Craig Malkin, a lecturer at Harvard Medical School and the author of "Rethinking Narcissism," told Psychology Today that there are different types of narcissists.
For example, some are "communal," meaning they're so altruistic it's almost sickening. Others are "vulnerable," meaning they're sensitive to criticism and need constant reassurance.
But Malkin said all narcissists have "self-enhancement" in common: They somehow stand out from the pack.
Ultimately, it's a way of masking an unstable self-image. Eddie Brummelman, a developmental psychologist and a fellow at Stanford University, told Psychology Today that while narcissists feel superior to others, "they are not necessarily satisfied with themselves as a person."