Reb E, I think all Presidents (and just candidates) have NPD, it does not detract from what they achieve. I don’t think ADHD is prevalent among Presidents.
ADHD is not lack of attention. As I understand it, “normal” person activates one area of the brain in response to a stimulus, an “ADHD” person activates multiple areas at the same time.
Many jobs require first type – pilots, surgeons, school principals. Others, like your son and like a lot of very creative people, do well in jobs that require combining multiple pieces of information, questioning the tasks they are given instead of following instructions they were given.
As most people are not creative, they are annoyed by more creative ones and trying to medicate or beat them into submission. If you show a page of Bavli to a psychologist, I bet Bavli will be given ritalin and told to go learn Shulchan Oruch like everyone else.