I was misdiagnosed as ADHD in third grade. And by the leading expert at the time, a Dr. who is still highly respected in the field of medicine and this specialty. I was taken off ritalin when it was clear it was not affecting the behavior.
Admittedly, looking back, my behavior was classic ADHD, which of course, I don't like to admit. smile
My husband does have ADD and his behavior is markedly different when he takes his medicine. I can tell you within 15 minutes after he wakes up whether or not he takes it. He's extremely argumentative and intense emotion seeking (usually needles me until I start yelling). When he has taken his concerta he just doesn't do it. If the concerta didn't work, I'm not sure we would still be married. smile
We were concerned DD5 had ADHD, but one of the things I was told is that she concentrates fine when she wants to/is interested. It is a behavioral issue, just not ADHD.
I'm not trying to say you son doesn't have ADHD, good grief, I certainly would't know!!! smile For all I know my daughter does have ADHD and they are attributing to0 many of the traits to giftedness, and I will keep an eye out just in case, given the family history.
I am biased, though, at having a pediatric nuerologist or psychologist/psychiatrist make that diagnosis, vs. a pediatrician. Just because of my personal experience. Just being honest about where my bias lias. smile
Whatever is going on, we all know our kids can be a REAL BIG handful, and I can tell you are the kind of mom who is up to the challenge.

P.S. feel free to meet me in the back of my virtual closet with my virtual bottle of vodka any time!!!!!!!!!!!!

Neato