Personally had to call in the CATT guys (I think at the time this crew came from the Alfred in Melb) on a dear friend who had drug induced psychosis. Genetic predisposition to mental health issues does not mix with weed. Sure there are many many people who smoke weed for their whole lives with minimal psychological detriment but if someone has a family history of psychological issues - they're far more vulnerable...
Friend in question is now on heavy doses of medications and sees a psych once a week. Recovery is not likely so the current approach is symptom management and not treatment.
That being said - legalising weed (especially for medicinal purposes) is already far overdue.
