Another data point: I have anxiety and weed/hash reduce my anxiety, it helps a lot with falling asleep while I'm awake but I'm known to scream while sleeping under the influence; another time I was sound asleep near a friend who was snoring and his snoring woke me up and I was convinced he was in fact drowning in his own vomit and I slapped and shook him and tried to get him on his side, after I realized he was fine, I happily went back to sleep as if nothing happened.

I also had visual hallucinations, visual/auditory synesthesia once from a high dosage of hash, so I might be an outlier.