Yeah but it's anecdotal isn't it swedge. The fact is schizophrenia rates arn't exploding - which they definately would've done if cannabis was triggering it. You can't introduce a schizophrenia-causing drug to a population and go from no-one in the population using it 50 years ago to 5 or 10 million people using it heavily every day and not see a massive increase in schizophrenia rates. It simply isn't impossible.
How do you know diagnosis rates of schizophrenia wouldn't have fallen more if cannabis wasn't used recreationally?
