If you believe your appetite issues are hormone related, you might want to also discuss this issue with your gynecologist. I don't know if you are on birth control or not, but perhaps that might be a factor to consider. Note that even some birth control meds can be triggers for mood issues, while others not as much. I can say that my gynecologist seems to have a pretty good idea of which choices were best in that regard. Nowadays there are some BC options that are good (or bad) for various things, over others.

If your appetite is influenced by bipolar medications, there are ways that your psychiatrist can work with you. They can either change medications or adjust doses, but if your current mix works, it would be a shame to make changes if your appetite issues have nothing really to do with the bipolar meds.

I know people out there have taken metformin for weight loss (even without diabetes), but once when I asked my psychiatrist about it, he literally yelled "NOOOOO!" Medication changes and dieting eventually solved the weight problems I had. Obviously some people have no problems with metformin, but my sister (who has type 2 diabetes) experienced some pretty nasty side effects from it, plus it is not such a wonder weight loss drug for everyone. It wasn't for my sister.