Marijuana, Mental Illness, and Violence
Alex BerensonAuthor,
Tell Your Children: The Truth About Marijuana, Mental Illness, and Violence
Alex Berenson
is a graduate of Yale University with degrees in history and economics.
He began his career in journalism in 1994 as a business reporter for
the
Denver Post, joined the financial news website TheStreet.com in 1996, and worked as an investigative reporter for
The New York Times from 1999 to 2010, during which time he also served two stints as an Iraq War correspondent. In 2006 he published
The Faithful Spy,
which won the 2007 Edgar Award for best first novel from the Mystery
Writers of America. He has published ten additional novels and two nonfiction books,
The Number: How the Drive for Quarterly Earnings Corrupted Wall Street and Corporate America and
Tell Your Children: The Truth About Marijuana, Mental Illness, and Violence.
The following is adapted from a speech delivered on January
15, 2019, at Hillsdale College’s Allan P. Kirby, Jr. Center for
Constitutional Studies and Citizenship in Washington, D.C.
Seventy miles northwest of New York City is a hospital that looks
like a prison, its drab brick buildings wrapped in layers of fencing and
barbed wire. This grim facility is called the Mid-Hudson Forensic
Psychiatric Institute. It’s one of three places the state of New York
sends the criminally mentally ill—defendants judged not guilty by reason
of insanity.
Until recently, my wife Jackie—Dr. Jacqueline Berenson—was a senior
psychiatrist there. Many of Mid-Hudson’s 300 patients are killers and
arsonists. At least one is a cannibal. Most have been diagnosed with
psychotic disorders like schizophrenia that provoked them to violence
against family members or strangers.
A couple of years ago, Jackie was telling me about a patient. In passing, she said something like,
Of course he’d been smoking pot his whole life.
Of course? I said.
Yes, they all smoke.
So marijuana causes schizophrenia?
I was surprised, to say the least. I tended to be a libertarian on
drugs. Years before, I’d covered the pharmaceutical industry for
The New York Times.
I was aware of the claims about marijuana as medicine, and I’d watched
the slow spread of legalized cannabis without much interest.
Jackie would have been within her rights to say,
I know what I’m talking about, unlike you. Instead she offered something neutral like,
I think that’s what the big studies say. You should read them.
So I did. The big studies, the little ones, and all the rest. I read
everything I could find. I talked to every psychiatrist and brain
scientist who would talk to me. And I soon realized that in all my years
as a journalist I had never seen a story where the gap between insider
and outsider knowledge was so great, or the stakes so high.
I began to wonder why—with the stocks of cannabis companies soaring
and politicians promoting legalization as a low-risk way to raise tax
revenue and reduce crime—I had never heard the truth about marijuana,
mental illness, and violence.
***
Over the last 30 years, psychiatrists and epidemiologists have turned
speculation about marijuana’s dangers into science. Yet over the same
period, a shrewd and expensive lobbying campaign has pushed public
attitudes about marijuana the other way. And the effects are now
becoming apparent.
Almost everything you think you know about the health effects of
cannabis, almost everything advocates and the media have told you for a
generation, is wrong.
They’ve told you marijuana has many different medical uses. In
reality marijuana and THC, its active ingredient, have been shown to
work only in a few narrow conditions. They are most commonly prescribed
for pain relief. But they are rarely tested against other pain relief
drugs like ibuprofen—and in July, a large four-year study of patients
with chronic pain in Australia showed cannabis use was associated with
greater pain over time.
They’ve told you cannabis can stem opioid use—“Two new studies show
how marijuana can help fight the opioid epidemic,” according to
Wonkblog, a
Washington Post website, in April 2018— and that
marijuana’s effects as a painkiller make it a potential substitute for
opiates. In reality, like alcohol, marijuana is too weak as a painkiller
to work for most people who truly
need opiates, such as
terminal cancer patients. Even cannabis advocates, like Rob Kampia, the
co-founder of the Marijuana Policy Project, acknowledge that they have
always viewed medical marijuana laws primarily as a way to protect
recreational users.
