Do you mean physical abuse or emotional abuse?
There's this common stereotype that a lot of physical abusers have an addiction problem, especially alcoholism.

Maybe, who knows?

I don't think it's a brain structure issue most times, i think most times they simply came from an environment where violence was demonstrated to be an acceptable behavior.

And i think perhaps it is an inferiority complex. Because I've noticed that the men who hit women tend to be little dogs rather than big dogs so to speak.

Rare to see a big burly dude hitting on his woman. Usually it's a little guy who his woman could probably handle if she had the mind to go toe to toe with him.

I think it's NPD and BPD (borderline personality disorder) and subtypes of sociopath disorders such as "sadistic personality" they enjoy inflicting pain on others