The acceptance of psychedelic science in the medical field has been growing over the last decade. We’ve reached the point that psilocybin (for depression) and MDMA (for PTSD) have reached late-stage human trials and are on the verge of clinical approval. However, there is still much to learn about how exactly these psychedelic compounds generate their therapeutic effects.
There are facilities dedicated solely to this task, including Mount Sinai in New York and Johns Hopkins Medicine in Maryland. Researchers from these and other centers have found that:
- DMT could be an effective treatment for anxiety and depression.
- Micro-dosing LSD increases pain tolerance.
- Toad slime may alleviate symptoms of depression.
- Psychedelic drugs overall can improve mental health by helping an individual overcome distressing experiences and accept emotions.
The big question that remains is how?
Psychedelic researchers know that depression is associated with synaptic atrophy in the frontal cortex, so they know that these drugs must be affecting this region. They also know that antidepressants work (improve mood) by reversing these synaptic deficits, thereby increasing neuronal connections in these brain regions.
Therefore, they hypothesize that psychedelics must promote that same kind of neural plasticity. New research coming from Yale University suggests they are correct, at least in mice. The new study reveals the first direct cellular demonstration of a single psilocybin dose inducing neural plasticity in a mammalian brain.
Senior author Alex Kwan, an associate professor of neuroscience and psychiatry at Yale, said:
It may be the novel psychological effects of psilocybin itself that spurs the growth of neuronal connections.
The psychedelic drug psilocybin is a naturally occurring compound found in some mushrooms. For some people, psilocybin’s active compound can produce a profound mystical experience. It was even a staple of religious ceremonies among indigenous populations.
A focused study from our lab to answer one question – what is the extent and time scale of effects of #psilocybin on dendritic architectures in vivo? Led by Lingxiao Shao with help from @ItsClaraLiao @NeilSavalia and others. @YalePsych @YaleNeuro 1/7 pic.twitter.com/wxW3epCuTf
— Alex Kwan 關進晞 (@kwanalexc) February 18, 2021
In a new study, the researchers found that a single dose of psilocybin prompted an immediate and long-lasting increase in connections between neurons in mice. In addition, the drug spurred the rapid growth of neural connections in the frontal cortex, which could be the mechanism responsible for the drug’s antidepressant qualities.
The active compounds in psilocybin increased the animals’ density of dendritic spines – small protrusions found on nerve cells that aid in information transmission between neurons – within 24 hours, and the changes were still present a month later. (Depression and chronic stress are known to reduce the number of these neuronal connections.)
Kwan said:
We not only saw a 10% increase in the number of neuronal connections, but also they were on average about 10% larger, so the connections were stronger as well. 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.
There were even functional and behavioral changes alongside these structural changes: the researchers reported an increase in excitatory neurotransmission in the frontal cortex and stress-related behaviors reduced.
A lot more work will be necessary to understand precisely what is going on here. Still, this study is a great accomplishment as it’s the first to directly demonstrate specific structural neural changes induced by psilocybin in a mammal brain.
