I think it's too common a sentiment that psychoactive substances like cannabis and psilocybin are harmless and in fact are good for mental health. I've had adverse mental reactions to both and I would caution people with family history of anxiety.
Eventually, he was so angry that he blanked out. He told me he found himself in a hyper lucid state, but in absolute darkness and in a state of pure dread.
He felt the presense of millions of dead egos that were "roaming" like zombies in this strange environment. Some were screaming like their skin was being pulled from their body, some were tormenting others. A total nighmarish trip.
He was so shocked by this experience that he stop smoking pot that very evening and never touched it again.