I experienced psychosis following some a dose of 200 mics of LSD (not personally tested, but from a trusted source) last summer. I was experiencing obvious symptoms for about a week before I was hospitalized, such as extremely out-of-character manic behavior that certainly should've cost me friends, and definitely would have left unchecked for any longer. At the time I just felt on top of the fucking world, like it was reshaping itself in my image. The night I truly broke, I was 100% certain that my apartment was about to get raided, and immediately left out of town with my laptop and desktop's hard drive, leaving my phone at home. Made a bunch of erratic path changes to shake my supposed tail, then threw the laptop into a river and the hard drive off a cliff. I proceeded to get my car stuck in a ditch, but by sheer luck I could see a single house a little ways down the road. I knocked on the door and met a very nice older couple, who coincidentally owned a tractor and got me out of the ditch. Drove back into town and ended up my father's house, he calmed me down a little bit, but by this point I was completely off my rocker. It felt like someone else was speaking through him and directly into my mind. It did not help that he was sitting in front of his flatscreen that he used for a computer monitor, which had a picture of HAL (the AI from the film 2001) on it when I walked in. I recall the screen switching to a bright white when I laid on the living room couch in front of him, leaving him a silhouetted, blank figure. My attention slipped between him talking slowly at me, and the conversation going on in my mind. The screen would change colors from red to green to blue, seemingly dependent on my responses to what was happening to me. It almost seemed as if it was some sort of clinical examination. Around 3 am I guess, my father got up, walked robotically to bed, and began to snore immediately. I fell asleep thinking I had just talked to God.

Anyways, the next morning I ended up freaking out even harder than the night before after a bong hit. Now that my dad was a bit more sober (he is a hardcore alcoholic and absolutely had to have been wasted when I walked in), he called an ambulance. I was in the hospital for 2 weeks, though my mental state was still in bad shape even when I got out. I can elaborate on the rest of my experience if there's interest, but it took around 5 months before I would say I was back to near normal. I still dream about it often. But yeah, seeing figures out of the corner of your eye and shit in the dark is probably not psychosis, but if you are worried please talk to a psychiatrist or other mental health professional.