Psilocybin Research News 2025–2026

Recent Clinical Trial Milestones

The most significant clinical milestone of recent years was the publication of COMPASS Pathways' Phase 2b randomised controlled trial in NEJM Evidence in November 2022. This study enrolled 233 patients with treatment-resistant depression across 22 sites in 10 countries, testing three single-dose levels of COMP360 synthetic psilocybin: 1 mg, 10 mg, and 25 mg. At three weeks post-treatment, the 25 mg group showed a statistically significant reduction in depressive symptoms (MADRS score) compared to the 1 mg control arm. Remission rates at three weeks were 29.1% for 25 mg versus 7.6% for 1 mg — a clinically meaningful difference. The study also documented that adverse effects, though common (including headache, nausea, and dizziness), were transient and manageable under supervised conditions.

The FDA's Breakthrough Therapy designations for psilocybin represent a critical regulatory accelerant. Johns Hopkins University received Breakthrough Therapy designation for psilocybin in the treatment of major depressive disorder in 2019, following an earlier 2018 designation for treatment-resistant depression. These designations — which expedite FDA review and enable closer collaboration between developers and the agency — were milestones that legitimised the clinical research enterprise and accelerated industry investment. As of 2024, at least three companies (COMPASS Pathways, Usona Institute, and Numinus) were advancing Phase 3 preparations or early Phase 3 enrolment for psilocybin-assisted therapy indications.

Usona Institute, a non-profit research organisation, received its own Breakthrough Therapy designation in 2019 for psilocybin in major depressive disorder — distinct from the Johns Hopkins/treatment-resistant depression designation. Usona's PSILO301 Phase 3 trial, which began enrolment in 2023, is notable for using a single 25 mg psilocybin dose administered in a psychotherapy context across multiple sites. Results from this trial, expected in 2025–2026, will be pivotal for FDA approval of psilocybin as a prescription treatment for MDD.

New Therapeutic Indications Being Studied

While depression remains the most advanced clinical indication, researchers are actively investigating psilocybin across a widening range of conditions. Alcohol use disorder has emerged as a particularly promising target. A randomised controlled trial led by Michael Bogenschutz at NYU Langone Health, published in JAMA Psychiatry in 2022, enrolled 93 adults with alcohol use disorder and found that two psilocybin sessions significantly reduced heavy drinking days compared to placebo diphenhydramine — with effects maintained at 32 weeks. The psilocybin group reduced heavy drinking days by 83% compared to 51% in the placebo group, representing a statistically and clinically significant difference that has spurred further trials.

Anorexia nervosa is being studied at UCSF's Translational Psychedelic Research Program (TrPR), led by Natalie Gukasyan and colleagues. A Phase 2 open-label pilot trial (results reported in 2023) found that a single 25 mg psilocybin session was well tolerated and associated with reductions in eating disorder psychopathology scores at one month. This is notable because anorexia has the highest mortality rate of any psychiatric disorder and current treatments are very limited. Several follow-up trials with larger samples and control conditions are now underway.

Cluster headaches — one of the most severe pain conditions known — have a longstanding anecdotal relationship with psychedelics, dating to a 2006 survey by Sewell and colleagues published in Neurology. Controlled research is now catching up: a Phase 2 randomised trial at Yale University and the Entheogen Research, Education, and Community Health (REACH) Institute is evaluating psilocybin for episodic cluster headaches. Additionally, OCD, PTSD, and end-of-life existential distress in non-cancer populations are all active research areas with ongoing or recently completed Phase 2 trials.

Neuroimaging and Biomarker Research

Neuroimaging research has advanced considerably in sophistication since the foundational 2012 Carhart-Harris fMRI study. The ACE (Accept, Connect, Embody) study at Imperial College London, launched in 2022 and continuing through 2024–2025, uses a multi-modal neuroimaging battery — combining fMRI, EEG, MEG, and spectroscopy — to characterise biomarkers of psilocybin's acute and lasting effects with unprecedented resolution. The study aims to identify which neural signatures during the acute experience predict longer-term therapeutic outcomes, a key question for personalised treatment.

The Beckley Foundation, founded by Amanda Feilding, has supported a series of neuroimaging studies examining global brain dynamics under psilocybin. A 2023 analysis using high-density EEG and Lempel-Ziv complexity metrics confirmed that psilocybin produces dose-dependent increases in neural signal diversity — a proxy for information richness in brain activity. A parallel study using 7-Tesla fMRI (higher resolution than standard clinical scanners) mapped psilocybin-induced changes in thalamocortical connectivity with greater anatomical precision than previously achievable, implicating the thalamus as a key relay in the disruption of normal gating of sensory information.

Biomarker research is increasingly focusing on predicting who will respond to psilocybin therapy. Preliminary data from multiple sites suggest that baseline measures of default mode network connectivity, resting-state EEG alpha power, and inflammatory markers (particularly C-reactive protein and interleukin-6) may predict treatment response in depression. If validated, such biomarkers could enable patient stratification and personalised dosing — a significant step toward clinical precision in psychedelic medicine.

