The joint you smoked last night won’t give you schizophrenia. It also won’t make you assault your neighbor.
You might not know that after reading a recent New Yorker article that draws connection between marijuana use, schizophrenia and violent crimes in Washington.
In the article — “Is Marijuana as Safe as We Think?” — writer Malcolm Gladwell focused on a 2017 report by the National Academy of Medicine that examined the scientific evidence of the health effects and therapeutic purposes of cannabis and cannabinoids. Gladwell’s article also draws on a new book by former New York Times reporter Alex Berenson called “Tell Your Children: The Truth about Marijuana, Mental Health and Violence.”
Gladwell’s article and a subsequent New York Times op-ed by Berenson, was quickly rebuked by marijuana researchers and legalization advocates, who took issue with Gladwell’s selective use of data and Berenson’s linking marijuana use to schizophrenia.
Beatriz Carlini, a senior research scientist at the University of Washington’s Alcohol and Drug Abuse Institute, said she was “disheartened” by the New Yorker article. Gladwell draws a connection between legal marijuana and an increase in crime, citing a 17 percent rise in aggravated assaults in Washington state from 2013 to 2017. The problem, Carlini said, is that there was a one-year decrease right before that, so after 2013 the numbers are just creeping back up to where they were before.
FBI data also estimate that, in every year between 2007 and 2017, Washington has had less violent crime per capita than the country as a whole. (Violent crimes are defined as aggravated assault, murder, non-negligent manslaughter, robbery and rape.) In 2017, for example, Washington had 304.5 violent-crime incidents per 100,000 people, compared with the national rate of 394 per 100,000 people.
The New York Times, in its data blog The Upshot, featured work by a University of Oregon economics professor whose model showed that Washington and Colorado had lower crime rates crime after recreational marijuana was legalized.
Carlini noted that other things were going on during that time — most notably, the privatization of liquor sales in 2012, which made alcohol easier to get in Washington.
“Alcohol has been linked to violence very clearly, although it is not the only factor,” Carlini said. “The same thing cannot be said about cannabis, except for this article.”
By highlighting certain parts of the National Academy of Medicine report and Berenson’s writings, Gladwell draws lines not only between marijuana and violent crime, but also between marijuana and schizophrenia.
Ziva Cooper, one of the authors of the National Academy of Medicine report, took issue with Berenson’s op-ed confusing correlation and causation.
Cooper, who is the research director at UCLA’s Cannabis Research Initiative, wrote in a series of Twitter posts that the Academy found an association between cannabis use and schizophrenia. Researchers also found an association between using cannabis and improved cognitive outcomes for people with psychotic disorders, which she points out wasn’t mentioned in Berenson’s piece.
“We did NOT conclude that cannabis causes schizophrenia,” she wrote.
“Since the report, we now know that genetic risk for schizophrenia predicts cannabis use, shedding some light on the potential direction of the association between cannabis use and schizophrenia.
“We also now know that under placebo-controlled conditions, (cannabidiol, or CBD) improves outcomes in patients with schizophrenia when given as an adjunct med, showing that cannabinoids (not necessarily cannabis) improve symptoms,” Cooper wrote.
Not everyone in the field of cannabis and cannabinoid research was put off by the articles. One of those was Denise Walker, whose position as a research associate professor at the School of Social Work at the University of Washington has her working in treatment and intervention for people with marijuana disorders.
Walker said that while Gladwell’s article wasn’t ideal, it does raise questions worth discussing, especially about the difficulty of studying marijuana.
“He was getting into some issues that need to be addressed and can’t be ignored,” Walker said.
The federal government classifies marijuana as a Schedule 1 controlled substance, the same category of drug as heroin. That makes marijuana hard for researchers to get their hands on; they can obtain it only from a federally sanctioned growing facility at the University of Mississippi. Walker said the government marijuana doesn’t reflect the high-potency kind used around the country.