A big ego can be important to someone angling for the corner office. But once a true narcissist is in that office, look out — eventually, the ugly traits of arrogance, manipulation, exploitation and self-centered behavior will emerge. And the early promise of true leadership rarely follows.

These are some of the musings derived from a University of Illinois review of 54 studies of narcissists produced during the last several decades. Researchers were testing the oft-repeated notion that narcissists make good leaders. Essentially, what they decided was that narcissists are good at getting leadership positions, but often fall short when it comes to on-the-job performance over time.

The study, titled "Narcissism and Leadership: A Meta-Analytic Review of Linear and Nonlinear Relationships," says that the extrovert within the narcissist gives the job candidate a leg up on others.  But, the authors wonder, could it be merely the narcissist's gift of gab that gives them the edge, "as opposed to extraverted characteristics such as dominance, self-confidence and self-promotion" which might actually serve both individual and company well in some cases?