I take a drug in the same class as risperidone, called Geodon, which is weight neutral. I do really well on it, but it does "dull" me a bit, although that's not ALL a bad thing. I would say ask the doctor why he or she is choosing this drug for the girl, and see what he has to say. Don't take the responses of people on an internet board above the advice of a doctor. Everyone reacts differently to drugs, and just because some people here have had a bad experience has no bearing on your niece's reaction to the drug. All that said, I don't believe in medicating anyone, 4 years old or not, unless it's absolutely necessary... and it would have to be a pretty out-of-control 4-year-old for me to agree to medicate her. Your sister should see a doctor with whom she has a good enough relationship that she can express that and the doctor listens.