How many people are actually doing psilocybin therapy?

Not federally. Psilocybin is a Schedule I controlled substance under US federal law, with no federally approved medical use and no legal possession, use or distribution. Two states built legal frameworks for supervised use anyway, Oregon with licensed service centres from 2023 and Colorado with natural medicine healing centres from 2025. Cities including Washington DC, Denver, Ann Arbor and Seattle have decriminalised personal possession, which lowers the enforcement priority without creating legal access. Truffles are legal in the Netherlands and mushrooms are uncontrolled in Jamaica, which is why both keep appearing as retreat destinations. All of this moves fast, so check your own jurisdiction before deciding anything.

The evidence is strongest for treatment-resistant depression, meaning depression that has not responded to at least two antidepressant trials. Johns Hopkins (Davis et al., 2021) found a 71% response rate and 54% remission at four weeks among 24 people, measured against a waiting-list group rather than a placebo. COMPASS Pathways (Goodwin et al., 2022, N=233) found 29.1% remission at three weeks on the 25mg dose against 7.6% on a 1mg control dose. Imperial College London (Carhart-Harris et al., 2021) found psilocybin and the SSRI escitalopram statistically indistinguishable on its main measure at six weeks, with secondary measures leaning towards psilocybin. Every trial so far is small and the field is waiting on larger Phase III confirmatory work. The FDA has granted breakthrough therapy designation for treatment-resistant depression and major depressive disorder.

A licensed Oregon session runs in three stages. Preparation comes first, one or more meetings with the facilitator to set an intention, cover what to expect and screen for contraindications. Then the session itself, typically 4 to 8 hours in a purpose-built room, lying down with eye shades and music while the facilitator stays present throughout. Peak effects arrive around 2 to 4 hours after ingestion and usually resolve within 6 to 8 hours. Integration follows, one or more meetings to make sense of what happened and turn it into something that changes an ordinary Tuesday. Doses run around 25mg of synthetic psilocybin, well above a recreational dose, and Oregon regulations bar facilitators from doing any talk therapy during the session itself.

Serious adverse events are rare in screened populations in controlled settings. The common side effects are temporary anxiety or disorientation during the session, plus nausea and headache. Psychological distress does happen to some participants and usually resolves inside the session with facilitator support. The rare serious risk is lasting psychological destabilisation, concentrated in people with a personal or family history of psychosis, schizophrenia or bipolar disorder with psychotic features, all of whom get excluded from clinical trials and from Oregon's licensed programme. No evidence exists of physical addiction or organ toxicity at therapeutic doses. Psilocybin must never be combined with lithium or tramadol because of seizure risk, and the mild temporary rise in blood pressure and heart rate is why uncontrolled hypertension usually rules people out of trials.

Psilocybin therapy uses a full dose, typically 25mg of synthetic psilocybin, producing a strong altered state that lasts 4 to 6 hours, and the therapeutic model depends on that full experience combined with professional facilitation. Microdosing takes roughly a tenth to a twentieth of that, around 0.1 to 0.3g of dried mushrooms every few days, deliberately kept below the threshold of noticing. Evidence for microdosing is far weaker. The largest controlled trial (Szigeti et al., 2021) found microdosing effects no different from placebo once expectancy was controlled for. Full-dose therapy has substantially stronger clinical evidence behind it.

Nobody publishes a reliable national count. Oregon's Health Authority reports how many clients its licensed centres serve, Colorado's centres only began sessions in June 2025, and the trials behind the evidence enrolled dozens to a few hundred people each. Far more Americans have taken psilocybin outside any therapy setting than have received it as treatment.

No major US insurer covers psilocybin therapy as of 2026. Three structural barriers hold it there, since psilocybin is Schedule I federally, Oregon's programme sits outside the traditional medical model, and the FDA has not approved psilocybin as a medication. Movement is visible all the same. Several insurers now cover ketamine therapy for depression, which sets a precedent for psychedelic-assisted treatment, and the FDA breakthrough designation could shorten the approval timeline. If approval lands, coverage would probably follow within two to four years on historical precedent. Some Oregon centres accept HSA and FSA payments meanwhile, and advocacy organisations are building patient assistance programmes.

Treatment-resistant depression and cancer-related psychological distress carry the strongest data. For cancer-related anxiety and depression, the Johns Hopkins (Griffiths et al., 2016, N=51) and NYU Langone (Ross et al., 2016, N=29) trials found about 80% and 60 to 80% of participants respectively still clinically improved at around six months. A Johns Hopkins tobacco trial (Johnson et al., 2014, N=15) found 80% abstinence at the same mark. Alcohol use disorder, anorexia nervosa, OCD, cluster headaches and chronic pain are all under investigation at much earlier stages. Australia allows authorised psychiatrists to prescribe psilocybin for treatment-resistant depression, while MDMA is the drug approved for PTSD. None of this makes it a general wellness tool, because the evidence attaches to particular conditions treated in particular ways.