In the article, Malcolm Gladwell drew connections between Washington's legal pot and its rates of violent crime. Gladwell was also criticized for implying pot use could cause schizophrenia, a conclusion counter to the research he cited.

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The joint you smoked last night isn’t going to give you schizophrenia. It also isn’t going to make you go out and assault your neighbor.

You might not know that after reading a recent New Yorker article drawing a connection between marijuana use, schizophrenia and violent crimes in Washington. The article — titled “Is Marijuana as Safe as We Think?” — sparked many an email thread and social-media critique by researchers of cannabis and cannabinoids.

Author 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 piece 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 piece, and a subsequent New York Times Op-Ed by Berenson, drew quick rebukes from marijuana researchers and legalization advocates, who took issue with Gladwell’s selective use of data and Berenson linking marijuana use to schizophrenia.

Beatriz Carlini, a senior research scientist at the University of Washington’s Alcohol & Drug Abuse Institute (ADAI), said she was “disheartened” by the article, which she and her colleagues have been discussing and emailing each other about since it was published earlier this month.

Gladwell draws a connection between legal marijuana and an increase in crime, citing a 17 percent rise in aggravated assaults in Washington state between 2013 and 2017. The problem, Carlini says, 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 saw 304.5 violent-crime incidents per 100,000 people, lower than the national rate of 394 per 100,000 people. Violent crime rates in our state and nationwide have both increased since 2014, and those recent numbers are still lower than in 2007-2009.

New York Times data blog The Upshot featured work by a University of Oregon economics professor whose model showed that Washington and Colorado had lower rates of crime after recreational marijuana was legalized.

Carlini points out that other things were going on during this same period — most notably, the privatization of liquor sales in 2012, which made alcohol easier to access 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 pot and violent crime but between pot and schizophrenia.

Ziva Cooper, one of the authors of the National Academy of Medicine report, took to Twitter to air her concerns with Berenson’s Op-Ed confusing correlation and causation.

Cooper, who is the research director at UCLA’s Cannabis Research Initiative, explained in a thread of tweets 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.

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 UW 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 pot hard for researchers to get their hands on; they can obtain it only from a federally sanctioned grow at the University of Mississippi. Walker said this government weed doesn’t reflect the high-potency kind actually being consumed around the country.

“As researchers, our hands have been tied when looking at the positive and negative effects of marijuana,” Walker said. “All the previous research very may well not apply because what people are using now is different.”