This doesn’t change my opinion on legalization or drug policy but I try to not ignore data points that are contrary to my currently held beliefs.
> Several studies have linked marijuana use to increased risk for psychiatric disorders, including psychosis (schizophrenia), depression, anxiety, and substance use disorders, but whether and to what extent it actually causes these conditions is not always easy to determine. Recent research suggests that smoking high-potency marijuana every day could increase the chances of developing psychosis by nearly five times compared to people who have never used marijuana. The amount of drug used, the age at first use, and genetic vulnerability have all been shown to influence this relationship. The strongest evidence to date concerns links between marijuana use and psychiatric disorders in those with a preexisting genetic or other vulnerability.
https://nida.nih.gov/publications/research-reports/marijuana...
Do not buy pretty much anything else in the article. Schizophrenia is not caused by marijuana and the correlation there is likely Schizophrenics self medicating. Very unlikely there's a causative link there. Although I'd buy that THC is a poor choice of medicine for Schizophrenics and that there might be some exacerbation going on.