Possible Pot Side Effect: Psychosis
It's looking more and more like cannabis causes psychosis, and not the other way around. In other words, generally speaking a person doesn't use cannabis because she or he is psychotic, but that person can develop symptoms of psychosis because of using, particularly when they are young. This is really important to share with your kids, especially at a time when legalization of marijuana might suggest to them that cannabis is completely safe.
Trust me when I say that for most kids, the fear of becoming psychotic outweighs the curiosity or desire to use marijuana. The key is to let them know about this link so that they can make smarter choices for their developing brains.
Check out this article that covers the most recent study.