Sometimes doctors use terms they think will help patients understand things.

I'd wonder in this case if your son has demonstrable smaller left lobe or other details. Doctors say things sometimes that really are not meant to be literally taken. One such common comment...is "you will need to be on this drug for life"... which is basically not a true statement for anyone. But they say it that way to send the message that "medical management will be needed from now on". So this doctor's statement to you may have sent an inaccurate impression to YOU. That needs to be clarified IMO.

Kids develop at different rates, and often behavior may lag in some.

I think Dr. Amen, and his Spect analysis would show exactly what you need answered in clearer terms.

http://www.amenclinics.com/meet-dr-amen/

Also a visit to our Tourette's board, may be helpful for you and your son. There are other ways besides drugs to help a developing brain:

http://neurotalk.psychcentral.com/forum25.html

Check out the "sticky" threads at the top of the first page at Tourette's. They are loaded with good information that may be helpful for you.