Cannabis plants grow in a greenhouse at the CannTrust Holdings Niagara Perpetual Harvest facility in Pelham, Ontario. (Cole Burston/Bloomberg)

In January 2019, Alex Berenson, a novelist and former New York Times reporter, released “Tell Your Children: The Truth About Marijuana, Mental Illness, and Violence.” The book suggested heavy marijuana use could trigger psychosis and increase violent behavior — effects Berenson claimed Big Marijuana didn’t want users to know.

The book marked the return of Reefer Madness, the sensationalistic warning that marijuana use will result in insanity. “Tell Your Children,” a deliberate reference to the original title of the 1936 film “Reefer Madness,” received positive coverage from the New Yorker and Mother Jones for what some called its troubling truths. Yet other outlets, including the Rand Corp., the New Republic and Drug Policy Alliance, argued that Berenson was using junk science. And the book re-energized debate over what many have claimed is cannabis’s inevitable march toward national legalization.

"Tell Your Children” reignites a long-held concern about cannabis’s public safety. But in relying on sensationalism over science, it has become just the latest use of alarmist claims and attention-seeking to upend a serious public policy dialogue. As a result, rather than contributing to a meaningful discussion about pot and its public health consequences, good and bad, “Tell Your Children” provokes emotional outcry rather than a rational debate on the issue.

“Tell Your Children” isn’t alone. Both supporters and opponents of legalization are quick to use sensationalism to prove their points, stunting the pursuit of real research needed to determine cannabis’ social effects.

Berenson’s book focuses on the health effects of marijuana, particularly on mental health. He argues that, as increasingly potent cannabis is more widely available, problems with psychosis and mental illness will increase. He also claims that “Big Marijuana,” which includes legalization advocates like the Drug Policy Alliance and the Marijuana Policy Project, downplay the negative effects of the drug’s use and argue instead that the real harm from cannabis come from the laws against it.

In making those arguments, Berenson draws a parallel to the cigarette industry and the persuasive propaganda Big Tobacco put forward in the 1950s, ‘60s and ‘70s. In the mid-20th century, Big Tobacco was engaged in a commercial, cultural and scientific battle to convince the medical establishment and public that its product was healthful and therefore innocuous. This message became increasingly difficult to sustain, however, as smokers grew ill in greater numbers.

But rather than admit defeat, the industry employed scientific research to change the conversation. It pointed its finger at genetics or social factors as the primary causes of tobacco-related ailments, rather than tobacco per se.

These hazy obfuscations worked for a while, but ultimately, because nicotine is a legal substance and can be studied with relative ease, real scientific data was collected showing the clear connection between nicotine use and the development of certain forms of cancer. Despite the efforts of the tobacco industry to manipulate the data, the truth came out, and it hurt business. Cigarette consumption rates have fallen, from 42 percent of adults in 1965, to just 14 percent of adults today.

The science behind marijuana is different, however. Because the federal government believes the drug has no medical value and a high potential for abuse, it’s difficult to gather concrete scientific data on cannabis’ effects. For example, the Drug Enforcement Administration requires researchers to keep cannabis in an alarm-controlled, locked container that is physically attached to a floor or wall. The government will not accept foreign studies of the drug’s effects. And, without purchasing the drug on the black or white market, it’s hard to access enough samples of the federally approved substance to do blind studies.

Still, that hasn’t prevented the same kinds of major claims that surrounded cigarettes from invading the supposedly objective science around cannabis, both for and against the drug.

Some have advised caution. In 1968, articles in the American Journal of Psychiatry and Psychiatric News asserted the dangers of pot. The writers disapproved of its use because a shortage of evidence would not allow for an informed decision of the drug’s hazards. These publications also suggested there was already enough evidence underpinning its dangers. Some physicians went further, commenting: “Our purpose is to establish scientific proof of marihuana’s ill effects.”

Others disagreed. Stanley Yolles, director of the National Institute of Mental Health, testified to the Senate Judiciary Subcommittee on Juvenile Delinquency in 1969 about marijuana’s negligible medical dangers. The same year he wrote an article for The Washington Post entitled “Pot Is Painted Too Black,” Yolles argued that scientific and medical facts were totally disregarded when it came to marijuana laws. “I know of no clearer instance in which the punishment for an infraction of the law is more harmful than the crime,” he said.

A half-century later, it’s obvious we still need to enhance the “evidence about evidence” when it comes to drugs, science and policy. Because without it, we are left grasping at the few studies that do emerge, including sensationalist works like Berenson’s. The result? Fearmongering and uncertainty, rather than science, triumphs.

For Alan Leshner, former head of the National Institute of Drug Abuse and onetime member of the U.S. National Science Board, “there is a unique disconnect between the scientific facts and the public’s perception about drug abuse and addiction.” Or, as the British psychopharmacologist David Nutt has put it, emphasis ought to be placed on “evidence, not exaggeration.”

It’s valuable to think critically about the rise of Big Marijuana, consumerism and public health. We have not reached firm determinations about the safety and efficacy of cannabis. The basic science and addiction studies are nowhere near definitive. Not surprisingly, those in the cannabis industry want us to believe it isn’t harmful and it ought to be considered a therapy or medicine; they will profit from its sale. And writers like Berenson want us to believe the drug is deeply harmful and problematic, for book sales if nothing else.

Until we have real, concrete evidence — like the statistics that pulled the rug out from Big Tobacco’s 50-year-old campaign — we will be left with sensationalism and little else. This is no way to develop public policy, no matter how trendy the ideas may seem.