Trileptal is usually weight gain free. I take that now. I was on Lithium for a month and I gained 20 pounds. It was awful. But I know that there are people who take Lithium and have no weight gain. I guess it depends on your body. Check out this site on mood stabilisers:
http://home.comcast.net/~pmbrig/BP_pharm.html I find it helpful.

It's funny, my doctor used Seroquel as a mood stabliser for me. Will you be coming off the Seroquel?