if your parent has a mental illness, especially a personality disorder, they might shape your identity like an impression of their illness into you, if that makes sense. then you have to really make an effort to undo that. sometimes abuse is really just a parent teaching their child what they've been taught, maladaptive and harmful coping mechanisms. i think its easier to look at it that way.
another thing, hypervigilance, i think its called, thats when you are extremely sensitive to reading facial expressions to predict the random outbursts and get out of dodge from your parents, if you had that kind of fun as a kid. that carries over to dealing with people later and definately links abuse to sa.