Sara Konrath, a University of Michigan psychologist; David Reinhard of the University of Virginia; and William Lopez and Heather Cameron of the University of Michigan said their earlier research found the level of narcissism -- an inflated sense of self-importance, overestimation of uniqueness and a sense of grandiosity -- is rising in American culture.
The researchers examined the role of narcissism and sex on the stress hormone cortisol in a sample of 106 undergraduate students. Cortisol, measured through saliva samples, is a widely used marker of physiological stress.
To assess participants' narcissism, the researchers administered a 40-item narcissism questionnaire that measures five different components of the personality trait. Two of the components are more maladaptive, or unhealthy -- exploitativeness and entitlement. The other three are more adaptive, or healthy -- leadership/authority, superiority/arrogance, and self-absorption/self-admiration.
The study, published in the journal PLoS ONE, found the most toxic aspects of narcissism were indeed associated with higher cortisol in male participants, but not in females. In fact, unhealthy narcissism was more than twice as large a predictor of cortisol in males as in females.
The study found there was no relationship between healthy narcissism and cortisol in either males or females.