I am also NOT an MD, but with our experience with dd10 and the schools begging us to medicate her for ADHD, I am glad I found this list of 50 diagnosis that mimic ADHD. For DD10, we discovered that although gifted, she was also having focal seizures along with being stealth dyslexic and dysgraphic. I am not suggesting that your child is any of those things...here is the list if you like:

http://www.incrediblehorizons.com/mimic-adhd.htm