iluvhim,
I have a 15 yr old son with autism and we have been through the med thing many times throughout his life. One issue we had with Adderall was that because it is prescribed for ADD/ADHD it is a amphetamine-kids/and adults with ADD/ADHD have a brain chemical imbalance and an "upper" has the opposite effect on them. If the imbalance isn't present then the hyperactive behaviors can become much worse,so we have to add things like risperdal and clonidine to bring them down. When we D/C'd the Adderall he didn't need the risperdal anymore but we kept the clonidine for the sleeping @ night. He also took clonidine during the day at first,a very low dose so he wouldn't sleep all day.
Risperdal as one other person said can come with pretty bad side effects that may not present until later, but can also be irreversible and they aren't minor annoyances either. A factor to research for sure if the doc is planning on keeping him on it.(Even a small dose).
Best wishes, rebecca