Study Suggests Link Between Schizophrenia, Cannabis

A new study out of Denmark shows a link between increased cases of schizophrenia and cannabis use disorder. The study, published in JAMA Psychiatry, notes that both the use and potency of cannabis have gone up in the last 20 years. Cannabis use disorder is not the mere use of the drug, but a pattern of behavior that could include using too much even when there are negative consequences, or difficulty stopping use, per CNN. The study says cases of cannabis use disorder are going up, and it’s turning up in people diagnosed with schizophrenia. “There is, unfortunately, evidence to suggest that cannabis is increasingly seen as a somewhat harmless substance, Carsten Hjorthoj, one of the study’s authors, said.

Other researchers have suggested a link between use of cannabis and risk of schizophrenia. This study says schizophrenia cases have gone up in Denmark. The study used data from people who had already been diagnosed with cannabis use disorder—not people who use the drug more occasionally—and tracked who was diagnosed with schizophrenia, too. "Cannabis use disorder is not responsible for most schizophrenia cases, but it is responsible for a nonnegligible and increasing proportion, Tyler J. VanderWeele, a Harvard professor, wrote in a commentary accompanying the study. (More cannabis stories.)