Men who show many signs of narcissism, such as those who are typically described as 'vain' in the way they take excessive measures in making sure they always look gorgeous in social situations, quietly suffer from stress levels that are more taxing than what women experience for the same thing, according to researchers.

Narcissism is not limited to vanity, the study implied.

The scientists defined narcissism as "an inflated sense of self importance, overestimation of uniqueness, and a sense of grandiosity."

The study's co-author, David Reinhard of the University of Michigan, said:

"Even though narcissists have grandiose self-perceptions, they also have fragile views of themselves, and often resort to defensive strategies like aggression when their sense of superiority is threatened."

Men's self-esteem dictates the manner in which they take care of themselves physically or otherwise in social situations.

The study was done to find out whether vanity and other signs of narcissism have certain effects in men's psyche, particularly in terms of stress levels.

American psychologists asked 106 men and women to take personality questionnaires and took two saliva samples from them to measure levels of cortisol, a stress-related hormone.

The study authors found that men who reflected "unhealthy" levels of narcissism in the survey also had high levels of cortisol, even when they are relaxed. In contrast, "vain" women showed normal levels of cortisol.

Dr. Reinhard said the results suggest that men take social pressure harder than women when it comes to looking good.

Professor Sara Konrath, lead author of the study, which was published in the journal PLoS ONE, said: "Narcissistic men may be paying a high price in terms of their physical health, in addition to the psychological cost to their relationships."

Apparently, vanity does not happen instantly. Dr. Reinhard said acts of vanity may all be just a way for narcissists to cope with the world.

"These kinds of coping strategies are linked with increased cardiovascular reactivity to stress and higher blood pressure, so it makes sense that higher levels of maladaptive narcissism would contribute to highly reactive stress response systems and chronically elevated levels of stress."

A "healthy" degree of narcissism is good for everyone, said the study authors. However, when it has become too much, the vain person could wind up experiencing tension and in extreme cases, even depression and personality disorders.

The study also found that there was no relationship between healthy narcissism and cortisol in either the men or women.

The study's authors would like to further explore the results of their study to understand links between cortisol and vanity against different genders, as well as determine why vanity does not increase cortisol level among vain women.