As for the marijuana-reduces-opiate-use theory, it is based largely
on a single paper comparing overdose deaths by state before 2010 to the
spread of medical marijuana laws— and the paper’s finding is probably a
result of simple geographic coincidence. The opiate epidemic began in
Appalachia, while the first states to legalize medical marijuana were in
the West. Since 2010, as both the epidemic and medical marijuana laws
have spread nationally, the finding has vanished. And the United States,
the Western country with the most cannabis use, also has by far the
worst problem with opioids.
Research on individual users—a better way to trace cause and effect
than looking at aggregate state-level data—consistently shows that
marijuana use leads to other drug use. For example, a January 2018 paper
in the
American Journal of Psychiatry showed that people who
used cannabis in 2001 were almost three times as likely to use opiates
three years later, even after adjusting for other potential risks.
Most of all, advocates have told you that marijuana is not just safe
for people with psychiatric problems like depression, but that it is a
potential treatment for those patients. On its website, the cannabis
delivery service Eaze offers the “Best Marijuana Strains and Products
for Treating Anxiety.” “How Does Cannabis Help Depression?” is the topic
of an article on Leafly, the largest cannabis website. But a mountain
of peer-reviewed research in top medical journals shows that marijuana
can cause or worsen severe mental illness, especially psychosis, the
medical term for a break from reality. Teenagers who smoke marijuana
regularly are about three times as likely to develop schizophrenia, the
most devastating psychotic disorder.
After an exhaustive review, the National Academy of Medicine found in
2017 that “cannabis use is likely to increase the risk of developing
schizophrenia and other psychoses; the higher the use, the greater the
risk.” Also that “regular cannabis use is likely to increase the risk
for developing social anxiety disorder.”
***
Over the past decade, as legalization has spread, patterns of marijuana use—and the drug itself—have changed in dangerous ways.
Legalization has not led to a huge increase in people using the drug
casually. About 15 percent of Americans used cannabis at least once in
2017, up from ten percent in 2006, according to a large federal study
called the National Survey on Drug Use and Health. (By contrast, about
65 percent of Americans had a drink in the last year.) But the number of
Americans who use cannabis
heavily is soaring. In 2006, about
three million Americans reported using cannabis at least 300 times a
year, the standard for daily use. By 2017, that number had nearly
tripled, to eight million, approaching the twelve million Americans who
drank alcohol every day. Put another way, one in 15 drinkers consumed
alcohol daily; about one in five marijuana users used cannabis that
often.
Cannabis users today are also consuming a drug that is far more
potent than ever before, as measured by the amount of
THC—delta-9-tetrahydrocannabinol, the chemical in cannabis responsible
for its psychoactive effects—it contains. In the 1970s, the last time
this many Americans used cannabis, most marijuana contained less than
two percent THC. Today, marijuana routinely contains 20 to 25 percent
THC, thanks to sophisticated farming and cloning techniques—as well as
to a demand by users for cannabis that produces a stronger high more
quickly. In states where cannabis is legal, many users prefer extracts
that are nearly pure THC. Think of the difference between near-beer and a
martini, or even grain alcohol, to understand the difference.
These new patterns of use have caused problems with the drug to soar.
In 2014, people who had diagnosable cannabis use disorder, the medical
term for marijuana abuse or addiction, made up about 1.5 percent of
Americans. But they accounted for eleven percent of all the psychosis
cases in emergency rooms—90,000 cases, 250 a day, triple the number in
2006. In states like Colorado, emergency room physicians have become
experts on dealing with cannabis-induced psychosis.
Cannabis advocates often argue that the drug can’t be as neurotoxic
as studies suggest, because otherwise Western countries would have seen
population-wide increases in psychosis alongside rising use. In reality,
accurately tracking psychosis cases is impossible in the United States.
The government carefully tracks diseases like cancer with central
registries, but no such registry exists for schizophrenia or other
severe mental illnesses.
On the other hand, research from Finland and Denmark, two countries
that track mental illness more comprehensively, shows a significant
increase in psychosis since 2000, following an increase in cannabis use.
And in September of last year, a large federal survey found a rise in
serious mental illness in the United States as well, especially among
young adults, the heaviest users of cannabis.
According to this latter study, 7.5 percent of adults age 18-25 met
the criteria for serious mental illness in 2017, double the rate in
2008. What’s especially striking is that adolescents age 12-17 don’t
show these increases in cannabis use and severe mental illness.
