Cannabis Facts December 10, 2013 Marijuana Does Not Cause Schizophrenia, Harvard Study Finds Zeke Becker A new Harvard study finds no evidence that marijuana causes schizophrenia. Categories: Best of the Web, Cannabis Facts, Marijuana News Tags: drug use, schizophrenia, study.By: Zeke Becker. Permalink: Shortlink: http://weedi.st/qu6N2