He doesn't strike me that way at all. He seems to be one of those people that are gifted either because of, or in spite of, their Aspergers, so it's more than likely he doesn't use anything that could be called drugs.
I think he's much more likely to be some sort of nutritional, diet, or exercise fanatic. If he is into exercise I hope that doesn't include too much public dancing, as the footage of his dancing at conferences or infront of the press are just about the most cringey things I have ever seen. Public dancing and Autism sometimes seems to be a very bad combination. Maybe that's why you think he uses drugs? He's obviously not inhibited, but that could be for many different reasons.