This week Insight explores narcissism: what causes it, whether social media is feeding it, and when narcissistic tendencies verge into serious disorder. Narcissists have an inflated sense of self, a lack of empathy and can be vain and materialistic. But narcissism can be far more serious and destructive than simply an overblown ego. While the spectrum of narcissistic personality disorder is broad, those at the severe end of the scale can tear apart the lives of the people around them.