I reviewed the literature on the effects of marijuana for a school project a few years ago. What is remarkable is that one joint is actually less harmful than o

I reviewed the literature on the effects of marijuana for a school project a few years ago. What is remarkable is that one joint is actually less harmful than one cigarette, and that vaporizers and methods that don't involve inhaling smoke are basically risk-free. There are studies out there that have actually shown THC / cannabidiol to have slight anticarcinogenic effects, though that's all highly experimental (I think in a lab setting). The evidence for marijuana causing psychosis is extremely thin. Basically the strongest evidence out there are observational population studies (not controlled) that found there is a slight correlation between marijuana use and eventual development of psychosis. The obvious problem is that correlation != causation. It seems pretty reasonable to postulate that people who are mentally unstable are also more likely to try and seek solace/release in drugs.