Study finds U.S. adult usage of ‘magic mushrooms’ has doubled since decriminalization began 5 years ago in Denver

Use of psilocybin — the psychedelic compound found in “magic mushrooms” — has doubled among U.S. adults since Denver began decriminalizing the drug in 2019, according to researchers with Rocky Mountain Poison and Drug Safety.

Joshua Black, one of the authors of the peer-reviewed study published last month in the Annals of Internal Medicine, explained that researchers used 2019 as a reference point because that was the first time a government in the U.S. had decriminalized psilocybin.

“Our goal was to see ‘How have use patterns changed across multiple different age groups since that time?'” Black said. “We wanted to use a comprehensive approach. So, in our study we looked at multiple different data sources that assessed different ages as well as medical outcomes for individuals who are using psilocybin.”

Researchers analyzed five nationally representative data sets, including the National Survey on Drug Use and Health and the National Poison Data System, to estimate psilocybin use, Black said.

The percentage of U.S. adults who have used psilocybin over the past year increased from around 1% prior to 2019 to about 2.1% by 2023, Black said. That means more adults are now using psilocybin than cocaine, LSD, methamphetamine or illicit opioids, making it the second most-used drug behind cannabis, he said.

“The primary conclusion here is that psilocybin isn’t a niche drug anymore,” Black said. “Its use has doubled since 2019, and it’s eclipsed the (usage of) other drugs that tend to be discussed that may have potentially adverse outcomes for individuals who use.”

The increase in psilocybin use is an important observation that could have implications for policymakers as governments decriminalize and legalize certain medical uses of the drug, Black said. While there have been clinical trials demonstrating the potential benefit of psilocybin use for mental health conditions, “those trials need to be repeated and the efficacy demonstrated,” he said.

Since 2019, other governments in the U.S. have taken steps to decriminalize psilocybin. In 2022, Colorado voters approved Proposition 122, making it the second state, behind Oregon, to decriminalize psilocybin. This year, Colorado began issuing licenses for its first “healing centers,” where psilocybin can be administered alongside therapy.

“(Decriminalization) has already happened. It’s already been happening for five years,” Black said. “Any state or other body that is choosing to decriminalize, they should be thoughtful about ensuring they know how to collect the best information to make sure those policies are keeping people as safe as possible.”

The study found the estimated percentage of U.S. adults who have used psilocybin at least once in their lives rose from 10% in 2019 to 12.1% by 2023 — an increase from about 25 million adults having used the drug to more than 31 million. Since 2019, past-year psilocybin use increased 44% among young adults ages 18 to 29 and 188% among older adults, according to the study. 

Moreover, the increases in psilocybin use weren’t limited to adults. The estimated percentage of U.S. adolescents ages 12 to 17 who used psilocybin in their lifetimes increased from 1.1% in 2019 to 1.3% in 2023, the study found. That’s an increase from about 285,000 adolescents in 2019 to about 344,000 in 2023.

With millions more people using psilocybin than just a handful of years ago, Black said “it’s important to understand the health outcomes that are associated with psilocybin use — and that’s both the positive health outcomes and the negative ones.” 

“On one hand there could be quite a positive benefit for individuals,” Black said. “On the other hand though, there are certainly potential adverse outcomes associated with psilocybin use. There is obviously the intended hallucinogenic effect, but not everyone reacts to that effect the same way.”

When researchers analyzed data related to healthcare outcomes they found “two data sources sort of conflicted,” Black said. While researchers found a significant increase in the number of cases of psilocybin exposures reported to poison control reports, they found comparably few records at emergency departments and outpatient facilities.

The study found that between 2019 and 2023, the rate of psilocybin exposures reported to poison centers across the U.S. increased 201% in adults, 317% in adolescents and 723% in children ages zero to 11.

Nationwide, in 2023, there were 1,192 cases of psilocybin exposure reported to poison control involving adults, 542 cases involving adolescents and 288 involving children, of which about 75% reported involvement of a healthcare facility, according to the study.

Looking at another data set, the study found only three cases of psilocybin poisoning recorded at emergency departments and outpatient facilities between 2015 and 2021, a discrepancy Black said could have implications for future data collection.

“From a researcher’s standpoint, that’s important for us to observe so that as the legal landscape of psilocybin use across the country changes, we have the right data sets in place to monitor those changes and ensure people are using safely,” Black said.

For those who might use psilocybin, Black said the study has another implication — not everyone reacts to the drug’s hallucinogenic effects the same. 

“Plan before you trip,” he said, suggesting that anyone using psilocybin do so in a comfortable, safe place and with a trusted friend who is not tripping in case of a poor reaction to the drug’s effects.

Ultimately, the study found that decriminalization appears to have led to a marked increase in psilocybin use across all age groups, something policy makers should be aware of, Black said. Similar to cannabis decriminalization, he said he expects psilocybin use in the U.S. will continue to increase if the drug continues to be decriminalized.

“Decriminalization does affect the prevalence of use when a drug is more available. It becomes less stigmatized (with) fewer criminal penalties,” Black said. “So I think as long as the decriminalization process continues, we’ll definitely see an increase in use overtime. If that process stops, then we may see a plateauing. But the data will tell. Time will tell.”