FDA Approves Trials Of Psilocybin For Treatment Of Depression
4 min

FDA Approves Trials Of Psilocybin For Treatment Of Depression

4 min
News Research

Psilocybin, the active ingredient in magic mushrooms, has held a place in medicine since ancient times. Now, the FDA has allowed test trials of psilocybin for the treatment of severe depression.

The US Food and Drug Administration has approved clinical trials of psilocybin for the treatment of treatment-resistant depression. The FDA gave its approval in late-August to Compass Pathways, a self-proclaimed lifestyle sciences company from the UK.

Compass Pathways is currently gathering participants for its study from the UK, Canada, the Netherlands, and, following the FDA’s approval, the US. The study will feature over 200 participants across study centres in each of these countries. Participants need to have been diagnosed with depression and have found little to no relief using multiple antidepressants.

Each patient will be administered a single dose of psilocybin and observed in a room by two therapists. The treatment is expected to last 6 hours, after which Compass Pathways will continue to check in with the participants to gauge the effects of the treatment.

The study is a “phase IIB trial” designed to test the efficacy of the drug. Should it prove effective, phase III trials will look at finding the optimal dose of psilocybin and testing it against placebo and standard treatment with antidepressants.



Compass Pathways already has psilocybin trials underway in the Netherlands (Utrecht and Groningen) and in the UK (London, Manchester, and Newcastle). Other, smaller studies into psilocybin have shown that it can provide both immediate and prolonged relief for depression and anxiety, especially in people who do not respond to regular treatment using antidepressants.

A 2016 study[1] headed by researchers at New York University, for example, showed that psilocybin helped dramatically reduce the symptoms of depression in a small sample of participants who suffered from advanced cancer. The study was double-blind and placebo-controlled.

A 2011 study[2] published in the JAMA Psychiatry journal conducted a similar trial on 12 patients, also with hard-to-treat depression related to an advanced tumour. Each participant underwent two treatment sessions spaced multiple weeks apart; one with a single dose of psilocybin, the other with a placebo. While the researchers used a notably smaller dose of psilocybin than other previous studies, they also noted that psilocybin helped reduce the symptoms of depression.

These aren’t the only studies into the therapeutic potential of psilocybin. Other studies have also examined this for the treatment of addiction, obsessive-compulsive disorders, and more.



How psilocybin acts on the brain isn’t completely clear yet. Some popular media outlets believe it may have to do with the fact that psilocybin can interact with serotonin receptors in the brain. However, numerous studies have shown that the common belief that depression is caused by low levels of serotonin is incorrect.

Some of the leading research into this field comes from the Psychedelic Research Group at Imperial College London. This year, the group began a new randomised, double-blind control trial on psilocybin and its effects on major depression.

Based on research by the Psychedelic Research Group, psilocybin’s positive effect on depression doesn’t have so much to do with serotonin. Instead, researchers at the group believe it has to do with drug’s ability to deactivate parts of the brain involved in ruminating (or repeated negative thinking).

Some of the group's research also suggests that psilocybin might "reset" the brain[3] in a way that helps depressed patients break out of repeated negative behaviours and patterns of thinking. For a more detailed overview of some of the findings of the Psychedelic Research Group, check out this interview with Dr Rosalind Watts as well as this TED Talk by Dr Robin Carhart-Harris.



Psilocybin is the main active chemical in magic mushrooms. It was first isolated in 1958 by Albert Hofmann, the famous Swiss chemist who synthesised LSD. Hofmann isolated the compound from mushrooms grown in France by Roger Heim, a botanist specialised in mycology. The species of mushroom was Psilocybe mexicana.

There are over 200 different types of “magic mushroom” that contain psilocybin. For many ancient cultures, these mushrooms seemed to play a key role in spiritual ceremonies and healing. Cave murals[4] from the Sahara Desert dating back to 9000 BCE, for example, depict horned dancers and god-like figures holding mushrooms, as well as scenes of harvesting and offerings involving mushrooms. 6,000-year-old cave paintings from Villar del Humo, Spain also depict mushrooms, which anthropologists have identified as a type of Psilocybe.

