Researchers pinpoint LSD dose that could keep anxiety at bay for weeks

A 100 microgram dose of a pharmaceutical version of the hallucinogenic drug LSD could help stave off the symptoms of severe anxiety for weeks, a study suggests.

Experts said the results are “potentially paradigm-shifting” for people with generalised anxiety disorder (GAD).

A trial explored the effect of MM120, a new pharmaceutically optimised dissolvable LSD tablet, on patients with GAD, a common mental health condition which causes people to feel very anxious about different things.

Symptoms include trouble sleeping, feeling tense, stomach issues, heart palpitations and irritability.

In the UK, GAD is usually treated with talking therapies or medication, typically a type of anti-depressant called an SSRI.

The phase 2b study, led by MM120 developer MindMed and published in JAMA, included almost 200 patients aged 18 to 74 diagnosed with GAD.

Groups were either given single doses of 25 micrograms, 50 micrograms, 100 micrograms or 200 micrograms.

Anxiety levels were measured using a Hamilton Anxiety Rating Scale (HAM-A) score after a week, two weeks, four weeks, eight weeks and 12 weeks.

Clinicians also rated anxiety severity using the Clinical Global Impression-Severity (CGI-S).

The trial found the 100 microgram dose “demonstrated an acute therapeutic benefit” and led to a “statistically significant change in GAD that exceeded the changes seen with lower MM120 doses or with placebo”.

The effect of the drug on anxiety was evident after one day and carried on through to week 12, researchers said.

CGI-S scores on average improved from 4.8 to 2.2 in the 100 microgram dose group, shifting from “markedly ill” to “borderline ill” at week 12, compared with 4.9 to 3.5 in the placebo group.

Most people involved in the study experienced mild to moderate hallucinations on dosing day which had resolved itself in 12 hours.

These effects were more frequent among those who had taken 200 micrograms.

Study author Maurizio Fava, a member of the MindMed scientific advisory board and chair of Mass General Brigham Department of Psychiatry, said: “This study is a true turning point in the field of psychiatry.

“For the first time, LSD has been studied with modern scientific rigour, and the results are both clinically meaningful and potentially paradigm-shifting for the treatment of GAD.”

MindMed is now conducting a number of phase three trials using MM120 on patients with GAD.

Voyage was launched in December 2024, while the second study, known as Panorama, dosed its first patient in January.

Voyage will include around 200 people in the US, while Panorama will be carried out in the US and Europe on around 250 patients.

Data from Voyage is expected in the first half of next year, followed by data from Panorama in the second half of 2026.

In April, MindMed also announced the start of Emerge, a phase three trial looking at MM120 as a treatment for major depressive disorder, with data set to be published in the second half of 2026.