I agree with DJ on this, any forms of abuse can certainly be a triggering factor.
My former T and pdoc, explained that even if a person is set up genetically to be bipolar, but hasn't or never had any symptoms, a major life event can trigger it, or exacberate situations.
Part of this, some researcher's claim is how the brain handles and processes the stress, the brain chemistry becomes effected, neurotransmitters/receptors become messed up, out of balance.
This doesn't mean everyone who experiences some horrible things will become bipolar, but if it's in the genes there is always a good chance of it surfacing.
Medications prescribed by a pdoc help get the imbalance(s) stabilized and talk therapy can help in adjunct.
I'm wishing you lots of luck with all of this.
Take care,
DE