Is psychedelic medicine finally ready to live up to the hype? Yesterday, from the largest clinical trial of psilocybin for depression to date. They suggest that, while psilocybin therapy is far from a panacea, it can help some people for whom current medicines are ineffective.
The study was led by Compass Pathways, a UK-based company that holds patents for two synthetic formulations of psilocybin, the active ingredient in magic mushrooms. It involved 233 people with treatment-resistant depression, meaning to be eligible they had to have tried two other treatments without success.
The participants were randomly assigned one of three doses: 1, 10 or 25 milligrams. The 1 milligram dose is considered so small that it is effectively a placebo, but it meant all participants knew they would get psilocybin, creating an expectation of some benefit. All were given psychological support before, during and after a single dosing session.
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In the 25 milligram group, 36.7 per cent of patients had improved depression severity scores three weeks after dosing, and 24.1 per cent were still responding after 12 weeks.
These numbers may seem low: in , 70 per cent of patients who received psilocybin therapy showed a response at six weeks. But that study was smaller and involved two doses of the drug.
鈥淭here is a general trend in science that the first small studies have huge effect sizes, and as you study more, they get less and less. The hope that we all have is that it doesn鈥檛 disappear,鈥� says at King鈥檚 College London, who worked on the Compass study. 鈥淲e need to do a lot more work looking at the duration of the effect and see how it pans out in the clinic, but the fact that a group has a persistent benefit to 12 weeks, to my mind, is really heartening.鈥�
The contrast with conventional antidepressants is stark. People usually need to take daily pills for several weeks before seeing an effect, and if they stop taking them, they risk relapsing.
Psychedelics present an alternative approach. Young suggests people may have a one-off treatment, see a benefit that lasts for weeks or months, then return for occasional top-up treatments if needed.
Depression worldwide, many of whom don鈥檛 benefit from existing treatments. There is a real need for alternatives, especially ones that lead to fast results.
A form of ketamine, a drug with psychedelic effects but a different mode of action, has already been approved by the US Food and Drug Administration (FDA). Backed by a growing number of pharmaceutical companies, as well as non-profit organisations, psilocybin looks like it could follow. A in the US involving 100 people with major depressive disorder is due to report results next year. Compass plans to begin the final stage of its clinical tests next year, and the FDA has already designated it a 鈥溾��, which could accelerate the approval process.
Taken together, these developments suggest psychedelics could soon be seen as credible mental health treatments, at least for some. 鈥淲e have to be cautious about overpromising, because they don鈥檛 work for everyone,鈥� says at the University of Exeter, UK. 鈥淚 think they will provide a really important and novel contribution to psychiatry.鈥�
