FDA weighs psychedelic therapy as Compass nears its psilocybin filing: what it means for San Diego

The first psilocybin drug could reach the FDA's desk in full before the end of 2026, and San Diego researchers helped build the case for it. Compass Pathways says its application for COMP360, a psilocybin drug for treatment-resistant depression, is on track to be complete this quarter, weeks after an FDA public hearing on psychedelic therapy drew more than 18,000 registrants. Psilocybin remains illegal in California while all of this plays out.

What happened at the FDA hearing?

On September 14, 2026, the FDA held a public hearing on the potential future therapeutic use of psychedelic drugs, with the VA's health system, SAMHSA, ARPA-H and the National Institute on Drug Abuse as partners. More than 18,000 people registered and about 80 spoke. The agenda covered provider training, safety, insurance and access, and data collection, and written comments were accepted until October 5.^1,2

Speakers didn't agree on much. Psychiatric Times described a field divided over the road to approval, with some speakers citing estimates of serious adverse events in about 4% of trial participants who had existing psychiatric conditions and warning that real-world risk may be underestimated.³ Two months earlier, on July 14, the FDA had finalized its guidance on how psychedelic clinical trials should be designed.⁴

What did Compass's trials show?

Compass ran two Phase 3 trials of COMP360, and UC San Diego in La Jolla was a site for both.^5,6 In July 2026 the company reported 26-week results from the second trial, 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. Serious adverse events occurred at similar rates across arms, and the company reported no new safety findings.⁷

Compass's 2022 Phase 2 trial had reported suicidal ideation or behavior or self-injury in every dose group, including the lowest.⁸ Reporting on the combined Phase 3 safety data in February 2026 said suicidality didn't differ meaningfully between arms and was reported in under 1% of participants.⁹ These are company-reported or secondary summaries; the full peer-reviewed papers will matter.

Where is the FDA application?

The FDA allowed Compass to submit its application in pieces, and in April 2026 awarded COMP360 a Commissioner's National Priority Voucher, which can shorten the review to one or two months once the filing is complete.¹⁰ On August 5, Compass said some modules were in and it was "on track to complete all modules in Q4," with a launch expected in the first half of 2027, "subject to FDA approval and following [DEA] rescheduling."¹¹

As of October 20, Compass hadn't announced that the filing was complete, and no FDA decision date has been made public.

What would approval change in California?

Less than many people expect, but not nothing.

• Psilocybin is still Schedule I today. It remains on the federal Schedule I list, and the April 2026 executive order on psychedelics directed rescheduling reviews without rescheduling anything or setting deadlines.^12,13
• California has a trigger law ready. AB 1021, signed in 2023, lets California health professionals prescribe and dispense an FDA-approved product once it's federally rescheduled, without a new state law. Its author said it doesn't legalize any controlled substance for nonmedical use.¹⁴ Compass says states covering about 90% of U.S. patients intend to reschedule within 30 days of federal action.¹¹
• It would be a prescription drug, not legal mushrooms. An approval would cover COMP360 for its approved use, likely under medical supervision. Possessing mushrooms would still be a misdemeanor under California law, as our legal guide explains.

For now, the legal routes for San Diegans haven't changed: ketamine-based treatment, clinical trials, or Oregon and Colorado's licensed programs. Our psychedelic therapy guide covers each, and our research guide tracks the San Diego trials.