Myths About Marijuana: Intoxicating But Untrue

Richard Kirk was a nice Mormon suburbanite with three sons. Kirk seemed eminently respectable, until the day he flipped out and murdered his wife right in front of the children. Kevin Lee Lyons, also a father of three, had no criminal record until the afternoon when he likewise shot his wife, and then viciously murdered a neighbor. Raina Thaiday was once a mother of seven. That was until she stabbed them all to death, along with a niece who was staying with the family at the time. She is now in a mental institution in Brisbane, Australia.

These are just a few of the stories you will find in Alex Berenson’s stark Tell Your Children: The Truth About Marijuana, Mental Illness, and Violence. A former New York Times reporter, Berenson is now on a quest to inform the public about the darker side of pot.

The central thesis of his book is simple: Exposing the brain to Tetrahydrocannabinol (THC), the primary psychoactive component of marijuana, greatly increases a person’s susceptibility to mental illness. This is particularly true for adolescents and young adults, but even older adults may pay a serious price for tinkering with their endocannabinoid system.

Increasing mental illness means increasing violence, because delusional and paranoid people commit far more than their share of violent crimes. The situation has worsened in recent years, not only because legalization increases recreational pot use, but also because legal markets develop dramatically more potent strains than were previously available.

Today’s marijuana addicts are consuming quantities of THC that would have been utterly unattainable for their Woodstock-attending forebears. Compared to the pot that was smoked in the 1970s and before, a typical joint today contains 10 to 20 times more THC, and that’s even before we consider the effects of oils and edibles, into which THC can be infused in potent amounts.

In short, America’s embrace of legal pot is becoming a social catastrophe. If Berenson is right, it’s only going to get worse.

Almost his entire book is devoted to raising the alarm. Very little is said about prudent drug policy, or thorny issues of moral responsibility. Berenson isn’t doing moral philosophy here. He just wants to convince you that pot is seriously dangerous. To that end, he combines grisly anecdotes with a whole lot of numbers, painting a genuinely disturbing picture. Pot may ruin your life, or even kill you—or (see above) someone you love.

This reviewer found the warnings convincing; nevertheless, in the interests of fairness, let’s start by acknowledging the weakest points of Tell Your Children. Scientists don’t understand exactly how cannabis affects the brain. We know that THC affects the endocannabinoid system, which plays an important role in regulating stress, appetite, memory, and motivation. But the science is underdeveloped here, so we don’t know exactly how it all works. Marijuana is still a Schedule One drug in the United States, meaning that the Food and Drug Administration considers it to have little or no medicinal value, and a high potential for abuse. Schedule One drugs are subject to serious restrictions, so randomized, controlled studies are few and far between. Berenson mostly has to rely on observational and natural studies, and on data tracking the correlation between marijuana use and other negative outcomes.

The Problem of Induction

Correlation does not equal causation. Since Berenson’s case relies heavily on correlation, his critics have accused him of missing this basic principle. That’s unfair. Berenson doesn’t need a tutorial in the problem of induction; he himself explains why some of the studies he cites have better data than others, and he gives space to different causal theories, like the theory that people susceptible to mental illness may also be susceptible to drug abuse, possibly as an attempt at self-medication. In the end, though, he considers the correlations between pot and mental illness so strong as to make causal explanations overwhelmingly the most plausible.

The pile of data really is fairly overwhelming, spanning different age groups, ethnic groups, and regions of the globe. One of the groundbreaking studies Berenson cites is from Sweden; another comes from New Zealand. British researchers have done significant work on the subject. Legalization advocates like to give the impression that resistance to pot is a distinctively American (possibly xenophobic or racist) phenomenon. Berenson suggests that in reality, North America is becoming the pot capital of the world even as other countries are developing more sensible drug policies.

Marijuana users are significantly more likely to have psychotic breaks, and to become schizophrenic. Even after controlling for other known risk factors (such as a family history of mental illness), adolescent cannabis use seems to at least double a person’s lifetime risk of being diagnosed with schizophrenia. Many who experience temporary marijuana-induced psychosis will go on in a matter of years to be diagnosed with schizophrenia; not surprisingly, this is especially likely to happen if the person continues to use marijuana. For those who are already mentally ill, marijuana use seems to worsen symptoms, and to diminish the effectiveness of treatment. In mental institutions, Berenson claims, patients who abuse marijuana are likelier to commit acts of violence than those who abuse alcohol.

