How many people are actually doing psilocybin therapy?

Psilocybin is a Schedule I controlled substance under US federal law, meaning it has no federally approved medical use and is illegal to possess, use, or distribute under federal jurisdiction. However, two states have created legal frameworks for supervised use: Oregon (licensed service centres operational from 2023) and Colorado (natural medicine healing centres licensed from 2024). Several cities including Washington DC, Denver, Ann Arbor, and Seattle have decriminalised personal possession, meaning enforcement is a low or no priority, but decriminalisation is not the same as legal access. Internationally, psilocybin mushroom truffles are legal in the Netherlands, and psilocybin mushrooms are uncontrolled in Jamaica, making these common destinations for retreat-based experiences. Legal status is changing rapidly: always verify current laws in your jurisdiction before making any decisions.

The evidence is most developed for treatment-resistant depression (TRD), meaning depression that has not responded to at least two antidepressant trials. The Johns Hopkins trial (Davis et al., 2021) found a 71% response rate and 54% remission rate at four weeks, approximately four times better than placebo in comparable trial designs. The COMPASS Pathways trial (Goodwin et al., 2022, N=233) found 29.1% remission at three weeks for the 25mg dose versus 7.6% for placebo. The Imperial College London trial (Carhart-Harris et al., 2021) found psilocybin comparable to the SSRI escitalopram at six weeks, with faster onset and fewer sexual side effects. All trials to date are relatively small, and the field is awaiting larger Phase III confirmatory studies. The FDA has granted psilocybin breakthrough therapy designation for treatment-resistant depression and major depressive disorder.

In a licensed Oregon service centre, a standard session involves three stages. Preparation: one or more pre-session meetings with the facilitator to establish intention, discuss what to expect, and screen for contraindications. The session itself: typically 4-8 hours in a purpose-built space, lying down with eye shades and music, with the facilitator present throughout. The active experience peaks around 2-4 hours after ingestion and typically resolves within 6-8 hours. Integration: one or more post-session meetings to make sense of the experience and translate it into day-to-day life changes. The dose used in therapeutic settings is typically 25mg of synthetic psilocybin, substantially higher than a recreational dose. Facilitators are not permitted to provide talk therapy during the session under Oregon regulations.

In screened populations in controlled settings, serious adverse events are rare. The most common side effects are temporary anxiety or disorientation during the session, nausea, and headache. Psychological distress during the experience occurs in some participants but usually resolves within the session with facilitator support. Rare but serious risks include lasting psychological destabilisation, particularly in people with a personal or family history of psychosis, schizophrenia, or bipolar disorder with psychotic features. These groups are excluded from clinical trials and from Oregon's licensed programme. There is no evidence of physical addiction or organ toxicity at therapeutic doses. Psilocybin should not be combined with lithium or tramadol due to risk of seizure. Mild, temporary cardiovascular effects (elevated blood pressure and heart rate) are common, which is why people with uncontrolled hypertension are typically excluded from trials.

Psilocybin therapy uses a full dose (typically 25mg of synthetic psilocybin) that produces a significant altered state of consciousness lasting 4-6 hours. The therapeutic model relies on this full psychedelic experience, combined with professional facilitation, to produce its clinical effects. Microdosing involves taking roughly one-tenth to one-twentieth of a full dose (typically 0.1-0.3g of dried mushrooms) every few days, with the intent remaining sub-perceptual. The evidence base for microdosing is far weaker. The largest controlled trial (Szigeti et al., 2021) found that microdosing effects did not differ significantly from placebo when expectancy effects were controlled for. Full-dose psilocybin therapy has substantially stronger clinical evidence than microdosing.

The best available estimate is that over 200,000 Americans have participated in some form of guided psychedelic-assisted therapy, including Oregon's legal programme and pre-legalisation clinical trials, research studies, and supervised retreat experiences. Oregon's programme has served tens of thousands of participants since service centres opened in 2023. In Australia, an estimated 2,000 to 5,000 patients have accessed psilocybin through the TGA's Authorised Prescriber pathway. Approximately 9.7 million Americans (3.1% of adults) have used psilocybin at least once in any context, according to NSDUH data, though the vast majority was not in a therapeutic framework. About 15% of US adults report being interested in trying psychedelic therapy, according to YouGov and MAPS survey data.

As of 2026, psilocybin therapy is not covered by any major insurance provider in the United States. Several structural barriers exist: psilocybin remains Schedule I federally, Oregon's programme operates outside the traditional medical model, and the FDA has not yet approved psilocybin as a medication. However, there are signs of movement. Several insurers have begun covering ketamine therapy for depression, establishing a precedent for psychedelic-assisted treatments. The FDA's breakthrough therapy designation could accelerate the approval timeline. If and when FDA approval occurs, insurance coverage would likely follow within two to four years based on historical precedents. Some Oregon centres accept HSA and FSA payments, and advocacy organisations are working to establish patient assistance programmes.

The clinical evidence supports psilocybin therapy for several conditions, with the strongest data in treatment-resistant depression and cancer-related psychological distress. For cancer-related anxiety and depression, both the Johns Hopkins (Griffiths et al., 2016, N=51) and NYU Langone (Ross et al., 2016, N=29) trials showed approximately 80% of participants experiencing clinically significant improvement at six months. For tobacco addiction, a Johns Hopkins trial (Johnson et al., 2014, N=15) found 80% abstinence at six months. Emerging research covers alcohol use disorder, anorexia nervosa, OCD, cluster headaches, and chronic pain, though these applications are at earlier stages. Australia's TGA has specifically approved psilocybin for treatment-resistant depression and PTSD. Psilocybin therapy is not a general wellness tool: the evidence applies to specific conditions treated in specific clinical ways.