The psychedelic research boom, and what it doesn’t prove yet

A decade ago, suggesting that magic mushrooms might treat depression would have ended a career. Today, universities run dedicated psychedelic research centres, the trials make the front pages and a drug company has started asking the US regulator to approve a psilocybin treatment. Something real has changed. But the distance between “promising results” and “proven treatment” is long, and it is easy to lose in the coverage.

This piece is not an argument for or against psychedelics. It is a guide to reading the research honestly: what the trials have shown, what they have not, and why a result in a clinic says very little about anything outside one.

What the trials actually test

Most clinical studies give psilocybin, or a synthetic version of it, in a prepared room, with trained therapists present before, during and after. Participants are screened carefully, and people with certain personal or family histories of mental illness are usually excluded. The psychological support is part of the treatment, not decoration. When a headline says “psilocybin works”, what was tested was a drug, a therapist, a carefully chosen patient and a controlled setting, all at once.

A result from a supervised clinical setting tells you very little about a weekend with a bag of dried mushrooms.

What the best-known studies found

Two trials published in the New England Journal of Medicine did much to make the field respectable, and both are more modest than their reputation.

In 2021, a team at Imperial College London compared psilocybin with escitalopram, a common antidepressant, in 59 people with long-standing depression over six weeks. On the main measure the trial was designed to test, there was no significant difference between the two. Several secondary measures favoured psilocybin, but the authors noted these were not corrected for multiple comparisons, and concluded that larger and longer trials were needed.

In 2022, a trial of 233 people with treatment-resistant depression found that a single high dose reduced depression scores more than a very low dose after three weeks. A middle dose did not show a significant difference. Sustained response at 12 weeks did not clearly support the early result. Adverse events were reported by 77% of participants, mostly headache, nausea and dizziness, and suicidal thoughts, behaviour or self-injury occurred in every dose group. Again, the authors called for larger and longer trials, including comparisons with existing treatments.

Those bigger trials are now arriving. In July 2026, Compass Pathways, the company behind the 2022 study, told US investors that its two phase 3 trials had met their main goals, and that it expected to complete its application to the US Food and Drug Administration (FDA) by the end of 2026. These are company announcements. Until the full data are published and examined by independent reviewers and regulators, they are a reason to watch closely, not a verdict.

The problems researchers admit to

The most serious weaknesses in this field are not secrets. They are discussed openly in the scientific literature.

• Blinding is hard. A good trial hides who got the real drug. With psychedelics, most participants can tell. A 2021 review found that published psychedelic trials had generally not reported whether blinding worked, and argued that effect sizes are likely overestimated as a result.
• Expectation is powerful. People who sign up for these trials often arrive hopeful, and those who realise they got the active drug may expect to improve. That alone can move a depression score.
• Study design changes the answer. A 2025 meta-analysis found that psilocybin’s effect on depression looked large when compared with an inactive placebo, but was not statistically significant in the small number of trials that used an active drug as the comparison.
• Samples are small. A 2024 Cochrane review of psychedelic-assisted therapy for anxiety and depression in people with life-threatening illness found just six trials, involving 149 people, and rated the certainty of evidence as low to very low.
• Long-term data are thin. Most trials follow people for weeks or months, not years. Depression often returns, and we know little about repeated treatment.

A warning from the MDMA story

If you want to see how strong-looking results can fall short, look at MDMA-assisted therapy for post-traumatic stress disorder. In June 2024, an FDA advisory committee voted 9 to 2 that the data did not show the treatment was effective, and 10 to 1 that its benefits did not outweigh its risks. Members pointed to functional unblinding, expectation bias and selection bias. In August 2024, the FDA declined to approve it and asked for another phase 3 trial.

That does not mean MDMA, or psilocybin, cannot help anyone. It means that enthusiasm, patient stories and large effect sizes are not the same as evidence a regulator can rely on.

Where the law stands in the UK

In the UK, magic mushrooms, fresh or dried, are a Class A drug. According to FRANK, the government-funded drugs advice service, possession can carry up to seven years in prison, and supplying them, even to friends, can carry life. Psilocybin and psilocin are also in Schedule 1 of the Misuse of Drugs Regulations 2001, the most tightly controlled category, for substances considered to have no recognised medical use. Researchers need a Home Office licence to work with them.

That may become easier for researchers. In July 2025, the government agreed in principle with advice from its Advisory Council on the Misuse of Drugs that universities and hospitals could be exempted from needing that licence for research, to be tested through a pilot. It set no timetable, and it did not change the law for anyone else. Some other countries and US states have moved towards regulated access, which is where much of the confusion comes from. A legal change elsewhere does not change the law where you are.

How to read the next headline

There will be many more psychedelic stories, especially if a US approval comes. A few questions help separate news from noise.

• What was it compared with? A placebo pill, a waiting list, a very low dose or an existing treatment all give very different answers.
• How many people took part, and for how long were they followed?
• Did the researchers check whether participants could tell what they had been given?
• Is this a peer-reviewed paper, or a company or university press release?
• Who was excluded? Results from carefully screened volunteers may not apply to people with more complicated health histories.
• Does the story mention side effects, or only benefits?

If you are living with depression that has not responded to treatment, the research is a reason for cautious hope, not a reason to change your own treatment. The NHS advises that antidepressants should not be stopped suddenly, and that any reduction should be planned with your doctor, usually over weeks or months.

This article is for general information and is not medical, legal or financial advice. Laws differ between countries. Read our editorial standards.