Might marijuana have at least some beneficial effects, particularly on those who might otherwise choose a more dangerous drug? This has been a popular argument among legalization advocates in the wake of the opioid crisis, and of course there may be particular cases that support the theory. In general, though, Berenson argues that pot is likelier to be a gateway drug, not an off-ramp from drug addiction. Insofar as studies have shown otherwise, he claims, their conclusions are based on a limited (and dated) data set that primarily reflects divergent geographical patterns in the prevalence of two drugs, marijuana and opioids.

The American push for marijuana legalization was originally a phenomenon of the western United States. The opioid epidemic first hit well to the east of the Rocky Mountains, in places like Ohio and surrounding states. For a time, then, marijuana use happened to be high in places where opioid abuse was relatively low. As both epidemics spread, however, that distinction vanished. It has long been known that pot users are much likelier to go on to abuse cocaine, but Berenson claims that they are also at greater risk of opioid addiction. Pot isn’t going to save us from heroin, he argues, basing himself on recent data.

The book’s final section, on marijuana and violence, is the most disturbing but also the most speculative. Here Berenson cites some serious studies, but also spends a lot of time combing through arrest reports and social media feeds, looking for anecdotal evidence of pot use on the part of violent offenders. That might make sense, if indeed there is an elephant in the room that the public refuses to see. Or, it could just be an exercise in confirmation bias. In any event, Berenson freely admits that there’s a lot we don’t know.

Here’s something we do know, though: It’s common for psychosis to contribute to appalling acts of violence. Schizophrenics probably don’t represent much more than 1 percent of the population, but in most years they are responsible for at least 5 to 10 percent of homicides. People who hear voices aren’t always dangerous, but the voices in your head have been known to give bad advice. How does marijuana factor in? If it can induce psychosis, and psychosis can induce violence, then it seems likely that increased marijuana use will correlate with increased violence. According to Berenson, that is indeed what the data show.

Why Whistle Past the Graveyard?

Unsurprisingly, Tell Your Children has generated considerable controversy, with legalization advocates loudly complaining that it is paranoid and wildly overblown. The issue is so heavily politicized that it’s difficult to get an unbiased perspective, and it’s clear enough that Berenson is an activist. Yet he leaves one thinking, even if the case is somewhat less grim than he says, shouldn’t we still be worried?

Let’s assume for the sake of argument that Berenson did cherry-pick the most gruesome stories, and that he devotes disproportionate attention to the most damning studies. It still adds up to a lot of sobering data. The dominant narrative of our time suggests that marijuana is a mostly harmless drug whose primary side effects are of the “hungry, happy, sleepy” variety.  That’s whistling past the graveyard. After reading Berenson’s book, this parent immediately took the title advice and spelled out all the reasons why her children would never come home with that sickly sweet smell on their clothes. (I went to high school in Boulder, Colorado. My nose knows.) It’s hard to imagine that other parents wouldn’t do the same, as opposed to flipping the book into the round file with a confident, “Correlation doesn’t equal causation!”

There’s no denying that crafting good drug policy is hard. This is a substance that’s easy to grow, and the effort to control its production and distribution can precipitate clogged courts, aggressive police, and complaints about racial disparities in enforcement. Also, it can be difficult to get people to opt for treatment when they know they’re breaking the law just by using a drug. Going with a softer approach—such as the moderate decriminalization scheme that is in place in Portugal—does not necessarily avoid these effects, even as it can add other disadvantages, namely fueling black markets and funding crime syndicates. Full legalization, Berenson is right to point out, means that a drug will be readily available in ever-more-potent strains, even as it infiltrates mainstream culture to an extent that almost certainly wouldn’t be possible if recreational use were not legal. There’s really no happy solution here. We have to pick our poison.

What we don’t have to do is lie to the public. Marijuana is dangerous, and the public needs to know that. It’s especially dangerous to people in their mid-twenties or younger, but even for people above that range, it can cause mental instability. It is not God’s greatest gift to medicine, and all of the associated risks have grown far more severe over the past couple of decades as commercial markets amp up the THC in available strains. Regular users can become violent, and that violence is likeliest to be inflicted on intimates. The idea that pot might offer a safe recreational alternative to alcohol is understandably intoxicating. Unfortunately, it isn’t true.

The legalizers have already made their mark, and Americans will continue to wrestle with the consequences over the next several decades. At the very least, you can make sure your own kids know what can happen to their brain on drugs. Mine have been told.