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 is 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 or 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 asked.
"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 had covered the pharmaceutical industry for The New York Times. I was aware of the claims about marijuana as medicine, and I had watched the slow spread of legalized cannabis without much interest.
Jackie would have been within her rights to say, "I know what I am talking about, unlike you." Instead, she offered something neutral like, "I think that is 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 spoke with every psychiatrist and brain scientist who would talk to me--and I soon realized that, in all my years as a journalist, I never had 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 never had 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 now are 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 have 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 most commonly are prescribed for pain relief, but they rarely are tested against other pain relief drugs like ibuprofen--and, in July 2018, a large four-year study of patients with chronic pain in Australia showed cannabis use was associated with greater pain over time.
They have 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--because 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, cofounder of the Marijuana Policy Project, acknowledge that they always have 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 probably is 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...