About 8 million Americans, roughly 2.8% of the population, used psilocybin in 2024, according to a study led by UC San Diego researchers. The analysis of the federal National Survey on Drug Use and Health was published in the American Journal of Psychiatry in April 2026, and it found young adults were the most likely to have used it.1
What did the study find?
The team, from UC San Diego and NYU, looked at the 2024 national survey and estimated past-year psilocybin use at about 2.8% of Americans. Adults aged 18 to 25 were 1.4 times as likely to have used psilocybin as people in their late 30s and 40s. The first author is Dr. Kevin Yang, a psychiatry resident at UC San Diego.1
In 2024, KPBS described Yang as one of the UC San Diego researchers behind a study showing online searches for microdosing rose about 1,250% between 2015 and 2023.2
Are more people ending up at poison centers?
Yes, though from a small base. U.S. poison-center encounters involving psilocybin rose from 477 in 2013 to 1,441 in 2022, with almost all of the increase since 2019. They were most common among people aged 18 to 44, and they remained far lower than encounters involving other mushrooms and toxic plants.3 A separate study counted 4,055 psilocybin exposures among 13- to 25-year-olds reported to U.S. poison centers from 2013 to 2022, with adolescent cases more than tripling between 2018 and 2022.4
What can't the numbers tell us?
Survey data relies on people reporting their own use, and it doesn't show what they actually took. That matters in San Diego, where "mushroom" gummies and chocolate bars sold in smoke shops are common. When researchers tested 12 "magic mushroom" edibles bought in Portland, none contained psilocybin, and 8 contained undisclosed active ingredients such as synthetic tryptamines, kava or THC.5 Some of the people counted as psilocybin users may have taken something else entirely.
The published summary also reports national figures only, so there's no San Diego estimate, and it doesn't separate microdosing from larger amounts or say why people used it. Those are the questions that matter most for anyone trying to judge local risk, and they'll need different studies to answer.
Our guide to smoke-shop mushroom gummies in San Diego covers what's been found in them.
The study also doesn't change the law. Psilocybin is still a controlled substance in California, and San Diego hasn't adopted any local decriminalization measure; our legal guide explains what that means in practice.
Why does a UC San Diego team keep showing up?
UC San Diego's psychedelic research dates to lab work in the 1970s and is now organized as its Center for Psychedelic Research,6 and it has hosted psilocybin trials in pain, anorexia, depression and physician burnout. Our guide to psilocybin research in San Diego lists the local studies we've found and which ones are recruiting.
If you or someone you're with has symptoms after taking a mushroom product, call Poison Control at 1-800-222-1222. Our psilocybin safety guide covers drug interactions and when to call 911.
Sources
- New survey estimates 8 million Americans used psilocybin in 2024. HealthDay, April 24, 2026.
- Lack of regulation raises concerns as psychedelic microdosing gains popularity. KPBS, July 5, 2024.
- Psilocybin exposures reported to U.S. poison centers. Montoy JCC et al., JACEP Open, August 30, 2025.
- Psilocybin exposures among adolescents and young adults reported to U.S. poison centers. Farah R et al., Journal of Adolescent Health, February 26, 2024.
- Active constituents of psilocybin mushroom edibles. van Breemen RB et al., JAMA Network Open, September 11, 2025.
- Psychedelic revolution. University of California (UC San Diego Magazine), November 9, 2023.