Psilocybin research in San Diego: UC San Diego studies and clinical trials

Most psilocybin research in San Diego happens at UC San Diego, through its Center for Psychedelic Research in La Jolla. Since 2021 the university has run or hosted trials in phantom-limb pain, anorexia, treatment-resistant depression and physician burnout, and VA San Diego has tested MDMA for PTSD. As of October 20, 2026, one local psilocybin trial is listed as recruiting on ClinicalTrials.gov, and it's limited to UC San Diego physicians; the center also lists a phantom-limb brain-imaging study as recruiting.

Taking part in a registered trial is also the only legal way anyone in California can receive psilocybin right now. The drug is still illegal under state and federal law (our San Diego legal guide explains the details), so the studies below are where the science, and any future medical use, is being worked out.

What is UC San Diego's Center for Psychedelic Research?

The center started life as the Psychedelics and Health Research Initiative (PHRI). It grew out of UC San Diego's Arthur C. Clarke Center for Human Imagination after the FDA gave psilocybin Breakthrough Therapy designation in 2018.¹ By 2020 the initiative described its mission as studying "the potential of psilocybin and other related compounds to promote healing and help manage pain," working with the Qualcomm Institute and the departments of anesthesiology and psychiatry.²

In July 2023 the initiative became the Center for Psychedelic Research, a formally approved academic center inside the UC San Diego School of Medicine, with plans to run clinical trials and train scientists.¹ The center's own site describes its focus as the "psychological, physiological, and neural effects, medical value, and transformative properties" of psychedelic states.³

The lab work behind it goes back decades. Psychedelic research at UC San Diego dates to Arnold Mandell's lab around the 1970s, and Mark Geyer was continuously funded by the National Institute on Drug Abuse for 33 years starting in 1983. Adam Halberstadt's mouse "head-twitch" test predicts whether a new compound will be hallucinogenic, and more than a dozen outside companies use his lab to test new compounds.¹

As reported in November 2023, the center was led by Mark Geyer (director), with Adam Halberstadt, Fadel Zeidan, Cassandra Vieten, Tim Furnish, Joel Castellanos and Jon Dean directing its pharmacology, neuroscience, psychology, medical and DMT work.¹ We couldn't confirm whether that roster is the same in 2026; the center's website doesn't list its leaders.

How a phantom limb started it

The initiative's founding story is local. Albert Yu-Min Lin, a UC San Diego alumnus and National Geographic explorer, lost his lower right leg in 2016 and developed phantom-limb pain. A single psilocybin session reportedly relieved it, and the case was written up in the journal Neurocase in 2018 by V.S. Ramachandran and Tim Furnish.^1,2

One case isn't evidence, so the team went looking for a trial. In February 2021 the Steven & Alexandra Cohen Foundation gave $1.3 million for a blinded, placebo-controlled study of psilocybin for phantom-limb pain, using niacin as the placebo.¹ In July 2023 philanthropist Eugene Jhong gave $1.5 million for brain-imaging research on continuous intravenous DMT, led by Fadel Zeidan and Jon Dean.⁴

Which psilocybin studies has UC San Diego run?

Here's every San Diego study we could verify on ClinicalTrials.gov or in published papers, with the status each record showed on October 20, 2026.

Anorexia nervosa (published 2023)

Led by Walter Kaye, with Stephanie Knatz Peck as first author, this open-label study gave 10 adult women with anorexia a single dose of synthetic psilocybin with psychological support. It ran from May 2021 to March 2022 at UC San Diego's Altman Clinical and Translational Research Institute and was funded by Compass Pathways.⁵

The results, published in Nature Medicine on July 24, 2023, found no clinically significant changes in heart rhythm, vital signs or suicidality. Two participants had low blood sugar without symptoms that cleared within 24 hours, and every side effect was mild and short-lived. The authors concluded psilocybin therapy was "safe, tolerable and acceptable" for women with anorexia.⁶ It was a safety study with no control group, so it can't say whether psilocybin treats the illness.

A follow-up Phase 2 study sponsored by Compass enrolled 32 participants at the same La Jolla institute between October 2022 and November 2024. ClinicalTrials.gov lists it as completed; we couldn't find published results.⁷

Phantom-limb pain (results reported, not yet peer-reviewed)

The Cohen-funded pilot (NCT05224336) enrolled 10 people in a double-blind design, with niacin as the placebo. It started in October 2022 and its record now reads "active, not recruiting."⁸

In March 2025, Axios San Diego reported the early results: in the 5 people who got psilocybin, pain severity fell 50 to 75% and the relief grew over the following weeks, while pain in the 4 people who got niacin returned to baseline within two to four weeks. Axios described it as the first randomized controlled trial of a psychedelic for chronic pain. The paper had been submitted for peer review; we couldn't confirm it has been published.⁹ With nine analyzed participants, treat it as a promising signal, not a finding.

A larger follow-up was planned with 25 to 30 people per group.⁹ The center's research page lists a placebo-controlled brain-imaging study of psilocybin for phantom-limb pain as recruiting, with the contact phri-recruitment@ucsd.edu.¹⁰

Physician burnout (recruiting now)

The newest psilocybin study in San Diego asks whether psilocybin-assisted therapy helps doctors with burnout. Led by Cory Weissman, MD, PhD, the open-label Phase 1/2 study (NCT06814522) plans to enroll about 30 UC San Diego physicians, with the federal Advanced Research Projects Agency for Health (ARPA-H) as a collaborator. It began in January 2025 and expects to finish its main data collection in June 2028.¹¹ UC San Diego's trial portal lists it as open to eligible people ages 21 to 70, but it's only for the university's own physicians.¹²

Treatment-resistant depression (Compass Phase 3)

Compass Pathways' two Phase 3 trials of its psilocybin drug, COMP360, both had San Diego sites. COMP005 (258 participants) is complete; its sites included UC San Diego in La Jolla and two private research sites in La Jolla and San Diego. COMP006 (572 registered) is active but no longer recruiting, again with UC San Diego among its sites.^13,14

In July 2026, Compass reported 26-week data from COMP006: of 581 people dosed, 39% of those in the higher-dose arm had a meaningful response at week 6 after two doses, and that response held on average through week 26, with no new safety findings.¹⁵ Those are company-reported numbers. Our news story on the FDA hearing and Compass's filing covers what happens next.

