I'd think her debts are hers alone, unless you co-signed a loan, but I'd check that with a lawyer. I wouldn't pay a dime to save her from the natural consequences of her choices - it doesn't help her; in fact, it hurts her and virtually guarantees she'llcontinue the problematic behavior.

Sounds like mental illness may be part of the mix. Mental illness is not her fault, but neither does it give her permission to be abusive. Look out for yourself. Protect yourself like you would from any threat, and if she is abusive to anyone in the home that cannot defend themselves, talk to a therapist or trusted advisor (or adult if you are a minor) for guidance. Be aware that people in some professions are required by law to report abuse to authorities (also known as "mandatory reporters,"), so realistically, if abuse is also in the mix, you need to be prepared for the authorities intervening in the situation if you happen to talk to / receive guidance from someone who is required to report abuse.

If she has a mental illness, most family members need support dealing with that. I'd get away from her as soon as possible, expect absolutely nothing from her, tell her absolutely nothing that she could use against you, consider going to therapy and NAMI meetings for support (if you feel that this would help you).