Karen Randall, an emergency physician in Colorado, says “scromiting” cases were rare several years ago. Now she’s seeing at least one per day.

Scromiting is shorthand for scream-vomiting, a condition that inflicts patients who use marijuana with high concentrations of tetrahydrocannabinol or THC, the psychoactive substance in cannabis.

The condition is pretty much what it sounds like — a person screaming from nausea and vomiting at the same time.

“It’s a super huge issue,” said Dr. Randall, a practicing emergency medicine physician and vice president of case management at Southern Colorado Emergency Medicine Associates in Pueblo, Colorado — one of the first states to legalize recreational marijuana use over a decade ago. “They don’t necessarily have to be daily users. But they’re frequent users, and they’re using the high-concentrate.”

Weed is getting more potent as states rush to legalize it, raising fears that marijuana with little resemblance to Woodstock-era grass is causing psychosis, suicidal thoughts and a parade of other health problems despite the mainstream dogma that pot is harmless.

Mounting data and an eyebrow-raising report about schizophrenia rates in Denmark are ringing alarm bells in Washington and casting a harsh light on the relative lack of limits on how much THC can be put in a range of cannabis products that are smoked, vaped or ingested.

“The higher the potency, the more addictive it is. It’s the addiction-for-profit model,” said Luke Niforatos, executive vice president of Smart Approaches to Marijuana, an organization that warns about the potential harm of marijuana use. “Once there was an industry producing and selling and manufacturing marijuana products, that’s when we saw potency start to skyrocket.”

Colorado and Washington state in 2012 became the first states to legalize recreational marijuana. Since then, 19 states and the District of Columbia have joined them, though states have varying approaches to sales.

Now more people are using marijuana and doing so more frequently.

Data compiled by SAM show 52.5 million Americans used marijuana in 2021 versus 17.5 million in 1992, and the number of persons age 12 or older reporting daily use increased from 6.2 million in 2009 to 13.8 million in 2019.

At the same time, the average potency of marijuana plant material has jumped from between 1% and 3% in the 1970s to from 18% to 23% today.

The amount of THC concentrates known as “shatter,” “budder” and “waxes” jumped during the legalization era from an average THC potency of 6.7% in 2008 to 55% by 2017. Some retailers advertise products containing as much as 99% THC, according to published medical articles.

Health officials in Washington State said they’ve seen a proliferation of new high-concentrated THC products on the marketplace since legalization in 2012. Concentrates made 35% of the cannabis market in Washington state by 2019, an increase from 9% in 2014.

As a result, modern users who vape or take other concentrates are generally taking in far more THC than people who used to pass around a joint at parties.

“If you look at use now, you have your own vape pen, you don’t share and you’re using massive quantities,” Dr. Randall said.

The rush to legalize weed is challenging the “Iron Law of Prohibition,” which argues that drugs get more potent if they are outlawed. There is an economic logic to this notion because “the greater the sanction risk, the more valuable it is to make things compact, which ought to favor potency,” said Jonathan Caulkins, a professor of operations research and public policy at Carnegie Mellon University.

“But folks who hate prohibition converted that to an ‘iron law’ just by wishing it to be so, and the facts clearly contradict it for cannabis,” he said. “It’s very clear that legalization has led to potencies that are much, much higher.”

Many politicians and industry players have pushed to loosen pot restrictions by saying the overhaul will advance social justice and equity without causing much societal harm. Yet a growing body of evidence is revealing a toll on public health.

A major 2019 study published in The Lancet Psychiatry showed that places in Europe — London, Paris and Amsterdam — had higher rates of psychosis cases than other places in the study. Highly potent weed, defined as at least 10% THC concentration, was more commonly available in those cities.

That same year, U.S. Surgeon General Jerome Adams issued a major advisory warning that “the marijuana available today is much stronger than previous versions” and could be devastating for young users whose brains are still forming. It warned that high doses of THC are more likely to produce anxiety, agitation, paranoia and psychosis.

“The psychosis, that’s so profoundly real,” said Dr. Randall, who is certified in cannabis science and medicine.

She said sufferers are a range of ages, though the youngest she’s seen was 7 years old.

“They’re very violent, very paranoid,” she said.

In February, the American Health Association said it surveyed over 2,500 people ages 13-24 and found 70% of the THC-only vapers and 60% of the nicotine-only vapers and dual vapers reported anxiety symptoms — worries, flashbacks, panic attacks and situational anxieties — within the prior week, compared to about 40% of participants who had never vaped.

More than 50% of people in all vaping groups reported having suicidal thoughts within the past 12 months, compared to one-third of non-users.

And last week, the National Institutes of Health released a major study by its scientists and Danish partners that found young men who abuse marijuana have a higher risk of developing schizophrenia, a disorder in which people have difficulty participating in everyday activities.

The study examined health records data spanning five decades and representing more than 6 million people in Denmark to explore the link between cannabis use disorder and schizophrenia. Scientists determined 30% of cases of schizophrenia among men ages 21-30 might have been prevented by averting marijuana use.

The NIH said it is concerned about the emerging trend around high-THC products.

“As access to potent cannabis products continues to expand, it is crucial that we also expand prevention, screening, and treatment for people who may experience mental illnesses associated with cannabis use,” said Dr. Nora Volkow, director of the National Institute on Drug Abuse.

Laura Stack, of Colorado, said the Danish study didn’t surprise her at all.

Her son, Johnny, died of suicide by jumping from a six-floor building at age 19 after his marijuana use, which included vapes and highly concentrated “dabs,” made him “very paranoid and suspicious.”

