STUDY: Marijuana Does Not Cause Schizophrenia. “Marijuana may not cause schizophrenia, but it might be that people who are prone to developing schizophrenia are more likely to use marijuana. This would explain the link that’s been found in the studies.”

That said, “This study can’t tell us anything about the interaction between the genetic predisposition to develop schizophrenia and marijuana use. Many researchers still believe that marijuana use may be a factor in the onset of schizophrenia in those who are at risk. Certainly, there is plenty of other evidence out there that marijuana is not the totally safe drug that many teenagers perceive it to be.”