Professor Craig Neumann sheds light on a difficult question
Psychopathy is a pathological personality disorder that reflects interpersonal deceptiveness, manipulation, callous and remorseless use of others, along with impulsive behavioral style and overt antisocial behavior (ranging from aggression to violent criminal acts). Only a few features of psychopathy (glib, grandiose interpersonal style) overlap with narcissism… the psychopath is about taking advantage of people for their own selfish interests, or sometimes just to hurt people because they find that amuses them.
A grandiose (or malignant) narcissist may end up hurting others, but not because they find it enjoyable but more as a byproduct of thinking they are so great and whatever path they may choose, even if it involves rolling over people, so to speak, is OK given their ‘greatness’
DSM-based narcissistic personality disorder (which mostly refers to grandiose narcissism and is somewhat limited in capturing vulnerable narcissism), also involves personality pathology but involves an interpersonal style and way of thinking that revolves around maintaining an elevated sense of self-esteem and getting attention from others to keep their self-esteem afloat, so to speak… paradoxically, the narcissist is fundamentally dependent on others attention for self-esteem maintenance, while they also think they are far better than everyone else. While most people develop a healthy sense of self-worth, the narcissist requires other peoples’ admiration to have a sense of self-esteem (and thus the pathology and essence of their disturbed way of relating to others). The (vulnerable primarily) narcissist most definitely has a grandiose sense of self, like the psychopath, and they can have shallow empathy for others (because everything revolves around them), but they are not generally impulsive and aggressive like the psychopath.
The psychopath is completely dissocial, whereas the narcissist(s) will be social, but for their own self-esteem ‘boost’. The psychopath will be ‘social’ to take advantage of others in many more ways than the narcissist would ever do