Replying to Insane Neighbor

I am sorta freaked out right now. My neighbor went away for a while (not sure how long) a couple days ago and left his kid who is a couple years older than me (like 22 or something) in the house alone. This guy is fucking nuts… I don’t know what the hell he is on but he is running around his house as fast as he can, screaming as loud as he can. Like death screams, its fucking creepy as shit. I don’t know what to do… I don’t want to call the cops on him but its starting to get to me. He has been doing this shit for the last 3 days, 24 hours a day.

SO, what do I do?