The use of psilocybin — the hallucinogenic compound found in “magic mushrooms” — has increased significantly in Denver and throughout the country, driving a spike in calls to national poison control centers, a study found.

Researchers from Denver Health’s Rocky Mountain Poison & Drug Safety Center and the University of Colorado Anschutz Medical Campus found that the use of psilocybin increased nationwide across all age groups, especially among adolescents and those over 30.

“We found that since 2019, the number of people using psilocybin has gone up sharply,” said Karilynn Rockhill, co-lead author of the study and a researcher at the Colorado School of Public Health, in a news release. “This seems to line up with when some U.S. states began to decriminalize or legalize it.”

In 2022, Colorado passed Proposition 122, which decriminalized the personal use of five psychedelic substances, including psilocybin, though the sale of psilocybin remains illegal. Colorado was the second state in the nation to decriminalize its use after Oregon. The study, published on April 21 in the Annals of Internal Medicine, noted that adults who reported using psilocybin increased from 25 million people in 2019 to 31 million people in 2023.

Use among young adults (ages 18–29) increased by 44% from 1.2 million users in 2019 to 1.7 million in 2023.

The rate for those 30 years and older increased by 188%, from 1.3 million in 2019 to 3.8 million in 2023.

Use among 12th graders increased by 2.4% in 2023, but rose 53% over five years.

While the study only had official data through 2023, additional information being collected for 2024 is showing a continued rise, Dr. Andrew Monte, a professor of emergency medicine at the University of Colorado Anschutz Medical Campus in Aurora, told CNN.

The study also noted that, while only three instances of psilocybin exposure were documented nationwide by hospital emergency rooms and outpatient clinics from 2019 to 2023, there were marked increases in the number of calls to poison control centers.

There were 396 calls to poison control centers for psilocybin exposure in 2019 by adults. That number rose to 1,192 calls in 2023, an increase of 201%.

The number of calls grew by 317%, from 130 in 2019 to 542 calls in 2023, for adolescents 12 to 17 years old.

Poison control calls for children under 12 saw the biggest increase with 35 calls in 2019 rising to 288 calls in 2023, a 723% increase.

The “mismatch” between what hospitals report and the number of calls to poison control centers, according to Joshua Black, senior scientist at the Rocky Mountain Poison & Drug Safety Center, tells researchers that they’ve “lacked visibility into the real-world health impacts of psilocybin use.”

Locally, between March and December 2024, Colorado’s poison center was contacted 133 times for psychedelic exposure, a Denver Health statement said in January, adding that the ages for those calls ranged from 10 months to 90 years old.

Those kind of numbers worry Rachel O’Bryan, co-founder of One Chance to Grow Up, a nonprofit focused on youth use and unintended consequences resulting from state policy surrounding marijuana and other controlled substances.

“This study is very timely because we’ve only just begun the licensing of healing centers. So, now we have a baseline number that we will be able to track going forward,” O’Bryan told The Denver Gazette.

Lawmakers want more data on use

At the state Capitol, lawmakers said they want more data on psilocybin’s use.

Senate Bill 25-297 is making its way through the legislative process. Under the bill, the Colorado Department of Public Health and Environment, Department of Revenue and Department of Regulatory Agencies would be required to collect information and data on the use of psilocybin therapy in the state, including negative health impacts, impacts on health care facilities, law enforcement incidents, and consumer protection claims against facilitators. Data collection efforts would be funded by gifts, grants and donations from nonprofits and academic institutions, and all data would be stripped of any identifying information for security and privacy purposes.

Adults over 21 years of age in Colorado may possess, cultivate and give away psilocybin-containing mushrooms, but are prohibited by law from selling them. They may also access psychedelic-assisted centers, where patrons can experience the effects of the mushrooms in a supervised environment.

The licensing and regulation of “natural medicines” in Colorado falls under two state agencies: the Department of Revenue (DOR) and the Department of Regulatory Agencies (DORA). The Natural Medicine Division in the DOR licenses and regulates those businesses — clinics, cultivators, manufacturers, testing facilities, and their owners and employees. DORA licenses and regulates the facilitators of such services.

In March, DORA issued its first operational license for what’s called “psychedelic-assisted therapy” to The Center Origin at 1440 Blake St. in Denver.

Some early research suggests potential with the use of psilocybin for the treatment of certain conditions, such as depression and anxiety, and the study found that people with mental health conditions or chronic pain were more likely to report using psilocybin. However, psilocybin has not been approved by the U.S. Food and Drug Administration for treatment.

Critics insist that the substance is linked with suicide and accidental deaths, as well as associated with psychosis. Critics have also been pushing for strict oversight, arguing it is necessary because psychedelics are being promoted and “normalized on social media in the same way that marijuana has been for the past decade.”

‘A problem and an opportunity’

Researchers agree that as interest continues to grow in the use of psilocybin, more attention needs to be directed to data and policy development.

“It’s important to collect (data) now because things are changing,” Black said. “I think it’s possible to go backward in time to understand what’s happening, and with the changes in policy and the increased availability, I think the general public needs to understand the best ways, the safest ways to use substances, as well as the potential health opportunities.”

Black added that having “the best, most accurate information” about psilocybin use helps individuals make healthy choices.

As public views continue to change, Black said psilocybin has grown to be the second most commonly used controlled substance, behind only cannabis, and so its prevalence is quite high relative to other drugs.

“I think it’s both a problem and an opportunity,” Black said. “I think there’s a lot of very interesting evidence in clinical trials showing that these drugs may have quite meaningful benefits for people who are suffering from mental health conditions or substance use. And so, going into the future, (we need to ensure) that we balance the benefits that come from a novel pharmacotherapy against the potential risks individuals may face if they’re using in unsafe ways.”