Narcissism and psychopathy are so fascinating because they can simultaneously help individual leaders advance their careers while hurting the people and organizations they lead.

Meta-analytic studies suggest that the gender differences in narcissism have indeed been declining over the past few decades, largely because women have become more narcissistic, rather than men becoming less so. This change reaffirms the danger of encouraging women to lean in or act more like men to climb the corporate ladder. We are only inviting them to strengthen a problematic leadership model and augment rather than reduce current incompetence rates.

Narcissists may charm others initially, but these first impressions usually wear out in the end. For example, a recent study collected longitudinal data from 175 retail stores in the Netherlands, spanning three years. The results showed that the more employees knew—and interacted with—their managers, the more negatively the employees viewed managers with higher narcissism scores. In other words, as long as bosses had limited interactions with their employees, their narcissism did not automatically translate into a negative reputation. However, it was far more unlikely that narcissists maintained a good image with employees after prolonged interactions with them. These results are consistent with much research showing that it can be particularly difficult for narcissists to maintain long-term relationships.

First, narcissists are significantly more prone to counterproductive and antisocial work behaviors, such as bullying, fraud, white-collar crime, and harassment, including sexual harassment. And, given the contagious nature of these toxic behaviors, their teams and organizations are more likely to engage in these unethical and destructive activities as well.

Second, although narcissists generally perform perfectly well just after their promotion to a leadership role, this usually short honeymoon period is followed by a much bleaker phase. For instance, narcissistic leaders, especially narcissist CEOs, are paid more than their counterparts, and they are also more likely to push their organizations into extravagant acquisitions and other investments without, unfortunately, producing a higher return on investment (ROI).