I agree with Kristen-- don't rely on the ped.'s assessment. Our very good ped. just couldn't see DS's Asperger's for years.
You would know very quickly if the classic ADHD meds (stimulants) improve things; and probably also quickly if they make things worse. Be aware, though, that some kids get too hyped up on these meds (think too much coffee, irritable and sleepless). This is all the more true if it's an anxious kid to start with. I would be concerned about giving stimulant ADHD meds to a child who is already underweight, because they can suppress appetite.
Asperger's can look a lot like ADHD; many doctors feel that Asperger's includes a significant attention component, some are willing to dually diagnose. You might want to find a highly trained specialist to help you tease out these issues.
Best wishes,
DeeDee
