I was looking through these posts, and I noticed your questions about tapping and nervous movements in your son once he started medication. When I began taking ssris, I experienced the same thing. I asked a psychiatrist about my hyperactivity and compulsions to tap, and he said that this may be caused by the anxiety side effect that these medications have. Also, he suggested that the brain activity involved in ocd drains a lot of mental energy that would otherwise be routed toward other activities. This may explain why your son appeared hyperactive after beginning medication.
My doctor prescribed a calming medication to balance out the anxiety caused by my anti-obsessional medications. It worked very well for me, I'm not as restless now. I hope this info helps out a little bit. : )
Meghan Nicole