Much has been written on the subject of narcissism: extending beyond personal boundaries and spreading, uncontained, onto someone else's turf; the inability to appreciate others who are viewed as mere extensions of one's self, or mere reflections.
Narcissists are extremely insensitive to others's needs, holding no regard for differences and all but obliterating separateness. Nobody likes a narcissist!
At the other end of the sepctrum are people so exquisitely sensitive to others's needs (perhaps children of narcissistic parents) that they have no filter for someone else's drama. This is what I call reverse narcissism: the absorption of someone else's problems as if by osmosis. Reverse narcissists are so thin-skinned that others' realities can be experienced as intrusive or invasive.
Just as the narcissist can be so tactless and brash you want to put a mute on him, the reverse narcissist can be so vulnerable you want to give him a megaphone and some clothing, preferably a suit of armour. And that's precisely what he has learned to do to protect gimself when he feels threatened by others. He may suddenly trumpet "my needs!", "my time!", "my things!", "my space!" and withdraw to reclaim them, or use more drastic measures like bingeing, drugging or gambling to "numb out".
Unlike empathy which vibes with someone else's experience while maintaining ego separateness, reverse narcissism absorbs others' experiences to the point of saturation and flooding, threatening the very survival of the ego. It's intolerable. At that point, trying to buffer himself against another's reality, it might look and sound as self-absorbed as the narcissist but is actually the reverse: a gasping and grasping for air and dry land to avoid being engulfed by another...