Roughly one in twenty adults in the United States lives with generalized anxiety disorder (GAD), a persistent and excessive form of anxiety that interferes with daily functioning. Conventional medications like Zoloft and Paxil, which boost and stabilize serotonin, reduce symptoms by an average of 1.25 points on the 56-point anxiety scale—insufficient for many patients. At UCSF, neuroscientist Jennifer Mitchell is testing a pharmaceutical form of LSD called MM120 that shows promise in addressing anxiety through a different mechanism: promoting neuroplasticity and easing rigid thought patterns.
In a phase of the study published in JAMA and involving approximately 200 participants with moderate-to-severe generalized anxiety disorder, MM120 significantly outperformed traditional approaches. A single dose reduced anxiety symptoms by five to six points on the anxiety scale beyond the effects of placebo—a difference substantial enough to reclassify moderate GAD as mild in some cases. The drug’s primary mechanism is to promote neuroplasticity in the brain, potentially altering negative thought patterns and increasing communication between brain regions that may address the rigid thinking underlying GAD.
Side Effects and Recruitment Challenges
Participants were carefully monitored by medical staff during and after administration. Side effects were generally mild or moderate and included hallucinations, visual distortions, nausea, and headache, with these effects more prevalent at the highest dosage—which researchers determined was not more effective. Nausea was reduced by restricting participants to a light breakfast and providing proactive anti-nausea medication.
Recruitment presents a unique challenge: while those with disabling GAD symptoms—the population most likely to benefit—are reluctant to leave their homes, these individuals are precisely those least likely to participate in a study requiring in-person clinical visits. Researchers employ highly skilled clinicians who carefully build rapport with potential participants through attentive questioning and observation of body language to establish trust and encourage vulnerability.
This article is an AI-assisted summary. All facts and figures are drawn from the original report: https://www.sciencedaily.com/releases/2025/10/251027023816.htm