Psilocybin is no longer lurking in the statistical shadows. A UC San Diego–led research team says about 8 million Americans used psilocybin mushrooms in the past year, a number big enough that doctors and public health officials may need to start asking about it as routinely as they do about alcohol.
The estimate, drawn from the 2024 National Survey on Drug Use and Health, suggests roughly 2.8 percent of Americans ages 12 and older used psilocybin in the prior year. It is the first time the federal survey has asked psilocybin-specific questions, and it yielded the first nationally representative past-year snapshot of use. The analysis and its implications were published this month in The American Journal of Psychiatry.
National Estimate and What It Means
To get that figure, researchers examined responses from 58,633 people and calculated a 2.8 percent past-year prevalence, which translates to those 8 million estimated users nationwide. That gives policymakers, clinicians and researchers a concrete baseline for how common psilocybin use currently is.
As detailed in The American Journal of Psychiatry, earlier national surveys generally lumped psilocybin in with other hallucinogens or only asked whether someone had ever used it in their lifetime. That approach blurred present-day patterns, especially as clinical interest and looser local policies have pushed mushrooms further into the mainstream.
Who Is Using Psilocybin
The UC San Diego team found that use was far from evenly spread across the population. Younger adults led the way: people ages 18 to 25 had about 1.4 times the odds of past-year psilocybin use compared with adults ages 35 to 49. On the other end of the spectrum, adults over 50 had roughly one-third lower odds of use.
Men reported higher rates of past-year use than women, and White respondents reported higher rates than Black or Hispanic respondents. According to UC San Diego, the researchers suggest these gaps may reflect both differences in access and cultural or social factors that shape who tries psychedelics and who feels comfortable reporting it.
Mental Health Ties and Polydrug Use
The study also found that psilocybin rarely exists in a vacuum. Past-year psilocybin use was associated with alcohol use disorder, prescription stimulant misuse and recent major depressive episodes. People who used psilocybin were also more likely to report using cannabis and other psychedelics such as LSD, MDMA or ketamine.
The authors are careful to stress in The American Journal of Psychiatry that these are cross-sectional findings. In other words, they show correlations at a single point in time, not cause and effect. Still, the overlap hints at a mix of self-treatment, experimentation and underlying mental health needs that could easily be missed in a rushed clinic visit.
Clinical Caution: Ask and Counsel
Lead author Kevin Yang, M.D., is urging clinicians to start asking about psilocybin use, particularly when they are treating depression.
"When psilocybin is used outside of a clinical setting, the risks look very different," Yang said, pointing to reports of anxiety, paranoia and prolonged psychological distress, along with potential interactions with antidepressant medications.
The UC San Diego summary of the study backs harm-reduction counseling and stronger surveillance. The message is not that every mushroom trip is a crisis, but that clinicians should know who is using, why they are using and what other medications or substances are in the mix.
What to Watch Next
All of this is unfolding as some states move to decriminalize psilocybin or roll out regulated psilocybin services. The authors argue that public health monitoring and harm-reduction outreach need to keep pace with that policy shift, not lag several years behind it.
Coverage of the research, including local reporting by Fox 5 San Diego, highlights how these findings land in real-world settings like clinics, college campuses and community health centers.
One key question the study cannot answer is whether people with depression are turning to psilocybin to self-medicate, or whether psilocybin use itself comes first and is followed by changes in mental health. The authors say it will take longitudinal research and continued surveillance to untangle that timeline and to see how those 8 million annual users fare over the long haul.
