We’ll learn about LSD’s potential for treating anxiety in 2026

Two major trials investigating the potential of the psychedelic drug LSD for reducing anxiety are set to conclude in 2026. Scientists are feeling positive after the drug’s success in an earlier-stage trial, which could mean the treatment will be available in the US as early as 2027.

Generalised anxiety disorder is a common condition where people feel very anxious about lots of different things. It is typically treated with antidepressants and talking therapies, but around half of people don’t respond to such treatments.

Other psychedelic drugs like psilocybin and MDMA are already used to treat particularly severe cases of depression and post-traumatic stress disorder in some countries, such as Australia and Switzerland. LSD is increasingly being explored as a mental health treatment, partly because research shows it triggers profound emotional experiences in some people, and it seems to enhance the brain’s ability to rewire itself and form new thought patterns.

In 2025, a landmark trial showed that a single high dose of LSD relieved moderate to severe anxiety for at least three months.

Now, two later-stage trials are building on these results, with findings expected in 2026. Both are made up of about 200 people with moderate to severe anxiety, who will take either LSD as tablets that collectively add up to a 100-microgram dose or placebo pills. Their anxiety levels will be tracked for up to three months after the dosing day.

Then, in a second 10-month phase of the study, all the participants – including those who were initially on placebo pills – will be offered LSD whenever they self-report their anxiety reaching a certain threshold on a standard scale. This will help determine how long effects last from a single dose, says Dan Karlin at biotech company MindMed in New York, who was involved in the 2025 trial and both of the upcoming ones.

The key difference between the two trials is that the second also has a third group of participants on a 50-microgram dose of LSD. The 2025 trial demonstrated that this dose has mind-altering effects, such as hallucinations, but doesn’t reduce anxiety beyond the placebo effect. Including this group should help address a major limitation of most psychedelic trials: that participants can often tell whether they have taken the drug.

Those in the third group may work out that they have taken LSD, but won’t know if it was at the dose needed to reduce anxiety, helping disentangle the placebo effect, says Sandeep Nayak at Johns Hopkins Bayview Medical Center in Maryland, who isn’t involved in the trials.

If they both produce positive results, the Food and Drug Administration (FDA) could approve LSD for treating anxiety in the US as early as 2027, paving the way for potential approval in Europe and beyond, says Karlin.

“If the next trials do anything close to the previous one [in 2025], then it should be enough for the FDA,” says Boris Heifets at Stanford University.

Typically, a 3- to 5-point difference on the anxiety scale used by the team between the placebo and psychedelic groups is considered enough to have a meaningful impact on people’s lives, says Nayak. As the 2025 trial showed a roughly 5-point difference, the next ones stand a good chance of hitting this threshold, although any benefits will have to be weighed up against how long they last and any side effects, he says.

For instance, if the treatment causes transient psychological distress, the FDA may deem that a tolerable side effect, but it probably wouldn’t for longer-term distress, says Nayak. The latter wasn’t seen in the 2025 trial, however.

But even if the approach wins approval, it will probably take several years before LSD becomes widely accessible for anxiety, says Nayak, and even then, it will probably only be used after standard therapies have failed. This is mainly due to practical difficulties, such as the need for clinicians to monitor people for several hours while they are having a psychedelic trip, he says.