[_98fj]

> Or does cannabis just bring out an underlying psychosis that the person probably would have experienced anyway?

Leaving generic psychosis aside, when talking about schizophrenia this is a weird argument. Schizophrenia tends to worsen with every episode. It's of paramount importance to prevent any of them.

Having the first episode triggered by smoking cannabis with age 17 is worse than having the first episode brought on by a different cause with 25.

[Edit: I just realized I assumed causality here, which I have no proof for. But I do think that schizophrenic episodes are triggered by stressful thought-pattern and drug-use is one situation where those can occur.]