Over the counter pills never worked for me. Also, I've heard that the risks for stuff like SAM and St. John's Wort are similar to the risks of prescription medications. Plus, if for some reason things don't go the way that you expected or the way that you want them to, who would you call for assistance? It's not like there's usually a local expert on vitamins and OTC pills and their usage with whatever flavor of bipolar disorder you have.

If you're hurting enough to play the role of being your own researcher, diagnotisician, doctor, and pharmacist, I guess you have little to lose... good luck to you.