As America’s Marijuana Use Grows, So Do the Harms

The drug, legal in much of the country, is widely seen as nonaddictive and safe. For some users, these assumptions are dangerously wrong.

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By Megan TwoheyDanielle Ivory and Carson Kessler

The reporters are continuing to examine cannabis policies, use of the drug and the rise of the commercial market. If you have a story or information to share, please contact us here.

Published Oct. 4, 2024Updated Oct. 5, 2024

In midcoast Maine, a pediatrician sees teenagers so dependent on cannabis that they consume it practically all day, every day — “a remarkably scary amount,” she said.

From Washington State to West Virginia, psychiatrists treat rising numbers of people whose use of the drug has brought on delusions, paranoia and other symptoms of psychosis.

And in the emergency departments of small community hospitals and large academic medical centers alike, physicians encounter patients with severe vomiting induced by the drug — a potentially devastating condition that once was rare but now, they say, is common. “Those patients look so sick,” said a doctor in Ohio, who described them “writhing around in pain.”

As marijuana legalization has accelerated across the country, doctors are contending with the effects of an explosion in the use of the drug and its intensity. A $33 billion industry has taken root, turning out an ever-expanding range of cannabis products so intoxicating they bear little resemblance to the marijuana available a generation ago. Tens of millions of Americans use the drug, for medical or recreational purposes — most of them without problems.

But with more people consuming more potent cannabis more often, a growing number, mostly chronic users, are enduring serious health consequences.

The accumulating harm is broader and more severe than previously reported. And gaps in state regulations, limited public health messaging and federal restraints on research have left many consumers, government officials and even medical practitioners in the dark about such outcomes.

Again and again, The New York Times found dangerous misconceptions.

Many users believe, for instance, that people cannot become addicted to cannabis. But millions do.

About 18 million people — nearly a third of all users ages 18 and up — have reported symptoms of cannabis use disorder, according to estimates from a unique data analysis conducted for The Times by a Columbia University epidemiologist. That would mean they continue to use the drug despite significant negative effects on their lives. Of those, about three million people are considered addicted.

The estimates are based on responses to the 2022 U.S. national drug use survey from people who reported any cannabis consumption within the previous year. The results are especially stark among 18- to 25-year-olds: More than 4.5 million use the drug daily or near daily, according to the estimates, and 81 percent of those users meet the criteria for the disorder.

“That means almost everybody that uses it every day is reporting problems with it,” said Dr. Wilson Compton, deputy director of the National Institute on Drug Abuse, who was not involved in the analysis. “That is a very clear warning sign.”

Marijuana is known for soothing nausea. But for some users, it has the opposite effect.

Credit…Kevin Serna for The New York Times

“Why don’t more doctors know about it? Why didn’t anyone ever mention it to me?”

Jennifer Macaluso suffered terrible health effects using cannabis for migraine headaches.

Jennifer Macaluso, a hairdresser in Elgin, Ill., turned to the drug in her 40s when a doctor suggested it to help her severe migraines. Starting in 2019, whenever she felt a headache coming on she would take a hit of a marijuana vape pen and pop an edible from a medical cannabis dispensary. It worked.

But after several months, she developed stomachaches. A dispensary employee advised upping her intake, and eventually she was using the drug nearly every day. Within months came episodes of nausea and vomiting so debilitating that she had to stop working.

About a dozen doctors misdiagnosed the problem. One removed her gallbladder, another her breast implants. Several chalked up her symptoms to menopause.

After searching online in 2022, Ms. Macaluso suspected she had cannabinoid hyperemesis syndrome, a condition caused by heavy cannabis use and marked by nausea, vomiting and pain. It can lead to extreme dehydration, seizures, kidney failure and cardiac arrest. In rare cases, it has caused deaths — at least eight in the United States, including some newly identified by The Times.

Since the syndrome was first documented in 2004, doctors say they have observed a sharp rise in cases. Because it is not recorded consistently in medical records, the condition is nearly impossible to track precisely. But researchers have estimated that as many as one-third of near-daily cannabis users in the United States could have symptoms of the syndrome, ranging from mild to severe. That works out to roughly six million people.

Eventually a new physician confirmed Ms. Macaluso’s diagnosis, noting that new cases were coming in every week. “I was angry that doctors hadn’t caught it and that I suffered so much,” Ms. Macaluso said. She had continued to use the drug, she added, “because I thought it was helping.”