My father manipulated/coaxed/trained me in being very derisive about my crazy mum (and other relatives). My mother was manipulative in her own way and well, crazy , a bit less than I am now. My father drank quite a lot. Less so now. My father tried to do anything to keep me from being like my mother and had from a early age convinced me, and made me identify with extreme rationality, that I wasn't and that craziness is of course, a choice. Any troubles were a choice I made and my mother was to blame. Both were verbally abusive and manipulative and my father was physically abusive, mildly but impressive enough at a young age. He threatened me more often with physical abuse though (not verbally).

I still probably don't realise the extent it affected me. The love of my parents was extremely conditional and they manipulated me and I learned to effectively hate myself. But I didn't realise it and I've forgotten (and repressed) a lot of it.

It comes back to me very slowly, bit by bit. Obviously not the nice bits.

It's the manipulation which might even make a perfectly sane child disturbed.

Edit:
I forgot: actually it has. Because my sister also became like me and then also turned against me and my mother. She is as far removed from being BP as can be. She does see a therapist regularly. Also because my borderline craziness (of course hadn't fully blossomed) caused me to be an expert in cold vengeance.

I was rather out of control. There was one incident where I got physical (it was mostly just anger, lying, overindulge and manipulation) and someone (a friend) needed medical attention and the reaction of my parents (mostly my father) and the impact of this and all previous times I had been out of control (which I was maybe from pretty much day one) caused me to gradually become severely depressed for a few years.

It took me seven years to recover and I'm pretty sure it allowed me to let the BP emerge: first, my personality was no longer suppressed, then only hypomania and depression and a few years later the first long periods of mania, mixed state(s) and severe depression.