Regulatory and Policy Developments

The most consequential regulatory development in the United States has been the implementation of Oregon Measure 110 (now operating as the Oregon Psilocybin Services Act under ORS Chapter 475B). After voters approved legalisation of supervised psilocybin services in November 2020, Oregon's Health Authority developed a regulatory framework that began licensing facilitators and service centres in 2023. By mid-2024, dozens of licensed service centres were operating, offering legal supervised psilocybin sessions to Oregon residents and visitors. This represents the first legal psilocybin framework in the modern United States and is being closely watched as a model for other states.

Colorado followed in November 2022 with Proposition 122, which legalised the supervised use of psilocybin, psilocin, DMT, ibogaine, and mescaline (excluding peyote) for adults 21 and over. Colorado's Natural Medicine Health Act established a regulatory framework similar to Oregon's, with licensed healing centres and trained facilitators. The Colorado framework is broader in scope — covering multiple psychedelics — and its rollout through 2024–2025 has added another real-world data point for regulators and researchers alike.

At the federal level, the FDA's process for reviewing psilocybin as a prescription medicine is continuing through the IND (Investigational New Drug) and NDA (New Drug Application) pathway. The FDA's rejection of MDMA-assisted therapy for PTSD in August 2024 — citing concerns about trial blinding methodology and potential abuse liability — sent an important signal to the psilocybin research community about the evidentiary standards the agency will apply. Researchers and sponsors of psilocybin trials have responded by strengthening functional unblinding controls and expanding safety monitoring in ongoing studies.

Frequently Asked Questions

What did the COMPASS Pathways Phase 2b trial find?

Published in NEJM Evidence in 2022, the COMPASS Phase 2b trial found that a single 25 mg dose of synthetic psilocybin (COMP360) produced significant reductions in treatment-resistant depression symptoms at three weeks compared to a 1 mg control dose. Remission rates were 29.1% vs 7.6%, and the compound was well tolerated under supervised conditions.

What is FDA Breakthrough Therapy designation?

Breakthrough Therapy designation is an FDA program to expedite development and review of drugs that show preliminary evidence of substantial improvement over existing therapies for serious conditions. Psilocybin has received this designation for treatment-resistant depression (2018) and major depressive disorder (2019), enabling closer FDA collaboration and faster review timelines.

Is psilocybin being studied for alcohol use disorder?

Yes. A randomised controlled trial by Bogenschutz et al. published in JAMA Psychiatry in 2022 found that two psilocybin sessions reduced heavy drinking days by 83% at 32 weeks, compared to 51% with placebo in patients with alcohol use disorder. Multiple follow-up trials are now underway to confirm and extend these findings.

What is the ACE study at Imperial College?

The ACE (Accept, Connect, Embody) study uses multi-modal neuroimaging — combining fMRI, EEG, MEG, and spectroscopy — to identify which neural biomarkers during a psilocybin experience predict long-term therapeutic outcomes. It aims to personalise psilocybin therapy by identifying who is most likely to benefit and why.

Is psilocybin legal anywhere in the United States?

Yes. Oregon began licensing supervised psilocybin services in 2023 under the Oregon Psilocybin Services Act. Colorado's Proposition 122 created a similar framework for supervised use of psilocybin and other natural psychedelics, with centres beginning operations in 2024–2025. Psilocybin remains a Schedule I federal controlled substance, but these state frameworks allow supervised legal use within state borders.

What happened with the FDA's MDMA decision and what does it mean for psilocybin?

In August 2024 the FDA rejected MAPS's NDA for MDMA-assisted therapy for PTSD, citing concerns about blinding methodology and abuse liability. This has prompted psilocybin researchers to strengthen their trial designs, particularly around functional unblinding controls, to meet the FDA's evidentiary expectations. The setback has not halted psilocybin development but has added focus on methodological rigour.

Is psilocybin being studied for anorexia nervosa?

Yes. UCSF's Translational Psychedelic Research Program conducted a Phase 2 open-label pilot whose results (reported 2023) found a single 25 mg psilocybin session was well tolerated and associated with reduced eating disorder psychopathology at one month. Given that anorexia has the highest mortality rate of any psychiatric disorder and limited treatment options, this line of research is considered high priority.

What is Usona Institute and what is PSILO301?

Usona Institute is a non-profit psychedelic medicine research organisation that received FDA Breakthrough Therapy designation for psilocybin in major depressive disorder in 2019. Its PSILO301 Phase 3 trial, enrolling since 2023, tests a single 25 mg psilocybin dose with psychotherapy support across multiple sites. Results are expected in 2025–2026 and could lead to the first FDA-approved psilocybin treatment for MDD.

Can psilocybin help with cluster headaches?

Anecdotal reports since a 2006 survey by Sewell et al. in Neurology have suggested that sub-hallucinogenic doses of psychedelics can abort cluster headache cycles. Controlled research is now in progress at Yale University and other sites. Results are preliminary but the signal is considered strong enough to justify formal Phase 2 evaluation.

Are there biomarkers that predict who responds to psilocybin therapy?

Preliminary research suggests that baseline default mode network connectivity, resting-state alpha EEG power, and inflammatory markers (CRP, IL-6) may predict treatment response in depression. If validated in larger studies, these biomarkers could enable patient stratification and personalised dosing — a major step toward precision psychedelic medicine.