential of nuclear calamity--would have been singularly perilous to the Japanese public's psychological well-being. Their collective impact on mental health is unimaginable.
And mental health is just as important as physical health. We know from years of research that poor mental health leads to physical health problems, diminished quality of life, work-related problems, social and family dysfunction, and even early death.
When the partial core meltdown happened at the Three Mile Island plant near Harrisburg, Pennsylvania, in March 1979, people in the surrounding communities were frightened and bewildered by the confusing and contradictory information being disseminated about what exactly was occurring at the reactor and whether their health was at risk. Moreover, the population nearby was advised to evacuate and evacuation discussions were also held as far away as Philadelphia.
The President's Commission on Three Mile Island documented an immediate impact on mental health, with high levels of depression, anxiety and somatic symptoms like headaches and stomach pain in all segments of the population. The report also described the alarming increase in distrust in authorities that arose amidst the perplexing, ambiguous, and inconsistent statements.
In the end, Three Mile Island proved to be a near miss, and the level of radiation was not sufficient to cause cancer. But the fear engendered by the perceived exposure to radiation had long-term consequences.
I lived in Pittsburgh at the time and had started a new mental health research program at the University of Pittsburgh. I was asked by the National Institute of Mental Health to investigate the psychological consequences of the accident.
Ultimately, we identified a very high risk group--mothers of young children living near the plant. We interviewed them several times in the first few years and found rates of depression and anxiety double that of a comparison group.
At the 10th anniversary, we again inquired about their mental health and their beliefs about how the accident affected their health. On average, the level of depression and anxiety was as high as it had been shortly after the accident, and worse than expected based on community studies.
Beyond that, 75% said they were currently worried or uncertain about the effects of the accident on their health or their children's health. The concerns were the driving force behind their mental health symptoms.
Seven years after Three Mile Island, in April 1986 in what is now Ukraine, the Chernobyl nuclear reactor exploded. The surrounding community was permanently evacuated. Many were resettled in Kiev, south of the plant. They were not welcomed by their new communities. Rather, they were stigmatized and initially feared, even though there were no official statements that anything had actually occurred at Chernobyl.
However, some people had access to radio broadcasts from outside the Soviet Union. And then the rumors started to spread, and these rumors were reported in the media -- stories about birth defects, hundreds of thousands of deaths and cancers arising in countries miles away.
Eleven years later, in 1997, and then again 19 years after the Chernobyl catastrophe, I and my colleagues, together with researchers in Ukraine, interviewed evacuees who were resettled in Kiev. They came there with small children, who were given full medical examinations and basic blood tests. Compared with a similar group of women who lived in Kiev when Chernobyl exploded, twice as many evacuees had post-traumatic stress disorder and major depression at both interviews.
At the same time, almost every evacuee mother and most of the Kiev mothers worried that their health had been affected by the accident. And of course, the more worried they were, the worse their mental health.
Many women and their children sought help from their doctors and were given diagnoses linked to their Chernobyl exposure. To this day, these diagnoses have not been verified by impartial doctors. (In fact, the only documented physical health effect of Chernobyl is thyroid cancer occurring in children and clean-up workers). Yet the more such diagnoses the mothers and their children received, the worse their mental health.
In the past few days, hundreds of thousands of people in Japan have lived through horrendous disasters and are now homeless. Some will develop significant post-traumatic stress symptoms from these experiences.
Many have been and will continue to be exposed to radiation and will develop both persistent fears about their health and long-term depression, regardless how much actual radiation exposure they received. To be sure, one of the biggest health effects of the current catastrophes will be on mental health.
As a researcher -- but also as a mother and grandmother -- I want to share some important lessons I learned from Three Mile Island and Chernobyl. First, the psychological "fallout" of the radiation leaks will not just be widespread. It will also be long-lasting.
Government officials and physicians should therefore be straight and open with people about their exposure, should treat mental and physical health problems with equal respect and care and should understand that mental and physical health go hand-in-hand. Second, even when the next disaster happens in another place in the world, the victims in Japan should know that we will always remember their painful experiences and they are not suffering alone.
The opinions expressed in this commentary are solely those of Evelyn Bromet.