The City of Utrecht Wants to Convince Mentally Ill Marijuana Users to Smoke Better Pot

Thanks in part to the Netherlands' policy of marijuana decriminalization, there are people living in the Dutch city of Utrecht whose addiction to cannabis prevents them from getting effective treatment for mental illness. According to a September 10 statement from Utrecht Mayor Aalt Wolfsen, "There is a group of about eighty people with a chronic psychotic disorder who barely respond to their treatment. A possible explanation for this is their severe dependence [on] cannabis."

Wolfsen's hedging—saying that marijuana addiction is a "possible explanation," rather than a certain one—reflects what we currently know about marijuana and mental illness. While various studies have explored the link between cannabis and psychosis, particularly schizophrenia, there's a lot we still don't know. Research has shown that marijuana can trigger schizophrenia in people who are genetically predisposed to the illness, and exacerbate it in people who are already suffering from it, but even those findings aren't airtight.