Psilocybin Clinical Research: Trials and Findings Tracker

Last updated: July 2, 2026 · Data as of January 2026 · Reviewed against the editorial policy

As of January 2026, several hundred clinical studies involving psilocybin are registered on ClinicalTrials.gov, the U.S. registry of clinical research,^[1] and the field is anchored by dedicated centers founded in 2019 at two major universities: Imperial College London's Centre for Psychedelic Research, the first of its kind, and the Johns Hopkins Center for Psychedelic and Consciousness Research, launched with 17 million dollars in private funding.^[2] The U.S. Food and Drug Administration has twice granted psilocybin programs "breakthrough therapy" status — to COMPASS Pathways in 2018 for treatment-resistant depression and to Usona Institute in 2019 for major depressive disorder — a designation that accelerates review of drugs showing preliminary promise.^[3] Randomized controlled trials have been published in the field's most demanding journals, including the New England Journal of Medicine, JAMA, JAMA Psychiatry, and the Lancet group. Yet the total number of participants across all published randomized psilocybin trials remains small — collectively in the hundreds, not thousands — and psilocybin is not an approved medicine anywhere in the United States.

This page tracks the trials that shaped the field and states plainly where the evidence stops. Background on the substance itself is at what is psilocybin; its subjective and physiological effects are described at effects.

The research landscape at a glance

• Hundreds of registered clinical studies involving psilocybin on ClinicalTrials.gov as of January 2026, spanning depression, anxiety, substance use disorders, obsessive-compulsive disorder, anorexia nervosa, cluster headache, and healthy-volunteer basic science.^[1]
• 2 FDA breakthrough therapy designations (2018 and 2019).^[3]
• Phase 3 trials of a synthetic psilocybin formulation (COMPASS Pathways' COMP360) in treatment-resistant depression were underway as of January 2026; no phase 3 program had completed FDA review.
• First federal grant in decades: in 2021 the U.S. National Institutes of Health awarded Johns Hopkins a grant to study psilocybin for tobacco addiction — widely reported as the first NIH grant in roughly half a century for a therapeutic psychedelic trial.^[4]
• 0 approvals: the FDA has not approved psilocybin for any indication. Australia's 2023 authorization for psychiatrist prescribing, described on our legal status page, is a regulatory access pathway, not a completed drug approval based on phase 3 evidence.

Key research institutions and programs

Modern psilocybin research restarted in the early 2000s after a decades-long freeze that followed the scheduling of psychedelics in 1970. A small number of institutions have produced most of the landmark results:

• Johns Hopkins University began its psilocybin program in the early 2000s under Roland Griffiths, published the field's foundational modern study in 2006, and formalized the work in 2019 as the Center for Psychedelic and Consciousness Research.^[2]
• Imperial College London, under Robin Carhart-Harris and David Nutt, ran early neuroimaging studies and the first modern trials in depression, opening the Centre for Psychedelic Research in April 2019.^[2]
• New York University ran one of the two landmark cancer-distress trials (Ross et al., 2016) and later a major alcohol use disorder trial (Bogenschutz et al., 2022).
• COMPASS Pathways (a for-profit company) and the Usona Institute (a non-profit) are the two organizations running FDA breakthrough-designated development programs toward possible approval.^[3]

Landmark trials table

The table lists the published studies most often cited as turning points. Participant counts are as reported in the original papers. All studies used pharmaceutical-grade psilocybin, structured preparation, monitored dosing sessions with trained staff, and follow-up integration — conditions that do not exist outside research and licensed settings.

Source: Wikipsilocybin, compiled from public records. Data as of January 2026.

What the evidence suggests so far

Read together, the published trials support a few careful statements. First, in screened patients, one or two supervised doses of psilocybin combined with psychological support can produce rapid and sometimes durable reductions in depression and anxiety symptoms, with the strongest replication in depression and end-of-life distress.^[7][9][13] Second, signals in addiction — smoking and alcohol use disorder — are promising but rest on one pilot and one mid-sized RCT respectively, which is far short of the evidence base behind approved addiction treatments.^[6][12] Third, effects are not uniformly superior to existing care: the only published head-to-head trial against an SSRI found no significant difference on its primary outcome.^[10] Fourth, larger trials surface more adverse events: the 233-person phase 2b reported treatment-emergent suicidal ideation and behavior in some participants across dose groups, which is one reason phase 3 trials and FDA review exist.^[11]

Researchers consistently emphasize that the drug is only one component. Trials embed dosing in preparation, in-session support from trained monitors, and follow-up integration — a structured version of what harm-reduction literature calls set and setting and trip sitting.

