Single Dose of MM120 Shows Rapid Anxiety Reduction in GAD, With Maurizio Fava, MD

A single 100 μg dose of MM120 (lysergide D-tartrate, LSD) significantly reduced anxiety symptoms in adults with generalized anxiety disorder (GAD), with improvements appearing as early as day 2 and lasting through 12 weeks, according to a recent phase 2b trial published in JAMA.1 The findings highlight the potential of psychedelic therapy to reshape treatment for a condition affecting roughly 5% of the population.2

Maurizio Fava, MD, chair of the department of psychiatry at Mass General Brigham and member of the MindMed Scientific Advisory Board, discussed the trial results in an interview with HCPLive. He described the top takeaway from the trial: a single-day intervention producing sustained clinical improvement for patients experiencing chronic, debilitating anxiety.

“A single administration creates a lot of excitement,” Fava said. “The results need to be confirmed… [but] they're very exciting, and that's why they end up being published in a top journal like JAMA.”

MMED008, the phase 2b study conducted by MindMed, was a multicenter, randomized, placebo-blind trial evaluating four doses of MM120 (25, 50, 100, or 200 μg) as monotherapy in 198 adults aged 18–74 years with moderate to severe GAD. No psychotherapeutic intervention accompanied the medication.1

The study demonstrated a clear dose-response relationship, with the 100 μg dose producing the most consistent improvements in anxiety symptoms. Lower doses (25 and 50 μg) did not achieve significant clinical benefit despite some adverse events, confirming that the therapeutic effect at 100 μg was not simply due to unblinding from visual disturbances or other acute effects.1

“Interestingly, if you look at their adverse events, the 50-microgram dose, which was not effective clinically, had comparable side effects to the 100 in terms of hallucinations or pseudo-hallucinations,” Fava said. “When people say, ‘Well, these results are because the patients were unblinded by the side effects,’ those on 50 micrograms were unblinded as much as the 100…we can say with confidence that the presence of those side effects that affected almost 75% of those on 50 micrograms versus the 10% of placebo did not was not the cause of the clinical improvement. It was not the unblinding because otherwise 50 would have shown efficacy, but clearly 100 micrograms appears to be the effective dose.”

Fava highlighted the rapid onset of action as a notable feature. Previous trials reported symptom reduction by week four, but the phase 2b results showed improvement as early as day two, with benefits sustained to week 12. This contrasts with conventional GAD treatments such as SSRIs or SNRIs, which require daily use and often bring persistent side effects like sexual dysfunction, weight gain, or gastrointestinal issues.

“If you have side effects, you have side effects. Unless they are transient, you have them all the time,” Fava said. “[Adverse events with] SSRIs don’t go away…you have to take it every day. With psychedelics, you do have side effects on the day of administration…but beyond that…you don't have side effects for the remainder 12 weeks. It's a different treatment paradigm, which patients may see very favorably.”

References

1. Derman C. Single Dose of MM120 (LSD) Shows Lasting Anxiety Reduction in GAD: Phase 2b Results. HCP Live. Published September 4, 2025. Accessed September 4, 2025. https://www.hcplive.com/view/single-dose-mm120-lsd-shows-lasting-anxiety-reduction-gad

2. National Institute of Mental Health. Generalized Anxiety Disorder. www.nimh.nih.gov. Published 2022. https://www.nimh.nih.gov/health/statistics/generalized-anxiety-disorder