She needs to be on different meds or a different dose, but not off them completely. That almost always leads to immediate disaster. Meds + exercise + therapy are the only proven treatments for bipolar, and meds are key because you can't accomplish much in the other two if you're extremely depressed or jumping out of your skin and impulsive.

Diet (such as taking B vitamins, E, D3, and omega fatty acids) can help to improve the effects of the above, but they've not been proven to do the trick in any medical studies (in terms of instead of meds).

Hope your friend won't have to go to the hospital, but it's likely if she doesn't get back to the psych doc and get her meds reevaluated and go back on them. You can tell your friend that I had a bad experience (extreme depression and wanting to sleep all day) on seroquel. Now I'm on abilify and feeling much better. I'm manic, sure, but once they adjust my meds correctly, I'll just feel good and normal...not out of control or despondent.

We're all here if you need to talk in the future.