A caveat: this federal survey doesn’t count individual cases, and it
lumps psychosis with other severe mental illness. So it isn’t as
accurate as the Finnish or Danish studies. Nor do any of these studies
prove
that rising cannabis use has caused population-wide increases in
psychosis or other mental illness. The most that can be said is that
they offer intriguing evidence of a link.
***
Advocates for people with mental illness do not like discussing the
link between schizophrenia and crime. They fear it will stigmatize
people with the disease. “Most people with mental illness are not
violent,” the National Alliance on Mental Illness (NAMI) explains on its
website. But wishing away the link can’t make it disappear. In truth,
psychosis is a shockingly high risk factor for violence. The best
analysis came in a 2009 paper in
PLOS Medicine by Dr. Seena
Fazel, an Oxford University psychiatrist and epidemiologist. Drawing on
earlier studies, the paper found that people with schizophrenia are five
times as likely to commit violent crimes as healthy people, and almost
20 times as likely to commit homicide.
NAMI’s statement that most people with mental illness are not violent
is of course accurate, given that “most” simply means “more than half”;
but it is deeply misleading. Schizophrenia is rare. But people with the
disorder commit an appreciable fraction of all murders, in the range of
six to nine percent.
“The best way to deal with the stigma is to reduce the violence,”
says Dr. Sheilagh Hodgins, a professor at the University of Montreal who
has studied mental illness and violence for more than 30 years.
The marijuana-psychosis-violence connection is even stronger than
those figures suggest. People with schizophrenia are only moderately
more likely to become violent than healthy people when they are taking
antipsychotic medicine and avoiding recreational drugs. But when they
use drugs, their risk of violence skyrockets. “You don’t just have an
increased risk of one thing—these things occur in clusters,” Dr. Fazel
told me.
Along with alcohol, the drug that psychotic patients use more than any other is cannabis: a 2010 review of earlier studies in
Schizophrenia Bulletin
found that 27 percent of people with schizophrenia had been diagnosed
with cannabis use disorder in their lives. And unfortunately—despite its
reputation for making users relaxed and calm—cannabis appears to
provoke many of them to violence.
A Swiss study of 265 psychotic patients published in
Frontiers of Forensic Psychiatry
last June found that over a three-year period, young men with psychosis
who used cannabis had a 50 percent chance of becoming violent. That
risk was four times higher than for those with psychosis who didn’t use,
even after adjusting for factors such as alcohol use. Other researchers
have produced similar findings. A 2013 paper in an Italian psychiatric
journal examined almost 1,600 psychiatric patients in southern Italy and
found that cannabis use was associated with a ten-fold increase in
violence.
The most obvious way that cannabis fuels violence in psychotic people
is through its tendency to cause paranoia—something even cannabis
advocates acknowledge the drug can cause. The risk is so obvious that
users joke about it and dispensaries advertise certain strains as less
likely to induce paranoia. And for people with psychotic disorders,
paranoia can fuel extreme violence. A 2007 paper in the
Medical Journal of Australia
on 88 defendants who had committed homicide during psychotic episodes
found that most believed they were in danger from the victim, and almost
two-thirds reported misusing cannabis—more than alcohol and
amphetamines combined.
Yet the link between marijuana and violence doesn’t appear limited to
people with preexisting psychosis. Researchers have studied alcohol and
violence for generations, proving that alcohol is a risk factor for
domestic abuse, assault, and even murder. Far less work has been done on
marijuana, in part because advocates have stigmatized anyone who raises
the issue. But studies showing that marijuana use is a significant risk
factor for violence have quietly piled up. Many of them weren’t even
designed to catch the link, but they did. Dozens of such studies exist,
covering everything from bullying by high school students to fighting
among vacationers in Spain.
In most cases, studies find that the risk is at least as significant as with alcohol. A 2012 paper in the
Journal of Interpersonal Violence
examined a federal survey of more than 9,000 adolescents and found that
marijuana use was associated with a doubling of domestic violence; a
2017 paper in
Social Psychiatry and Psychiatric Epidemiology
examined drivers of violence among 6,000 British and Chinese men and
found that drug use—the drug nearly always being cannabis—translated
into a five-fold increase in violence.
