[Dr. Libby Stuyt], a recently retired addiction psychiatrist in Pueblo, Colorado, treated patients with severe drug dependency. Typically, that meant alcohol, heroin, and methamphetamines. But about five years ago, she began to see something new.

“I started seeing people with the worst psychosis symptoms that I have ever seen,” she told me. “And the worst delusions I have ever seen.”

These cases were even more acute than what she’d seen from psychotic patients on meth. Some of the delusions were accompanied by “severe violence.” But these patients were coming up positive only for cannabis.

Stuyt wasn’t alone: Health care professionals throughout Colorado and all over the country were seeing similar episodes.

Ben Cort, who runs an addiction recovery center in Steamboat Springs, Colorado, watched a young man jump up on the table in the emergency department and strip naked, claiming he was the God of thunder and threatening to kill everyone in the room, including two police officers. A collegiate athlete Cort worked with also had a psychotic episode and was shot five times by the police with a beanbag gun before he was subdued. In Los Angeles County, Blue Stohr, a psychiatric social worker, had a patient who climbed a 700-foot crane and considered jumping off of it, not because he was suicidal but because he thought he was in a computer simulation, like The Matrix.

Those patients, too, were high only on cannabis.

In 2012, Colorado legalized marijuana. In the decade since, 18 other states have followed suit. As billions of dollars have flowed into the new above-ground industry of smokable, edible, and drinkable cannabis-based products, the drug has been transformed into something unrecognizable to anyone who grew up around marijuana pre-legalization. Addiction medicine doctors and relatives of addicts say it has become a hardcore drug, like cocaine or methamphetamines. Chronic use leads to the same outcomes commonly associated with those harder substances: overdose, psychosis, suicidality. And yet it’s been marketed as a kind of elixir and sold like candy for grown-ups.

* * * * * * * *

Prior to legalization, marijuana plants were bred to produce higher and higher concentrations of THC, a naturally occuring chemical compound in the plant that induces euphoria and alters users’ perceptions of reality. In the 1960s, the stuff the hippies were smoking was less than 2% THC. By the ’90s, it was closer to 5%. By 2015, it was over 20%. “It’s a freak plant that resembles nothing of what has existed in nature,” said Laura Stack, a public speaker who has advocated against the industry since her son, Johnny, killed himself three years ago at 19 years old after years of cannabis abuse drove him into psychosis.

Flashback: Second Thoughts on Pot: “‘Yeah, they all smoke.’ ‘Well . . . other things too, right?’ ‘Sometimes. But they all smoke.’”