Hi There, There was a documentary on CBC's "The Nature of Things" in Canada (called 'The Downside of High') about marijuana use and schizophrenia. A major point was that there are two chemicals in marijuana, THC and cannabidiol. THC triggered and exacerbated schizophrenia in young people with a certain gene code. Cannabidiol, however, was shown to have neuro and immune protective properties. The street marijuana sold nowadays tends to be very high in THC and low in cannabidiol, so it can have a bad effect on neurological and psychiatric issues, or be a trigger in some people. Here is an article about the documentary: http://hearingvoicesnetworkanz.word...documentary-lights-up-potschizophrenia-links/ The documentary follows three young people who had very serious psychiatric problems, which they trace directly to marijuana use. It is quite sad to see how their lives have been set off track by a drug that for others has no serious side effects. It's all in the genes, like so many things.