Neurogenesis has become a hot topic in the world of psychedelics in recent years. At Synthesis, we are fascinated to understand whether psychedelics could play a role in the growth and development of human brain cells.
Here’s what we know so far about neurogenesis, and the evidence that psychedelics like psilocybin could be playing a part.
What is Neurogenesis?
Neurogenesis is the growth of new brain cells, called neurons.
The number of neurons in your brain stays pretty stable throughout your life, because unlike most other cells in the body, neurons can’t divide themselves. When you are born, you’ll have most of the neurons you’ll ever need.
But some parts of the brain are capable of growing more neurons in your adult life.
The appearance of new neurons is thanks to neural stem cells. These are special cells that sit in the brain until they are given the signal to turn into neurons.
This process is highly controlled, and neurogenesis only happens in very specific brain areas, within very strict limits. When neurogenesis occurs in these parts of the brain, it is linked with improved learning, forming strong memories, and reversing depression.
Now, there is some evidence to suggest that psychedelics, like psilocybin, could boost natural neurogenesis in the brain. How could this make a difference to our everyday lives? And could this effect be used in psychedelic ceremonies like those at the Synthesis retreat?
How Does Neurogenesis Work in Adults?
Neurogenesis in adults has been linked to three major areas of cognition: learning, memory, and reversing depression.
The mainstream theory is that neurogenesis in one specific area of the brain, the hippocampus, plays a role in how memories develop. It could also be a factor in how we learn new behaviors.
However, we don’t yet know the relative importance of neurogenesis in learning and memory; it may be a contributing factor, but not the most crucial. As well as the growth of neurons, we know that the way neurons make new connections to each other is probably very important in learning and memory, and this is slightly different from neurogenesis.
See our article on neuroplasticity to learn more about how neurons make new connections.
There’s a slightly more robust connection between neurogenesis and depression. People who suffer from depression can sometimes have fewer cells in their hippocampus. It has been hypothesised that boosting neurogenesis could directly fight depression in these people, by helping to increase the number of neurons in the hippocampus.
Some of the most common antidepressants have been shown to boost neurogenesis. This could mean that one of the ways antidepressants work is by helping us to grow new neurons.
So it seems that neurogenesis might be helpful for people suffering from depression or anxiety, while also being involved in memory and learning.
A rat’s hippocampal neuron growing. Credit: Andrew Moore, a researcher and microscopist at the Howard Hughes Medical Institute’s Janelia Research Campus.
Can Psychedelics Boost Neurogenesis?
There is some evidence that different psychedelics could boost neurogenesis, although we’re still in the very early stages of research.
Evidence with LSD and DMT
The synthetic psychedelics LSD and DMT have been shown to help neurons grow in the human brain – but importantly, research shows that LSD and DMT can only boost the growth of already matured neurons, rather than growing brand new neurons.
In this study, led by Calvin Ly at the University of California in 2018, the researchers showed that when rat neurons were grown in the lab, adding LSD or DMT to them helped them grow with more branching connections.
This could mean that these psychedelic compounds may restore areas of the human brain that have been damaged by depression – where the neurons are unhealthy and struggle to form connections. But we’d need studies in humans to confirm that this is the case.
Scientific research shows that classic psychedelics can boost the growth of cortical neurons. Credit: Ly et al (2018)
Evidence with Psilocybin
The psychedelic of choice at the Synthesis retreat, psilocybin, has also been shown to have some potential involvement in neurogenesis.
In one study, led by Briony Catlow at Johns Hopkins University in 2013, psilocybin was given to mice and their brains were investigated for signs of neurogenesis. They found that standard doses of psilocybin (0.1mg/kg) slightly increased the number of new cells growing in the hippocampus of the mice.
These results are preliminary, and we don’t know how they would translate to humans. But they show that it’s likely that psilocybin could boost the growth of new neurons in the hippocampus.
Evidence With Ayahuasca
Some of the components of ayahuasca, a psychedelic brew used in many South American cultures, have been shown to boost the growth of neurons in the lab.
The study, led by Jose Morales-Garcia in Madrid in 2017, used neural stem cells, taken from the brains of adult mice. The cells were grown in the lab, where they naturally formed into balls called “neurospheres.” The stem cells would then start to grow into neurons, and the researchers could track how quickly they grew.
When the cells were grown with harmine, tetrahydroharmine (THH), and harmaline (three of the major components of ayahuasca), the neurospheres grew bigger. The stem cells also looked more like fully-grown neurons in the presence of these ayahuasca substances, suggesting that ayahuasca could encourage neurogenesis.
Again, this is just a study in mice, so further studies are needed to understand how it would look in humans. But it seems as if some of the psychedelic components of ayahuasca could boost neurogenesis by helping neural stem cells turn into fully-grown neurons.
What Can Psychedelics Do for You?
Scientific research in this area is new, and deals with a complex process that we still don’t fully understand. While hard for us to come to any sturdy conclusions about how psychedelics and neurogenesis are connected, the research so far shows us that it’s likely there is a connection. It is possible that psychedelics could boost neurogenesis in some areas of the brain. As neurogenesis is believed to play a role in learning, memory, and depression, it has been associated with a number of psychological benefits.
Whatever role neurogenesis has in the positive effects of psilocybin, the techniques used at Synthesis are proven to be statistically likely to increase wellbeing, decrease depressive symptoms, and improve your sense of connection to nature. If you’d like to learn more about the many ways we use the latest research at Synthesis to craft a transformative psychedelic experience, read more here.