[trevwilson]

> The only answer which can be given with any certainty at this point is "we don't know"

It might be a little more convincing if you shared whatever studies you're referencing to form this opinion, because while I don't have access to the paper linked above the abstract pretty definitively seems to be saying that we do know with some certainty:

> Evidence reviewed here suggests that cannabis does not in itself cause a psychosis disorder. Rather, the evidence leads us to conclude that both early use and heavy use of cannabis are more likely in individuals with a vulnerability to psychosis.

>Future research studies that focus exclusively on the cannabis-psychosis association will therefore be of little value in our quest to better understand psychosis and how and why it occurs.

[arp242]

The full text is on Sci-Hub; I won't link to it here directly (I'm not sure if it's allowed?) but it's the first result in popular search engines for me.

Wikipedia has a decent overview of the available literature; when I looked at it last year I found it fairly comprehensive and balanced: https://en.wikipedia.org/wiki/Long-term_effects_of_cannabis#...