Intravenous DMT brain imaging (not yet recruiting)

This Phase 1 study (NCT07693257), led by Jon Dean, plans to image the brains of about 20 people during a continuous DMT infusion at the Altman institute. Its record, last updated July 9, 2026, listed an estimated September 2026 start and "not yet recruiting."¹⁶

Related UC San Diego studies using ketamine

Two newer UC San Diego trials use ketamine-family drugs rather than psilocybin. KetaMORE (NCT07369089) will pair ketamine-assisted psychotherapy with a mindfulness program for opioid use disorder and is not yet recruiting. A second study (NCT07396220) is testing nasal esketamine with brief cognitive behavioral therapy for people with treatment-resistant depression and suicidal thoughts at UC San Diego Health in 4S Ranch; it's enrolling by invitation.^17,18

What has VA San Diego studied?

VA San Diego's psychedelic work has focused on MDMA for PTSD, led by Dr. Leslie Morland of VA San Diego, the VA's National Center for PTSD and UC San Diego.

• MDMA with couples therapy (NCT05979844). Veterans with PTSD and their partners went through a brief course of cognitive behavioral conjoint therapy, with the veteran taking MDMA in two full-day sessions with the partner present.¹⁹ It enrolled 16 people and finished on November 14, 2025. No results have been posted.²⁰
• MDMA with massed prolonged exposure (NCT06117306). Sponsored by the nonprofit Healing Breakthrough with VA San Diego as a collaborator, this study of about 20 participants started in October 2024 and is active but not recruiting, with completion expected in March 2027.²¹

The VA's Phase 3 psilocybin trial, PIVOT, announced in August 2026, doesn't include San Diego. Our guide for San Diego veterans covers that study and the state's new research funding.

San Diego psychedelic trials: status as of October 20, 2026

Statuses change often. Check the linked record before you contact a study team.

What else have San Diego researchers published?

How many Americans use psilocybin. A UC San Diego and NYU analysis of the 2024 National Survey on Drug Use and Health, published in the American Journal of Psychiatry in April 2026, estimated that about 2.8% of Americans, roughly 8 million people, used psilocybin in the past year. Adults 18 to 25 were 1.4 times as likely to use it as people in their late 30s and 40s. The first author is Dr. Kevin Yang, a UC San Diego psychiatry resident.²² We cover it in more detail in our news story on the study.

Psychedelic-inspired drugs without the trip. A UC Davis-led paper co-authored by UC San Diego's Halberstadt, published in the Journal of the American Chemical Society, used light-driven chemistry to build new compounds that act on the serotonin 5-HT2A receptor. The lead compound fully activated the receptor without causing head twitches in mice, a sign it may not be hallucinogenic.²³ It's early lab work.

We also looked for psychedelic research programs at the Salk Institute, Scripps Research, San Diego State and Sharp HealthCare, and for active San Diego-headquartered psychedelic drug companies. We didn't find any publicly announced as of October 2026. If we've missed one, tell us.

Which California laws affect this research?

Two recent California laws, both with San Diego authors or champions, change how this research gets done.

• AB 1103 (2025), by Assemblymember Chris Ward (D-San Diego), speeds up approvals by the Research Advisory Panel of California, which must sign off on state studies using Schedule I and II drugs like psilocybin and MDMA. It took effect January 1, 2026 and runs until January 1, 2028.²⁴
• AB 113 (2026), a budget bill Governor Newsom signed on September 18, 2026, gives $4.7 million to the California Initiative to Advance Precision Medicine "to support veterans' psychedelic research," with advocates describing the focus as PTSD and traumatic brain injury. The idea grew out of SB 1224, a research-partnership bill championed by Sen. Brian Jones (R-Santee) that stalled in committee in August 2026.^25,26 As of October 2026, we found no university named to run the research.

Neither law makes psilocybin available outside research. They make it easier and better funded to study.

How do you find and join a psilocybin trial in San Diego?

Start with two places:

• UC San Diego's trial portal at clinicaltrials.ucsd.edu/psilocybin, which lists the university's open and closed psilocybin studies.¹²
• ClinicalTrials.gov, the federal registry. Search for psilocybin with "San Diego" as the location and filter to "Recruiting."

Every trial registered on ClinicalTrials.gov has an NCT number. If someone offering a "psilocybin study" can't point you to a registry record, treat it as a red flag.

Expect careful screening. Psilocybin research has long excluded people with a personal or close-family history of psychotic disorders or other severe psychiatric illness, and modern trials keep similar exclusions, including a history of mania.^27,28 Studies also ask about your medications, because some interact with psilocybin (our psilocybin safety guide lists the main ones). In placebo-controlled trials you may get the placebo, and most studies involve several preparation and follow-up visits on top of the dosing session.

What's still unknown?

• Whether the phantom-limb pilot's results will hold up in peer review and in the larger follow-up.
• Whether psilocybin actually improves anorexia, rather than just being safe to give; the published study wasn't built to answer that.
• Which UC campus, if any, will anchor the state-funded veterans' research.
• What the VA San Diego MDMA trials found; no results have been posted.

We'll update this page as results come out. For the regulatory side, follow our San Diego psilocybin news.