I don't think TV has anything to do with ADHD, honestly.  If anything, ADHD makes it easier to keep yourself entertained, or it certainly did for me.  It was about a five minute walk to my elementary school, but sometimes there would be little streams from melting snow, or blowing leaves or little frozen puddles in the gutters and I would end up playing games like breaking the ice in a particular order (actually the order was always 'whatever I felt like) and then I'd arrive at school two hours late to the great distress and puzzlement of all adults involved.

Also, I'm pretty sure ADHD has as solid a physical/neurological basis as ASD, check the wiki page.