As someone who does have schizophrenia and did smoke weed heavily (once a day, an eighth a week), I support its legalization with the caveat that people should be screened for its use and people with likely predisposition for schizophrenia should avoid it, and if Big Pharma (which I hate) wants to develop a version which lowers the likelihood of developing schizophrenia (which I do not believe is likely), I'm all for it. I would not say marijuana use caused schizophrenia in my case, there's a possibility that I would've developed schizophrenia later in life when I had a career, and it might've been worse for me, or might have been better.
I'd also like to add that stimulants, alcohol, and psychedelics are some other classes of drugs to avoid, if you feel you are predisposed to schizophrenia.
I'd also like to add that stimulants, alcohol, and psychedelics are some other classes of drugs to avoid, if you feel you are predisposed to schizophrenia.