What the research does not show

This section exists because trial results are routinely stretched past what they say. As of January 2026, the published research does not show any of the following:

• It does not show that self-treatment works or is safe. Every positive result above comes from screened participants taking a known, exact dose of pharmaceutical psilocybin with medical backup and trained support present. None of those conditions apply to unsupervised use, and the trials say nothing about it.
• It does not show psilocybin is safe for everyone. Trials exclude people with psychotic disorders, often bipolar disorder, uncontrolled cardiovascular disease, and other risk factors — precisely the people at highest risk outside trials. See risks.
• It does not show that psilocybin is a cure. In the largest trial to date, many responders' depression scores worsened again within three months of a single dose.^[11] Durability is an open research question.
• It does not show superiority over standard treatment. The one direct comparison against an SSRI was statistically inconclusive on its primary endpoint.^[10]
• It does not establish safety of combining psilocybin with psychiatric medications. Trials typically taper participants off antidepressants first. Interaction questions are covered at drug interactions.
• It does not quantify rare harms. A few hundred randomized participants cannot detect uncommon outcomes such as prolonged perceptual changes (see HPPD) or rare severe psychiatric reactions.

Claims that go beyond these boundaries — "psilocybin cures depression," "microdosing is proven" — are addressed on our myths page.

Safety findings inside trials

Within trials, high-dose psilocybin is consistently described as physiologically well tolerated in screened, healthy-enough participants: transient increases in blood pressure and heart rate, headache, and nausea are the common physical effects. The most frequent difficult events are psychological — intense anxiety, fear, or transient paranoia during the dosing session — which trained monitors manage in the room.^[5][11] This is why research protocols and Oregon- or Colorado-style licensed programs both require in-person support; the same logic, applied outside institutions, is the subject of our difficult experiences and emergencies pages. Tolerance to psilocybin also builds rapidly with repeated dosing, which is one pharmacological reason trials space doses weeks apart; see tolerance.

Methodology

This tracker was compiled by the Wikipsilocybin editorial team as follows:

1. Inclusion criteria for Table 1. A study qualifies as "landmark" if it is peer-reviewed, is either the first modern study of its kind or the largest in its indication, and is repeatedly cited in subsequent literature and regulatory discussion. Open-label pilots are included only when they launched a research direction (Johnson 2014) and are labeled as uncontrolled.
2. Sources. Entries are drawn from the original journal publications, ClinicalTrials.gov registry records, and official announcements from the FDA, universities, and sponsors. Secondary media coverage was not used as a source for any trial datum.
3. Reported numbers. Participant counts, dose arms, and outcome statements are taken from the published papers' own abstracts and results sections. Where we were not highly confident of a specific figure, we stated the finding qualitatively rather than inventing precision.
4. Honesty about currency. This page reflects the editorial team's knowledge as of January 2026. Trials report continuously, and phase 3 results in treatment-resistant depression were expected around this period. Each entry — especially the counts of registered trials and the status of phase 3 programs — must be re-verified against ClinicalTrials.gov, journal databases, and FDA announcements before this page is treated as current.

Limitations

• Small total evidence base. Even summed together, published randomized psilocybin trials include fewer participants than a single typical phase 3 antidepressant program. Effect estimates from small trials are unstable and often shrink in larger replications.
• Blinding is weak. Most participants can tell whether they received a high dose of a psychedelic, so expectancy effects likely inflate results — a limitation the field itself discusses extensively.
• Selection effects. Trial volunteers are screened and often highly motivated; results may not generalize to broader clinical populations, and they say nothing about non-clinical use.
• Publication and enthusiasm bias. This is a field with strong advocacy, commercial interests, and media attention. Positive results travel farther than null ones.
• Currency. New results after January 2026 are not reflected. The last-updated and data-as-of dates at the top of this page govern.

Definitions of trial-design terms used on this page (randomization, blinding, active placebo, phase 2b) are in the glossary. How this page is maintained and corrected is described in our editorial policy and about page.