Liz Kirkaldie’s grandson was top of his class in high school and a talented jazz bassist when he started smoking weed. The more seriously he was interested in music, the more he was interested in weed.

And the more seriously he took weed, the more paranoid, even psychotic, he became. He started to hear voices.

“They were going to kill him and there were people coming and eating his brain. Weird, weird stuff,” Kirkaldie says. “I woke up one morning, and no Kory anywhere. Well, turns out he was running around Villa Lane here, totally naked.”

Kory came to live with his grandmother for a few years in Napa, California. She thought maybe she could help. Now she says that was naive.

Kory was diagnosed with schizophrenia. Kirkaldie blames the pot.

“The drug use activated the psychosis, that’s what I really think,” she says.

In effect, numerous scientific studies have linked marijuana use to an increased risk of developing psychiatric disorders, including schizophrenia. The risk is greater than four times bigger for people who use high potency marijuana daily, compared to those who have never used it, according to to a study Posted in The Lancet Psychiatry in 2019. A study found that eliminating marijuana use among adolescents would reduce global rates of schizophrenia by 10%.

California doctors and lawmakers want cannabis producers to warn consumers about this and other health risks on their packaging labels and in advertising, similar to requirements for cigarettes. They also want vendors to hand out health brochures to new customers outlining the risks cannabis poses to young people, drivers and pregnant women, especially for pot that contains high levels of THC, the chemical primarily responsible. mental effects of marijuana.

“Today’s supercharged products amplify the harms associated with cannabis,” says Dr. Lynn Silver of the Public Health Institutea non-profit organization sponsoring the labeling bill, SB 1097the Cannabis Right to Know Act.

Californians voted to legalize recreational pot in 2016. Three years later, emergency room visits for cannabis-induced psychosis rose 54% statewide, from 682 to 1,053, according to data from the state hospital. For people who already have a psychotic disorder, cannabis makes things worse, leading to more emergency room visits, more hospitalizations and more legal problems, says Dr Deepak Cyril D’Souzaprofessor of psychiatry at Yale University School of Medicine who also sits on the physician advisory board for the Connecticut Medical Marijuana Program.

But D’Souza has great difficulty convincing his patients of the dangers, especially since 19 states and the District of Columbia legalized recreational marijuana.

“My patients with schizophrenia, as well as teenagers, are hearing very mixed messages that it’s legal; in fact, there may be medical uses,” he says. “If there are medical uses, how can we tell there is something wrong?”

Legalization is not the problem, he says, but rather the commercialization of cannabis – the intensive marketing, which may aim to entice young people to become lifelong customers, and the increase in THC from 4% on average to between 20% and 35% in today’s varieties.

Limiting the amount of THC in potted products and including health warnings on labels could help reduce the health harms associated with cannabis use, D’Souza says, the same way these methods have worked for people. cigarettes. He credits warning labels, education campaigns and marketing restrictions for the sharp decline in smoking rates among children and adolescents in the last decade.

“We know how to message them,” D’Souza says. “But I don’t think we have the will or the resources yet.”

Some states, including Colorado, Oregon and New York, have looked into requirements for cannabis warning labels. California’s proposed rules are modeled after comprehensive protocols established in Canada: Rotating health warnings would be placed on a bright yellow background, use 12-point black font, and take up one-third of the front of the package. The bill proposes language for 10 separate warnings, including:

Matthew Green/KQED

Opponents of the proposed warning labels say the requirements are excessive and onerous, especially since marketing to children is already banned in California and people must be 21 to buy.

“This bill is truly duplicative and places unnecessary burdens on the legal cannabis industry, because we already have incredibly restrictive packaging and advertising requirements,” said Lindsay Robinson, executive director of the California Cannabis Industry Associationwhich represents legal pot businesses.

The state should focus more on tackling the illicit cannabis market rather than regulating the legal market, she says. Legal dispensaries are already struggling to keep up with existing rules and taxes — the state’s 1,500 licensed pot retailers have generated $1.3 billion in state tax revenue Last year. Adding more requirements just makes it harder for them to compete with the illicit market, she says, and more likely to go bankrupt.

“The only real option if they fail to get out of the legal system is to shut down their businesses completely or operate underground. And I don’t think the State of California, with the tax revenue, wants one or the other happen,” she said. . “The crux of the matter is that there is a massive, unregulated market in the state.”

Liz Kirkaldie holds a photo of her grandson, Kory, as a child. He started smoking weed in high school and developed schizophrenia. Beth LaBerge/KQED

Some people doubt that labels work. Liz Kirkaldie’s grandson, Kory, is now stable and lives with his father. But she’s not sure a yellow warning would have stopped him when he was a teenager.

“They just won’t pay attention,” she said. “But if it helps even one person? Great.”

Scientists still don’t know what causes schizophrenia, but they believe several factors are at play, including genetics, family history, trauma and other influences in a person’s environment, such as smoking pot. marijuana. Some scientists believe that schizophrenia itself is what predisposes people to smoking pot. While it’s difficult to prove a direct causal link between cannabis use and schizophrenia, the associations are strong enough to warrant action, D’Souza says, and importantly, pot use is one of the only risk factors that people can control.

“Not everyone who smoked cigarettes developed lung cancer, and not everyone who had lung cancer smoked cigarettes,” he says. “But I think we would all agree that one of the most preventable causes of lung cancer is smoking.”

Applying the same health education strategies to cannabis that have been used for tobacco, he says, is long overdue.

This story comes from NPR’s reporting partnership with KQED and Kaiser Health News (KHN).