Which country comes to your mind with high usage of cannabis and not a crisis? Looks like the Netherlands (which came to my mind) has rather low cannabis use.

There also wouldn't be a statistic if people do not report to a doctor about 'hearing voices' for example.

Also the Netherlands has shown the increase in schizophrenia

https://www.who.int/substance_abuse/publications/cannabis_re...

For a deeper discussion see

https://theconversation.com/if-cannabis-is-getting-stronger-...