For me, the pages below (click on link), from Patricia Evans’ book “The Verbally Abusive Relationship“, describe EXACTLY what my Ex acted like and gives some very interesting insight into WHY he may behave the way he does, if not from physiological factors.
He claimed his sisters treated him badly as a child. He despised them and apparently didn’t get along well with them.
Oddly, The Ex had NO close or emotionally substantial relationships with ANYONE in, OR outside his family. I SHOULD have seen this as a warning sign about him regardless the potential cause physiological or psychological, but I either did not see it, or denied it. It is common for a narcissist / psychopath to lack empathy, and the ability to form emotional attachments to others beyond an initial infatuation that just as quickly turns to degradation and abuse – both common narc/sociopathic traits.
I believe this is the crux of the abusive relationship I had with him – regardless the cause.