Today that risk is translating into real-world impacts. Before states
legalized recreational cannabis, advocates said that legalization would
let police focus on hardened criminals rather than marijuana smokers
and thus reduce violent crime. Some advocates go so far as to claim that
legalization
has reduced violent crime. In a 2017 speech
calling for federal legalization, U.S. Senator Cory Booker said that
“states [that have legalized marijuana] are seeing decreases in violent
crime.” He was wrong.
The first four states to legalize marijuana for recreational use were
Colorado and Washington in 2014 and Alaska and Oregon in 2015.
Combined, those four states had about 450 murders and 30,300 aggravated
assaults in 2013. Last year, they had almost 620 murders and 38,000
aggravated assaults—an increase of 37 percent for murders and 25 percent
for aggravated assaults, far greater than the national increase, even
after accounting for differences in population growth.
Knowing exactly how much of the increase is related to cannabis is
impossible without researching every crime. But police reports, news
stories, and arrest warrants suggest a close link in many cases. For
example, last September, police in Longmont, Colorado, arrested Daniel
Lopez for stabbing his brother Thomas to death as a neighbor watched.
Daniel Lopez had been diagnosed with schizophrenia and was
“self-medicating” with marijuana, according to an arrest affidavit.
In every state, not just those where marijuana is legal, cases like
Lopez’s are far more common than either cannabis or mental illness
advocates acknowledge. Cannabis is also associated with a disturbing
number of child deaths from abuse and neglect—many more than alcohol,
and more than cocaine, methamphetamines, and opioids combined—according
to reports from Texas, one of the few states to provide detailed
information on drug use by perpetrators.
These crimes rarely receive more than local attention.
Psychosis-induced violence takes particularly ugly forms and is
frequently directed at helpless family members. The elite national media
prefers to ignore the crimes as tabloid fodder. Even police
departments, which see this violence up close, have been slow to
recognize the trend, in part because the epidemic of opioid overdose
deaths has overwhelmed them.
So the black tide of psychosis and the red tide of violence are rising steadily, almost unnoticed, on a slow green wave.
***
For centuries, people worldwide have understood that cannabis causes
mental illness and violence—just as they’ve known that opiates cause
addiction and overdose. Hard data on the relationship between marijuana
and madness dates back 150 years, to British asylum registers in India.
Yet 20 years ago, the United States moved to encourage wider use of
cannabis and opiates.
In both cases, we decided we could outsmart these drugs—that we could
have their benefits without their costs. And in both cases we were
wrong. Opiates are riskier, and the overdose deaths they cause a more
imminent crisis, so we have focused on those. But soon enough the mental
illness and violence that follow cannabis use will also be too
widespread to ignore.
Whether to use cannabis, or any drug, is a personal decision. Whether
cannabis should be legal is a political issue. But its precise legal
status is far less important than making sure that anyone who uses it is
aware of its risks. Most cigarette smokers don’t die of lung cancer.
But we have made it widely known that cigarettes cause cancer, full
stop. Most people who drink and drive don’t have fatal accidents. But we
have highlighted the cases of those who do.
We need equally unambiguous and well-funded advertising campaigns on
the risks of cannabis. Instead, we are now in the worst of all worlds.
Marijuana is legal in some states, illegal in others, dangerously
potent, and sold without warnings everywhere.
But before we can do anything, we—especially cannabis advocates and
those in the elite media who have for too long credulously accepted
their claims—need to come to terms with the truth about the science on
marijuana. That adjustment may be painful. But the alternative is far
worse, as the patients at Mid-Hudson Forensic Psychiatric Institute—and
their victims—know.
Trent England
is executive vice president and the David and Ann Brown Distinguished
Fellow at the Oklahoma Council of Public Affairs, where he also directs
the Save Our States project. He earned his B.A. in government from
Claremont McKenna College and his J.D. from the George Mason University
School of Law. He previously served as executive vice president of the
Freedom Foundation and as a legal policy analyst at the Heritage
Foundation. He hosts the podcast, The Trent England Show, and has written for numerous publications, including The Wall Street Journal, Christian Science Monitor, and The Washington Times. He is a contributor to The Heritage Guide to the Constitution.
