From my short 1 month experiene working in a clinical ward: if young people got brought in due to a psychosis, in the case that it was drug induced, at least 50% were long term cannabis users (followed by alcohol abuse, then some psychoactive drugs, and heroin/crack).
Cannabis definitely is not the vanilla drug so many people make it out to be.
*EDIT: I get the selection bias now, sorry.
To all of you: thank you so much and a very merry christmas! I hope you are doing fine.