T.A.
I have taken quit a few classes in phsycology learning about children and their behavior. The one mom that gave you advise on having your son's eye's, ears etc..tested could also be right on target. Children will act out like this as well when they can not see or hear properly because they know no other way of dealing with thier problems and they do not know how to convey to you what they are going through. You can usually have this done through the school for free, you might want to check into it and I would also make an appt with your son's doc. Personally, I would rule out everything else before I would put my child on any kind of drug!!
Hope this was a little bit helpful, good luck to you and let us know what you find out.