Unfortunately, weight gain is a common side effect of risperdal. My son is on this medication, too.
We just added the med. mentioned in this article (Galantamine). http://pn.psychiatryonline.org/cgi/c...ull/36/14/19-a
I don't know if it will be helpful, yet, or not but I thought I would pass along the information in case you were interested.
It makes alot more sense to me to target the part of the brain that might be part of the problem then just giving a drug and hoping for the best (that's just my opinion).