An active compound found in the Psilocybe cyanescens mushrooms, called psilocybin, appears to be as effective as a leading antidepressant medication in a therapeutic setting, according to researchers at the Centre for Psychedelic Research at Imperial College London.

The researchers compared two sessions of psilocybin therapy with a six-week course of a leading antidepressant (a selective serotonin uptake inhibitor called escitalopram) in 59 people with moderate-to-severe depression.

Volunteers received an oral dose of the drug in a specialist clinical setting for six weeks, while they listened to a curated music playlist and were guided through their experiences by a psychological support team, which included registered psychiatrists. All volunteers on the study received the same level of psychological support.

Volunteers were then assessed using standardised scales of depressive symptom severity. The main measure, the QIDS-SR-16, was used to gauge depressive symptoms on a continuous scale ranging from 0-27, where higher scores indicate greater depression. At the start of the trial, the mean score was 14.5 for the psilocybin group. But after six weeks, scores reduced by an average of 8.0 points.

Response, defined as a reduction in depression scores from baseline of at least 50%, was seen in 70% of people in the psilocybin group, compared with 48% in the escitalopram group. In addition, remission of symptoms—measured as a score of 0-5 at week six—was seen in 57% of the psilocybin group, compared with just 28% in the escitalopram group.

Overall, those treated with psilocybin—named ‘COMP360’ by its developers—showed marked improvements across a range of subjective measures over a longer period, including in their ability to feel pleasure, and express emotions, greater reductions in anxiety and suicidal ideation, and increased feelings of wellbeing.

“These results comparing two doses of psilocybin therapy with 43 daily doses of one of the best performing SSRI antidepressants help contextualise psilocybin’s promise as a potential mental health treatment. Remission rates were twice as high in the psilocybin group than the escitalopram group,” said Dr. Robin Carhart-Harris, Head of the Centre for Psychedelic Research at Imperial.

“[…] people can clearly see the promise of properly delivered psilocybin therapy by viewing it compared with a more familiar, established treatment in the same study. Psilocybin performed very favourably in this head-to-head.”

However, the researchers warn that patients with depression should not attempt to self-medicate with psilocybin, as the team provided a special clinical and therapeutic context for the drug experience and a regulated dose formulated in laboratory conditions. They stress that taking magic mushrooms or psilocybin in the absence of these careful safeguards might not have a positive outcome.

Read: Magic mushrooms ‘promising’ in depression