In brief
- A randomized, placebo-controlled phase 2b trial published in JAMA (2025) evaluated a single dose of LSD (MM120) in 198 people with generalized anxiety disorder.
- Doses of 100 and 200 µg reduced anxiety in a statistically significant manner compared to placebo at 4 weeks, with improvements maintained through week 12.
- The results are promising but preliminary: moderate sample size, short follow-up, and administration in a controlled clinical setting with professional support.
A single session of LSD, administered under clinical conditions, produced a reduction in anxiety that persisted three months later in people with generalized anxiety disorder (GAD). This is the conclusion of a phase 2b trial published in JAMA in late 2025, one of the first modern, randomized, placebo-controlled studies to rigorously examine the effect of lysergide on this disorder.
The study
The paper, authored by Reid Robison and colleagues, was published in JAMA in 2025 (vol. 334, no. 15). It is a phase 2b clinical trial: multicenter, double-blind, and placebo-controlled—the design considered standard for assessing efficacy before moving to large-scale phase 3 trials. A total of 198 adults with a diagnosis of generalized anxiety disorder participated (194 were included in the analysis). Each person received a single administration of MM120—a pharmaceutical form of lysergide tartrate, i.e., LSD—in one of four doses (25, 50, 100, or 200 micrograms) or a placebo. The primary endpoint was the change in the Hamilton Anxiety Rating Scale (HAM-A) at four weeks, a classic instrument for quantifying the intensity of anxiety symptoms.
It is worth highlighting a key design feature: this was not continuous treatment, but a single intervention performed in a monitored clinical environment with professional support during the session. That architecture of the context—the so-called setting—is part of the experiment and cannot be separated from its results.
What was found
The trial met its primary objective: there was a dose-response relationship. The low doses (25 and 50 µg) did not differ from the placebo, but the two highest doses did. At four weeks, the 100 µg dose reduced the HAM-A score by 5.0 points more than the placebo (95% CI: −9.6 to −0.4), and the 200 µg dose reduced it by 6.0 points (95% CI: −9.8 to −2.0), both with statistical significance. The authors identified the 100 µg dose as having the best balance between efficacy and tolerability.
The improvement was not fleeting. At twelve weeks, 65% of those who received 100 µg responded to treatment (a drop of at least half on the anxiety scale), compared to 30.8% in the placebo group. Furthermore, 47.5% achieved remission—symptoms practically absent, with a HAM-A of 7 or less—compared to 20.5% with the placebo. Regarding safety, adverse effects were concentrated on the day of dosing and were those expected with LSD: visual perceptual changes (around 92–100% with the high doses), nausea, and headache. The vast majority resolved by the end of the session, and no emergence or worsening of suicidal ideation or behavior was recorded.
What it means (and what it doesn’t)
The numbers are striking, and it is legitimate to be cautiously optimistic. That a single session can move the needle on an often-chronic disorder, and that the effect remains present twelve weeks later, is data that deserves attention. But honesty means also looking at the limitations, of which there are several.
First, it is still an early-phase study. Nearly two hundred people is a respectable sample for a phase 2b, but modest for drawing firm conclusions about large-scale efficacy and safety. Second, the follow-up was short: twelve weeks tells us little about what happens at six months or a year. Third, and perhaps the most delicate point in these trials, blinding is difficult to guarantee: when 90% of the active group experiences obvious visual effects, both the participant and the evaluator can intuit what they received, which can inflate the measured response. Fourth, everything took place in a clinical setting with supervision: none of this describes or endorses self-administration, where controlled dosing, professional support, and safety nets are absent.
The development context also matters as an objective fact: MM120 is already moving toward phase 3 trials (the Voyage and Panorama studies), which will be the ones to confirm or correct these signals. Legally, lysergide remains a controlled substance in most countries; its use in research is conducted under specific authorizations. We mention this without moralizing: it is simply the framework in which this science currently takes place.
In summary, the trial provides real, high-quality evidence that LSD, in a very specific format and context, could help with generalized anxiety. It is neither a miracle nor a cure; nor is it a threat that must be demonized. It is one more piece—solid, but preliminary—in a field that is beginning to reopen after decades of paralysis.
Source
- Robison R, Barrow R, Conant C, et al. Single Treatment With MM120 (Lysergide) in Generalized Anxiety Disorder: A Randomized Clinical Trial. JAMA, 2025; 334(15):1358–1372. doi:10.1001/jama.2025.13481
Educational content written from a harm reduction perspective and with respect for individual freedom. It is not a substitute for advice from a healthcare professional and is not intended to encourage or condemn any drug use.