Other evidence from Aztec and Mayan ruins also suggest the spiritual and ceremonial use of psychedelic mushrooms. Old historical accounts from Spanish colonisers of the Americas also recount how these ancient cultures used psilocybin mushrooms in their ceremonies.


Research suggests that psilocybin may have many beneficial effects other than just helping with depression. These include:

Brain cell growth

Psilocybin promoted the growth of healthy brain cells in mice. It also helped the animals overcome “trace fear[5]” (the conditioning that a specific stimulus is threatening or dangerous).

Reductions in OCD behaviour

2006 research from the University of Austin trialled psilocybin on 9 patients with OCD. The study found the drug to be well-tolerated, safe, and effective[6] at significantly reducing obsessive, repetitive behaviours associated with obsessive-compulsive disorder.

Spiritual discovery

Research[7] from Johns Hopkins University in Maryland, USA, found that many users believed their psilocybin experience to be one of the most spiritually compelling experiences of their life. The authors of the study believe it could help reveal many of the mysteries of human consciousness.

New Brain Connections

In his 2017 talk at TEDx Warwick, Robin Carhart-Harris talks about psilocybin’s effects on brain communication. Using brain imaging scans from his research, Dr Carhart-Harris shows that psilocybin can help connect parts of the brain that, in regular consciousness, aren’t connected. He compares this experience to that of the dream state, suggesting it could potentially help us better understand the human subconscious.


As of the end of November, things have improved considerably for the therapeutic use of the humble magic mushroom and its active ingredient.

In a recent move forward for psilocybin research as a therapy for treatment-resistant depression, the American FDA (Food & Drug Administration) designated all ongoing research as "Breakthrough Therapy". This new classification acknowledges that psilocybin has shown significant potential in scientific studies supported by clear clinical evidence.

The Breakthrough Therapy designation was created in 2012. It was designed to facilitate a faster pathway to approval for drugs that showed therapeutic advantages over current treatments for life-threatening and serious health conditions. Not all drugs given Breakthrough Therapy status eventually reach the marketplace. However, it is generally seen as a thumbs up from the FDA, who then help to expedite research into drugs like psilocybin that demonstrate great potential.

The new Breakthrough Therapy classification was given with particular focus on the phase IIB trial presently underway in Europe and North America. This current research is investigating the optimum dosage range for psilocybin when used in the treatment of chronic depression. Earlier research showed positive change in patients with severe depression after one or two doses in a clinical setting.

This is great news for proponents of many Schedule I drugs, which are deemed addictive and of no medical value. Including MDMA—early studies show positive results in the treatment of PTSD—and cannabis, a number of therapeutic compounds are proving their potential in the treatment of a litany of ailments.

FDA approval is often followed by the rescheduling of drugs away from Schedule I by the DEA. This leads to less roadblocks in research and clinical trials, and the removal of stigma in the eyes of the general populace. However, unlike psilocybin, the DEA remains stubborn regarding cannabis and MDMA scheduling at present.

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Steven Voser

Written by: Steven Voser
Steven Voser is an Emmy Award Nominated freelance journalist with a lot of experience under his belt. Thanks to a passion for all things cannabis, he now dedicates a lot of his times exploring the world of weed.

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We are not making medical claims. This article has been written for informational purposes only, and is based on research published by other externals sources.

External Resources:
  1. SAGE Journals: Your gateway to world-class journal research -
  2. JAMA Network | Home of JAMA and the Specialty Journals of the American Medical Association -
  3. Psychedelic Science Summit - Austin, Texas -
  4. -
  5. Effects of Psilocybin on Hippocampal Neurogenesis and Extinction of Trace Fear Conditioning - PubMed -
  6. Safety, Tolerability, and Efficacy of Psilocybin in 9 Patients With Obsessive-Compulsive Disorder - PubMed -
  7. Johns Hopkins Medicine, based in Baltimore, Maryland -

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