Replying to Weird/Scary Roomate

So theres a guy who lives in the downstairs part of the house I live in right now. The few times I have talked to him he seems pretty normal-ish. But as the semester went on me and my actual roommate kept noticing weird things he would do.

It sounds as though he is running around down there. Like sprinting sometimes. He also makes clapping sounds that are really loud....but it isn't clapping. Its like hes slapping the shit out of himself somewhere multiple times over and over. He also yells really high pitched when he is doing all of this. I can not ever understand what he is yelling. So we have the running, yelling and slapping and this happens in random combos almost everyday. Sometimes he goes absolutely crazy down there, to the point where we get scared.

He also sings opera type music sometimes really loud. Think Tiny Tim type stuff. Really creepy.

We think its either turrets or a similar dysfunction, he has some weird webcam going and does that stuff online, or its hard drugs. His apartment it also really really messy and gross. Shits really starting to scare us.