David L. Nathan, MD

Many have said that truth is the first casualty of war. In the war on drugs, truth died before the first shot was fired. In the US, cannabis prohibition began in 1937 after several years of anti-narcotic propaganda. The intellectual low point of the campaign came in 1936, when the notorious exploitation film 

. This also happens to be the name of fiction writer and former journalist Alex Berenson’s new book. Nowhere in his book does he acknowledge his title’s irony, yet Berenson’s reference to 

 is appropriate: Like the movie, his book is ripe with hyperbolic assertions and biased interpretation of scientific literature.

Berenson claims that cannabis use leads to psychosis and violence. He states his thesis just a few pages into the book, claiming that “whether marijuana is dangerous to the brain and can ultimately cause violence is a scientific question, with a hard yes or no answer. We have that answer.”

This absurd promise is the fatal flaw of Berenson’s book. To date, research has not demonstrated a simple connection-let alone a causal connection-between cannabis and violence.

A disclosure: We are physicians who support the legalization and effective regulation of cannabis, based on principles of public health and social justice. We strive to follow the science, even when the science contradicts our conclusion that the harms of cannabis prohibition are far worse than the harms of cannabis use.

In that spirit, we acknowledge one key point of agreement with Berenson: Research does show that cannabis can trigger or worsen psychosis in predisposed individuals. Indeed, we have spent years educating the public about this risk.

But most of Berenson’s assertions are unsupported by science. For example, a recent study showed a decrease in domestic violence among cannabis-using couples. This doesn’t prove that cannabis reduces violence, but it certainly suggests that any relationship between cannabis and violence is complicated and influenced by a host of factors. Berenson conveniently dismisses studies like this that are in conflict with his narrative.

Reaction to the book has been swift. Dr Ziva Cooper, a co-author of the 2017 National Academy of Medicine report on cannabis upon which Berenson relies, tweeted: “[W]e did NOT conclude that cannabis causes schizophrenia.” RAND Drug Policy Research Center co-director Dr Beau Kilmer was unequivocal in a recent tweet about RAND’s interpretation of the literature from 2001 to 2011: “Marijuana use does not induce violent crime.”

 has nothing to do with cannabis. Berenson’s insidious association of psychosis with violence unfairly stereotypes people living with psychosis, very few of whom are ever violent, evoking the bias that has long plagued this vulnerable population.

Lest we be misunderstood, we’re not claiming cannabis use is risk-free, but we believe the book is a distraction from a serious discussion of the other risks of cannabis use. Studies show that you shouldn’t drive a car while under the influence, that underage recreational use is harmful, and that some people use cannabis problematically. However, cannabis use causes no lasting harm to most healthy, non-pregnant adults.

Berenson discusses cannabis as if it were uniquely dangerous. Many foods, drugs, and activities like motorcycle riding carry a risk of injury or death to people who indulge in them. As Alcohol Prohibition taught us, the government must not lightly wield the blunt instrument of criminal justice to stop consenting adults from engaging in risky behaviors.

Prohibition has not solved any problems of cannabis use, despite more arrests annually for cannabis possession than for all violent crimes combined. In fact, it is a failure of historic proportions, documented in the government’s own statistics.

Here is where we get into why we believe cannabis prohibition creates more harm than cannabis use: Black people are almost four times more likely to be arrested for cannabis possession than whites despite the fact that black people and white people use cannabis at roughly the same rate. This racial disparity worsens the economic plight of already struggling communities of color. The resulting poverty limits access to education, jobs, rehabilitation, and health care.

That is only one of the ways cannabis prohibition undermines public health. With underage use increasing from the 1960s until legalization began, prohibition has failed in its most basic intent, which was to prevent access to minors.

But far from the apocalyptic predictions of opponents of legalization, underage cannabis use has not increased in states that have legalized cannabis. We are not surprised. Regulation prevents youth access at licensed retailers-who check for ID-and creates a legal distinction between underage and adult use that minors can understand and respect.

We appeal to government officials, the public, and our fellow physicians to support the sensible regulation of adult cannabis use as a more humane and cost-effective alternative to prohibition. Our nation must embrace science, reject misguided moralism around cannabis use, and recognize that books like Berenson’s are exactly what he inadvertently entitled his own: 

 received a number of “letters to the editor” in response to the front-page commentary in the April issue, “21st Century Reefer Madness.” Briefly, two primary issues were recurrent in many of these letters: (1) questions about potential conflicts of interest by the authors, and (2) a perceived minimization of the well-established increased risk of psychosis in children, adolescents, and young adults who use and abuse cannabis.

I intentionally wrote an accompanying editorial in the same issue (April 2019, pages 8-9) to briefly review the extensive published literature that exists related to cannabis, including its documented risks and benefits, along with the associated references. That editorial can be read 

Regarding the question of conflict of interest, Nathan and colleagues acknowledged in their article that they all served as board members on the organization Doctors for Cannabis Regulation (

 subsequently contacted the authors to inquire about any financial conflicts related to their board membership on DFCR. The authors replied with the following additional information:

“Membership in DFCR does not offer any financial incentives. Our physicians work on a volunteer basis, and we often use our own money to subsidize our advocacy.  As I [David L. Nathan, MD, DFAPA; President, Board of Directors] previously disclosed, I am a consultant to governments, nonprofits, and industry on cannabis health and regulatory issues. Other spokespeople do as well.”

Moreover, the authors stated that: “From 2016-2018, DFCR received 11% of its income from the cannabis industry.”

The letters already received, and all subsequent letters to the editor related to this article will be posted below.

 is an honorary board member of Doctors for Cannabis Regulation (DFCR.org), which is the first and only national physicians’ association dedicated to the legalization and effective regulation of cannabis in the United States. 

From 2016-2018, DFCR received 11% of its income from the cannabis industry.

The authors report no conflicts of interest concerning the subject matter of this article. 

Articles

Many have said that truth is the first casualty of war. In the war on drugs, truth died before the first shot was fired.

Author | David L. Nathan, MD

Articles

21st Century Reefer Madness