Subscribe to Entrepreneur for $5

There's No Connection Between Marijuana And Violence, Experts Say

A new book claims otherwise, but experts say there is not a connection between the two.

Opinions expressed by Entrepreneur contributors are their own.

Marijuana and violence have been getting connected in odd ways over the past month or so. A new book argues that there is a connection, and a famous TV host has also raised the issue. Experts, on the other hand, have lined up to argue that they are both wrong.

vzwer | Getty Images

The latest controversy over marijuana and violence got kickstarted by FOX News host Tucker Carlson when he recently interviewed former New York Times reporter Alex Berenson.

Speaking about the mass shooter in Dayton, Ohio, Carlson said the young man was "known to be a long-time user of marijuana. It turns out, in fact, that many violent individuals have been avid marijuana users. Is there a connection?"

Related: Marijuana Labs Adding Tests Targeting Vitamin E Acetate In Response To Vaping Health Scare

Studies Don't Support A Connection

The fact that Carlson brought this up is no surprise. Berenson has a book — called "Tell Your Children: The Truth About Marijuana, Mental Illness, and Violence" — that (if the title isn't obvious enough) makes the connection between marijuana and violence.

His book essentially argues that marijuana use leads to psychosis, and that psychosis is connected with violent behavior. Carlson offered no pushback on Berenson's book, according to PolitiFact. Rather, he praised the former reporter as a "voice in the wilderness."

Is he? Science suggestions the answer is "no."

Katherine Newman, University of Massachusetts interim chancellor and author of a book on school shootings, told PolitiFact that the idea of marijuana use leading to violence is "absolute nonsense. There is no link whatsoever between marijuana and extreme violence."

She's far from alone. Scientists and clinicians wrote a public letter earlier this year that blasted Berenson's book. Among their assertions is that the author attributed cause to mere association, cherry picked data and suffered from selection bias.

"In addition to his flawed use of science, Berenson's argument outright ignores most of the harms of prohibition, focusing narrowly on the harms of marijuana use," the letter stated. While acknowledging that "none would argue that marijuana is risk-free" they wrote that prohibition led to the "criminalization of millions of people, overwhelmingly black and brown."

They wrote: "Legalization is the less harmful approach."

Related: Nominate Your Favorite Budtender for Our Annual Best Budtenders List

A British And Dutch Study IS Often Used As Source Material

British and Dutch researchers published a study that found marijuana increased violent behavior, but that involved people who already suffered from psychotic disorders such as schizophrenia.

Even given that context, the researchers wrote this: "It is unclear to what extent different categories of illicit substances, as defined by their psychopharmacological effects, are related to violent behavior."

Even one of the authors of the study used by Berenson in the book, Ziva Copper, the head of UCLA's Cannabis Research Initiative, Tweeted that the study was not as conclusive as Berenson's book suggested.

She wrote that the study found an association between marijuana and psychosis, but not that marijuana causes psychosis.

Follow on Twitter to stay up to date on the latest cannabis news.