Long time lurker here. Not sure if this helps the discussion but have actual first hand experience with this. I was a heavy user of marijuana (extremely heavy I would say) from my late 20s to my early 30s. One day in those 30s (combined with significant physical effort that day and heat) smoking my umpteenth spliff of the day led to a complete blackout on a public sidewalk. From that point I began experiencing persistent auditory hallucinations and was eventually diagnosed as schizoaffective. I had no prior expression of schizophrenia and no family history that I am aware of (though there are clearly other family members with some psychological disorders). It is roughly 4 years since the last time I touched marijuana and the auditory hallucinations persist. Still in favor of legalization, but, as with overconsumption of practically anything, it should probably come with clear awareness of the risks involved.