“It’s not uncommon. It’s just something that hasn’t gotten a lot of play,” she said in a phone interview.

Ms. Stack launched a nonprofit, Johnny’s Ambassadors: Youth Marijuana Prevention, to speak at schools and warn other parents about the perils of marijuana use in young people.

She said there are over 600 parents in the organization’s Parents of Children with Cannabis Induced Psychosis support group, underscoring the prevalence of the issue.

Conversations about the potential dangers of rampant marijuana use are often eclipsed on the national stage by worries about scourges like fentanyl, which is the number-one driver of the overdose crisis killing more than 100,000 Americans per year.

Ms. Stack said the parents she meets do not compare marijuana to fentanyl, though many do view pot as benign.

“I ask them, ‘When’s the last time you used weed?” she said. “It’s not even the same drug [anymore].”

A form of ingestion known as dabbing is sparking the greatest alarm. The process involves concentrating THC into a solvent so that it resembles a sticky oil that is then heated and inhaled.

“The kids use spoons, straws, nails. They steal their parents’ butane torch for the crème brûlée from the kitchen,” Ms. Stack said. “You are high out of your mind. The kids get the serving size wrong all the time.”

Advocates for marijuana legalization point to studies that failed to find a causal link between cannabis use and things like psychosis. They also say acute cannabis-induced psychosis is rare, or that persons who experience it are either predisposed to psychosis or have a pre-existing psychiatric disorder.

The NORML Foundation, a group that advocates for the responsible use of marijuana by adults, said it does not support criminalizing products with high concentrations because it would drive the production and sale of them underground. It says regulators and concerned parties should provide the public with more comprehensive safety information about the effects of potent marijuana products while ensuring products don’t get diverted to the youth market.

“Typically, when consumers encounter higher potency products, they ingest smaller quantities of them. There’s even a medical term for it: ‘self-titration,’” Paul Armentano, deputy director of NORML, wrote in a commentary for OtherWords, an editorial service published by the Institute for Policy Studies. “Second, higher potency THC products do not dominate state-legal markets. Retail sales records from these markets show that most consumers tend to prefer and to gravitate toward flower products of more moderate potency. Third, unlike alcohol, THC is incapable of causing lethal overdose, regardless of either its potency or the quantity consumed.”

Yet some experts warn that financial incentives will drive people into higher-strength products in greater numbers.

“Addicted customers are the most profitable customers. What stops this? Proper regulation. You can’t sell 50% ethanol content beer because the law says so. We have no such laws around cannabis. At the moment, it’s the job of states that have legalized to put those regulations in place,” said Keith Humphreys, a Stanford University professor who tracks drug issues. “So far most of those supporting legalization at the federal level have shown little interest in regulating the industry at all. They want cannabis de-scheduled and don’t care much about regulating against risks.”

Only two states, Connecticut and Vermont, have capped THC content — at 30% for cannabis flower and 60% for THC concentrates — while other states require warning labels for high-concentrate products.

“It’s still extremely high. But those two states have at least done something about it,” Mr. Niforatos said. “Most researchers agree it really needs to be more down to in the 15% range, 10% range — which, you know, that’s a complete nonstarter for the marijuana industry.”

He thinks there should be a nationwide education campaign about high-potency marijuana because “nobody knows what’s out there.” He would also like to see the Department of Justice clamp down on “extreme actors” in the high-THC markets, given that marijuana is still illegal at the federal level. 

Pressed on marijuana policy, Attorney General Merrick Garland told the Senate Judiciary Committee in March he is still working on a marijuana policy for the department. He said the policy will likely track with the Cole Memo, an Obama-era letter that told states it would not use federal resources to crack down on states that legalized marijuana use and put regulatory guardrails in place.

Mr. Garland said the Department of Health and Human Services, meanwhile, “is working on the question of scientific analysis of marijuana.”

The NIH says the federal ban on marijuana as a Schedule I drug makes it hard for their taxpayer-funded scientists to test and study highly potent pot products that are legally available to users in nearly a dozen states. Congress passed a law last year to set up a registration process for marijuana research but the NIH said significant legal and regulatory barriers remain.

“This makes it difficult for researchers to verify whether the claims being made by the companies selling these products are true, and prevents scientists from fully understanding the health effects, potential risks, and potential benefits of products containing cannabis,” the National Institute on Drug Abuse told The Washington Times.

Some states are pushing back on legalization. While Missouri voters approved a state constitutional amendment in November to allow recreational use, a string of voters in other states — Arkansas, Oklahoma North Dakota and South Dakota — have rejected similar measures.

Washington state lawmakers debated a pair of bills that would raise taxes or age limits on marijuana concentrates, or more tightly regulate the concentrate market, but both died in committee.

Ms. Stack pointed to a policy change in Colorado, which tightened the rules around medical patients ages 18 to 20, including purchase limits and a requirement that young medical marijuana patients get recommendations from two doctors. In the past, she said, high school students would rush out for a medical card once they became seniors. They would also distribute products to younger students.

She said parents should do their diligence by forbidding their kids from using marijuana and keeping close tabs on their smartphone usage, particularly at night, so they don’t order pot through social media apps.

“So many believe it is harmless, so I would tell them: Get educated,” she said. “With my son, there wasn’t a Johnny’s Ambassadors when this was happening. I had nowhere to go. No one believed me.”

• Tom Howell Jr. can be reached at thowell@washingtontimes.com.