Lithium has worked for a lot of people over the years, it's always worth a try. It did help me, but turned out not to be the best medication for me. There are a lot of blood tests required if your pdoc is aiming for a therapeutic dose.

I've heard of some people who experience few side effectd, others many. Lithium was weight neutral for me, but I had other side effects. Some that could be calmed with other medications, some that I just lived with. Though uncommon, I did develop a kidney issue. Because of that, my pdoc gradually weaned me off, but it was discovered early through the routine blood testing. My kidney issue doesn't require any treatment given its mildness, but must be monitored.