Twelve 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). Most of the participants actively volunteered to take part following presentations by the researchers and media coverage.
Hallucinogenics such as psilocybin can cause unpleasant reactions, including anxiety and paranoia, so it is important to establish whether the drug can be administered safely to people with depression. To investigate the safety and feasibility of using psilocybin for treatment-resistant depression, researchers from Imperial conducted a strictly monitored feasibility study. As this was not a randomised-controlled trial, the patients knew they were receiving the drug and there was no control group to provide comparison either with existing treatments or with no treatment at all.
Previous studies have looked into 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.
It is estimated that 350 million people worldwide are affected by depression. The annual cost of depression in England is thought to be around £7.5 billion. Most people with depression respond positively to treatment using antidepressant medication and cognitive behavioural therapy. But around 20 per cent of those with depression do not respond to treatments and are classified as having treatment-resistant depression.
The study team, from Imperial College London, say this could pave the way for future randomised-controlled trials to establish the efficacy of the compound in treating this form of depression.