This fall, the city will distribute a "special cannabis variant" to a select group of mentally ill addicts.
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.
As Maia Szalavitz, a journalist specializing in public health and addiction, reported in 2010, a study by the National Institute of Health and Medical Research in France "identified two broad groups of people with schizophrenia who used cannabis: those whose disease was profoundly affected by their drug use and those who were not."
The research that's been conducted to date suggests that people who suffer from or are predisposed to psychosis simply shouldn't use marijuana. Utrecht's study will be conducted under a different paradigm.
This fall, the city will distribute a "special cannabis variant" to a select group of mentally ill cannabis addicts—those suffering from a combination of anxiety, "psychotic attacks," and insomnia. This pot variant (more commonly referred to as a "strain" in the U.S.) is said to "dampen instead of provoke" the above combination of symptoms. The marijuana will come from the Office of Medicinal Cannabis, which is housed in the Dutch Ministry of Health, and the study will be conducted by Dutch addiction treatment centers Altrecht and Victas, and monitored by the Amsterdam Medical Center.