I watched some clips from Burnish.net (btw, thanks to the people posting it!) and the head-twitching, thát's epilepsy. I've exactly the same thing, it's weird to see someone else do that, actually!
It can be slightly annoying, but you can compare it to shivering with cold. Nothing painful or dramatic. (as long as it doesn't develop into a real seizure, of course)
But the other stuff... pffff, he's just neurotic
Allthough, there are anti-epileptics that actually make you feel nervous, aggresive, agitated. But it's difficult to say, thÃ*s is an effect of the medication, thát isn't. Doesn't work that way.