The schizophrenia link has been a scare story for at least two decades now but why can't any research establish or discredit it?
ETA: Andrew Huberman did a podcast with Dr. Matthew Hill (a researcher in Canada) that covers a lot of the most recent days and studies
https://www.cambridge.org/core/journals/psychological-medici...
THC dyregulates glutamate transmission and it is probably responsible for hallucination (positive symptoms) in schizophrenia.
As a result, if you have a family history of schizophrenia, you'd be better off abstaining.
The scare story bit was that just because there was a real link found in people who were genetically predisposed to develop schizophrenia, the same level of danger applied to everyone else.
More complex than the simple idea that cannabis will give you schizophrenia. But people prefer simplistic ideas over complex ones. Similar to how "smoking gives you cancer" where in reality it continually increases the chance of developing cancer, treatable or terminal, with persistent usage.
It is also widely claimed that LSD has a much stronger association with schizophrenia than weed, so if weed only has this sometimes (e.g. never when it's self-grown) that may explain why it's hard to pin down a link.
Hidden confounding variable that may change at any point but only in a subset of your study group.
albert hoffman began his famous golden bicycle ride after what he presumed to be crossover from a cigarette.
a potent artificial sweetener was discovered this way.
And was given to me as a reason why the edibles I had tried that one time made me hallucinate that everything was blue.
I ran a very vague "dab olympics" comp once at a festival. It was in the early days of dabbing becoming a thing. Someone gave us an ouce or so of the stuff and we did out doses about as thick as a piece of string and about an inch long. Turns out that's a monumental dose of thc.
The rules of the comp were, come have a dab then come back and tell us about your experience. Have another and do the same on day 2. We picked the winner off who enjoyed it the most/actually remembered to come back for a yarn ans so on. Gave away a 200 buck dab rig. Free entry.
The amount of folks who hadn't consumed cannabis before and came back with stories of the most visual hallucinations and body trip experiences was pretty surprising. Turns out we send a few folks who were regular lsd consumers off to the moon and back. Woops. No injuries, was a pretty fun weekend. Sample size of about 30 lol.