That clip looked more like a typical tick of his when he knows he can be seen or heard. He cannot sit still when interacting with others in any way, his social anxiety has only gotten worse over time, which has me attributing it to his increasing level of intolerance for others, and heightened level of paranoia. Basically, he already hated people, and now he hates them even more, but also has shit to hide from them. Not a good combination when you're also incredibly insecure and can't go on living without the adulation of those you hate.
As for the more extreme example you're referring to, I don't know what that was, but it was probably a symptom of a medical problem. It didn't look like a tick to me.