I remember specifically trying to hallucinate (visually) while very high on marijuana and I couldnt no matter how hard I tried.
This was at a period of my life when things were pretty bad and I was living half awake, I was very sleep deprived it was during school so I was very stressed out. I decided that I no longer wanted to live in this shitty world and I wanted to live in the cartoon world forever. Kind of weird, but I think we can all relate to some degree lol. Anyways I tried for a couple weeks to hallucinate and live amongst the cartoons in fantasy world, but I couldnt. Never had one hallucination. Keep in mind that I actually probably should have. I remember smoking a whole blunt of weed, going home and sitting in a dark room hoping cartoons would come alive, I was sleep deprived too, but still nothing. That tells me its pretty hard to hallucinate visually with weed. I was smoking pretty shitty quality stuff at the time though, but still. So with marijuana, delusions and ocassional mild audio hallucinations, yes. Visual Hallucinations, no. Just doesnt happen in my experience.