Try to find any means necessary to help her out. But your common sense is telling you the right answer. If you aren't happy, if she's off her rocker bat shit crazy to you and can't handle herself and her own problems, why would you stay with her? If she continues to act like this and you stay and tolerate this kind of behavior, the message that you are sending her is that what she is doing is okay, because no matter what she does, she still has you in the end.
Do what you gotta do. You can let her go, you can live without her, and everything will be alright.
Waking up next to a beautiful girl,
Step outside and say hello to my beautiful world.