A small-scale trial has shown that the psychedelic compound in so-called magic mushrooms can be safely given to patients suffering from depression, paving the way to further trials to assess its efficacy.
In a new study published in The Lancet Psychiatry, researchers at Imperial College London found that the compound psilocybin can be safely tolerated.
Hallucinogenics such as psilocybin can cause unpleasant reactions, including anxiety and paranoia, so the team wanted to establish whether the drug can be administered safely to people with severe, treatment-resistant depression.
The Imperial researchers conducted a strictly monitored feasibility study, although it was not a randomized, controlled trial and was not set up to assess how well it works; that will now be the next step.
In the small study, 12 people with moderate to severe treatment-resistant depression who had not responded to at least two courses of antidepressants were recruited (six men and six women, aged 30 to 64).
The patients received Home Office-approved psilocybin capsules. Blood pressure, heart rate and self-reported intensity of the effects of psilocybin were monitored before and continuously during each of two dosing sessions conducted one week apart. No serious unexpected side effects were reported, according to the authors, but all participants did report temporary anxiety before and during initial drug administration.
Although not assessing efficacy, the study did show that all patients had “some decrease in symptoms of depression” for at least 3 weeks. Seven of them continued to show a positive response 3 months after the treatment, with 5 remaining in remission after 3 months.
The study had some limitations in addition to the small sample size. Previous studies have shown that psychedelics can leave users open to suggestion, which could account for part of the positive outcomes seen here. It was also not possible to control for the psychological support received throughout this study, the authors noted.
But they believe there is a strong safety signal that further proof-of-concept studies can go ahead.
The work builds on previous studies that have explored the potential of using psychedelic drugs for conditions such as end-of-life anxiety, obsessive-compulsive disorder and smoking dependence. Psilocybin acts on the serotonin system, suggesting it could be developed for use in the treatment of depression.
Lead author Dr. Robin Carhart-Harris, from the Department of Medicine at Imperial College London, said in a university news release: “Psychedelic drugs have potent psychological effects and are only given in our research when appropriate safeguards are in place, such as careful screening and professional therapeutic support. I wouldn't want members of the public thinking they can treat their own depressions by picking their own magic mushrooms. That kind of approach could be risky.”