A new study has suggested that some forms of narcissism are - at least in the short term - beneficial, helping children navigate the difficult transition to adulthood, but not in late life.
"Most people think of narcissism as a trait that doesn't change much across the lifespan," said postdoctoral researcher Patrick Hill, who conducted the study with University of Illinois psychology professor Brent Roberts.
"But a lot of recent studies have shown that the developmental trajectory of narcissism goes upward in adolescence and what we call emerging adulthood - the late teens and early 20s, and then typically declines," he explained.
This reduction in narcissistic traits coincides with a decline in their usefulness, the researchers found.
Hill and Roberts surveyed 368 undergraduate college students and 439 of their family members to get a picture of the narcissistic traits of the students and of their mothers.
"We looked at three different forms of narcissism," Hill said.
The first, an inflated sense of leadership or authority, is the belief "that you know a lot and people should come to you for advice," he explained.
The second is "grandiose exhibitionism," being pompous, wanting to show off, and having an exaggerated sense of one's capabilities and talents. The third is a sense of entitlement and a willingness to exploit others for personal gain.
They found that young people who were high in the leadership and grandiose exhibitionism forms of narcissism were likely to report higher life satisfaction and well being, while mothers who had the same traits were not.
An exaggerated belief in one's own capabilities and prospects may help young people "navigate adolescence and the turmoil involved in trying to find a sense of identity," Roberts said.
Later in life, however, those same traits "appear to be related to less life satisfaction and a poorer reputation," he added.
The study appeared in the journal Social Psychological and Personality Science.