Regular use leading to psychosis doesn't sound too awful on paper until you hear what that means in reality.
A true story. I knew an attractive, intelligent young woman in her late twenties, a friend of one of my former housemates. Her gradual heavier use of cannabis led her down a very sad path. First estranging herself from her family, then slowly one by one shedding off her friends into total social isolation. Then she beat her wonderfully loyal and playful dog so much that it at one point ran away. Police brought it back. When it finally bit her during the next beating, she had it put to sleep. To this day I don't understand why she didn't simply give it away or why a vet would kill a perfectly healthy animal as it should have been clear it was the owner, not the dog who was ill.
Her psychosis got worse. One evening she turned up at our place at around midnight and forced herself into the house even though her friend no longer lived there. Sat on the sofa mumbling to herself. It took a friend and me until 3 am to slowly persuade her to leave. When we informed her parents the next day they said they could do nothing. Even after my friend and I had offered to make a false statement of threatening behaviour to the police so that she at least could be committed and get some rest. But there was not much point in us taking this risk if there was no follow-up.
The next day I went on my then scheduled holiday. When I returned two weeks later there was a black-rimmed envelope in my postbox. Three days after the incident she had undressed, folded her clothes in a neat pile, placed them at the bottom steps of the public stairwell of the apartment she was living in, put her passport on top, walked 8 stories up the stairs stark naked and threw herself down the rubbish shute ending in a closed steel container on the ground floor. By chance, a janitor found her body the next day.
I'm from Amsterdam NL and up until that point, I too held the much-shared liberal standpoint that cannabis is mostly harmless .... until it's not.
