Fortunately, it's still illegal to even study these things in America so we can comfortably resort to what we have faith in without the scourge of proof.
This goes just as much for the miracle of CBD oil (CBD rhymes with 'znake').
There are estimates that 60-90% of schizophrenics smoke cigarettes, which is 2-3x the normal smoking rate. I think schizophrenics are more likely to smoke marijuana around the time the disease begins to manifest. It's a lot easier to look at your child/brother/uncle/whatever and say "weed did this to him, it's all weed's fault" vs "the disease presented concurrent with a time period where person used cannabis".
I'm not even slightly convinced that weed induced schizophrenia is real.
All I really mean by the comment is that I ask the possibility be considered to be real.
Not only that, I lack the confidence we as a society can make adequate decisions on restrictions to freedoms based on the sorts of numbers and correlations that are currently being published. Does the expected reduction in harm justify the restrictions of personal freedoms imposed in its name? Does it help more than, say, banning high school sports would?