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Change in neuroticism tied to mortality rates, researcher says

April 17, 2007

While mellowing with age has often been thought to have positive effects, a Purdue University researcher has shown that doing so could also help you live longer.

Dan Mroczek (pronounced Mro-ZAK), an associate professor of child development and family studies at Purdue University, compared neurotic and non-neurotic men over time and tied change in the trait with mortality.

"We found that neurotic men whose levels dropped over time had a better chance at living longer," Mroczek said. "They seemed to recover from any damage high levels of the trait may have caused. On the flip side, neurotic men whose neuroticism increased over time died much sooner than their peers."

A neurotic personality was defined as a person with the tendency to worry, feel excessive amounts of anxiety or depression and to react to stressful life events more negatively than people with low levels of the trait. Neuroticism levels were measured using a standardized personality test.

Results of the study will be published in the print edition of the journal Psychological Science in late May. The study is available online at http://www.psychologicalscience.org.

In the study, researchers tracked the change in neuroticism levels of 1,663 aging men over a 12-year period. Using the data gathered in the first analysis, researchers calculated the men's mortality risk over an 18-year period using the average levels and rates of change.

By the end of the study, half of those men classified as highly neurotic with increasing levels of neuroticism had died while those whose levels decreased or were classified as less neurotic had between a 75 percent and 85 percent survival rate.

Even small increases in neuroticism were shown to have negative effects. Participants with as little as a one-unit increase in neuroticism over the course of the study were shown to have a 40 percent higher chance of death than a participant who showed no change.

Data was taken from the Veterans Affairs Normative Aging Study, a longitudinal investigation of aging in men founded at the Boston Veterans Affairs Outpatient Clinic in 1963. In 1988, the beginning of this study, the men ranged in age from 43 to 91.

Mroczek and Avron Spiro, an associate professor of epidemiology at Boston University's School of Public Health, also controlled the data for age, depression levels and both subjective and objective ratings of overall health.

"We found that neuroticism levels are a clear indicator of how long one can expect to live," Mroczek said. "The link between mortality and the rate of change in neuroticism is similar to the way we think about change in high blood pressure and risk of heart attack. If you have high blood pressure but make sure to lower it, you are likely to reduce your heart attack risk."

While those who were very neurotic and grew worse over time had a higher death rate, those who were the least neurotic and improved over time did not die at a significantly lower rate.

Mroczek said the anomaly could be traced to how these types of attitudes affect personal choices.

"It's possible that the key with neuroticism is having just the right amount," Mroczek said. "If you are too laid back, you may not be taking your health seriously enough. These folks might be engaging in more risky behaviors like smoking or drinking to excess because they don't believe anything bad will happen to them."

Mroczek, a member of Purdue's Center on Aging and the Life Course, said he sees a future in which doctors and other health practitioners include some form of personality assessments with routine medical screenings. Learning to deal with some of the potentially negative aspects of human personalities in a positive way could become part of a balanced and healthy lifestyle.

"For example, very neurotic people can work toward dealing better with stress," he said. "They can seek therapy, take up yoga, schedule daily walks to help themselves unwind, listen to calming music or even meditate."

While participants in the study were male and more than 90 percent Caucasian, Mroczek said there is little reason to believe that results for women or other ethnicities would show vastly different results.

"You can find the full range of personalities in any ethnic or gender group," Mroczek said. "There are those who are laid back and then there are those who worry, who react very poorly to stress, who are always on edge."

Mroczek will begin testing later this year to determine why higher levels of neuroticism increase mortality. He plans a study which tests cortisol levels in neurotic men to determine if they have higher levels of the damaging stress hormone that could contribute to early death. Other possible contributing factors might include unhealthy coping techniques, such as overeating or drinking to excess.
This study was supported by grants from the National Institute on Aging and by the Clinical Sciences Research and Development Service of the U.S. Department of Veterans Affairs. The VA Normative Aging Study is supported by the Cooperative Studies Program/ERIC of the U.S. Department of Veterans Affairs and is a research component of the Massachusetts Veterans Epidemiology Research and Information Center.

Purdue University