Psilocybin Research in UK Advances Amid Regulatory Debate

Research into psilocybin as a treatment for depression is expanding in the UK, with recent clinical trials and policy discussions shaping the landscape for future therapies.

Clinical studies led by COMPASS Pathways, in partnership with King’s College London and South London and Maudsley NHS Foundation Trust, have examined the effects of psilocybin combined with psychological support on individuals with treatment-resistant depression. The Royal Devon University Healthcare NHS Foundation Trust, working with the University of Exeter and Devon Partnership NHS Trust, is also conducting research into the use of regulated psychedelic drugs for major depressive disorder and post-traumatic stress disorder.

Under current UK regulations, psilocybin and most other psychedelics are classified as Schedule 1 controlled substances. This classification indicates that they are considered to have no recognised medicinal use and are subject to strict licensing requirements for research purposes. Researchers and scientists have stated that these restrictions create legal and logistical barriers, including costly licensing and importation processes, which can slow the progress of clinical studies.

In 2022, the UK government stated that it had no plans to reclassify psilocybin to a less restrictive schedule. However, a Home Affairs Committee report published in 2023 recommended urgent rescheduling of psychedelic drugs to allow for larger-scale clinical trials.

What the numbers show

• About 29% of patients receiving 25 mg psilocybin were in remission at three weeks
• At 12 weeks, 20% of the high-dose group remained in remission, compared to 10% in the lowest-dose group
• Oxford meta-analysis included 436 depression patients across seven trials

A phase 2b multicentre trial found that a single 25 mg dose of psilocybin, given with psychological support, led to a greater reduction in depression symptoms over 12 weeks compared to a 1 mg control dose. In this study, remission rates were higher in the group receiving the largest dose, both at three weeks and at the 12-week mark.

An Oxford University meta-analysis of seven clinical trials involving 436 patients with depression found that psilocybin produced greater symptom reduction than placebo or other comparators. The analysis also indicated that the effect was more pronounced in older individuals, those with previous psychedelic use, and those with secondary depression.

While clinical research into psilocybin continues, experts have stated that unregulated recreational use of magic mushrooms can result in mental health risks such as anxiety, trauma, insomnia, hallucinogen persisting perception disorder, depersonalisation, misdiagnoses, and long-term distress.

Industry reaction

The Royal College of Psychiatrists has called for controlled compassionate-use access to psychedelic treatments under strict protocols. The organisation has also stated that current evidence is not yet sufficient to support routine use of these therapies within the NHS.

The Royal College of Psychiatrists has endorsed the use of ketamine and its derivative esketamine for depression in specialist settings, while noting that research into psilocybin and MDMA is still in preliminary stages.

* This article is based on publicly available information at the time of writing.