Study finds psilocybin repairs brain cell damage associated with depression

21st July 2021

A new study conducted by Yale University has found that the psychedelic compound psilocybin – a naturally occurring chemical produced by ‘magic mushrooms’ – can repair brain cells damaged by depression. The compound was seen to prompt an immediate and long-lasting increase in connections between neurons.

According to Yale researchers, the administration of a single dose of psilocybin in mice was seen to cause a 10% increase in the number of neuronal connections. Yale’s associate professor of psychiatry and neuroscience and senior author of the paper, Alex Kwan, added that the connections were also “on average about 10% larger, so the connections were stronger as well”.

Kwan, an associate professor of psychiatry at Yale University, said of the research: “My lab has a longstanding interest in studying antidepressants, which started in 2014 with a small pilot grant from the Brain & Behavior Research Foundation.

“We were studying the rapid-acting antidepressant ketamine and found that it has various intriguing effects on changing neuronal connections in the brain. Then about two years ago, we started wondering if the effects generalize to other compounds, so we began working on psilocybin.

“Here we study what psilocybin does in a mouse brain. The data suggest that there is a growth of new neuronal connections in mice after one dose of psilocybin. This happened in the frontal cortex, a brain region important for mood and cognition.”

Past research in the area includes a double-blind placebo study by the Centre for Psychedelic Research at Imperial College London, which demonstrated that the compound was equally as effective in treating depression as conventional antidepressant medication escitalopram when taken in the context of therapy.

Yale’s research showed that psilocybin, as well as ketamine, was able to increase the density of dendritic spines – protrusions found on nerve cells that aid in the transmission of information between neurons. This could make the compounds useful in the treatment of chronic stress and depression, which are known to reduce the number of these neuronal connections.

These increases in neuronal connections were identified using a laser-scanning microscope and were tracked for multiple days in mice. Researchers identified increases in the number of dendritic spines and their size within 24 hours of psilocybin administration. These changes were also still present a month later.

Further, mice subjected to stress were found to show behavioural improvements and increased neurotransmitter activity following psilocybin administration.

Professor Kwan said of the findings: “It was a real surprise to see such enduring changes from just one dose of psilocybin. These new connections may be the structural changes the brain uses to store new experiences.”

Psychedelic mushrooms – popularly referred to as ‘magic mushrooms’ – have been traditionally consumed by societies for millennia, often as a staple of religious ceremonies, and are now largely associated with recreational uses.

Research carried out in the mid-20th century showed that psychedelics may have significant therapeutic benefits for conditions including depression, anxiety, stress and a number of health conditions. The prohibition of these substances put a halt to research into psychedelics, however, the pace in this area is increasingly on the rise.

However, Professor Kwan notes that there remains much more research to be carried out in this area: “One caveat is obviously that this study is done in mice. Ideally, we would like to know what happens in humans, but that is not possible because of the kind of optical imaging that we did, which is very detailed and allows us to see individual sites of neuronal connections but is also invasive and not suitable for humans.”

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