I know someone who I personally think is on the verge of going off on the deep end and developing full blown schizophrenia. I think its long time marijuana abuse. Dude is in his late 20's and has been smoking since he was 14.
One night we were leaving a strip club and he was ranting about two women who were in the club sitting across who were completely oblivious to who we were or what we were doing. Since the club was about to close they started to leave a little after we exited and he became increasingly paranoid. He just kept going on about keeping our eye on them as they got into their SUV, rambling nonstop about them wanting to follow us while the whole time I was trying to figure out where this panic was coming from

. I literally had to sit in the car with him and talk him down so they could leave before we did and they were no longer a threat in his mind. On the way home he wanted to argue with me why they were following us by bringing up details of things at the club that never even happened....

.
He's quit smoking just a couple of months back to get a new job but I feel like something's still off.