What does psilocybin do to your brain health?
Psilocybin shows promising effects on the brain and mood in supervised settings, but the research is still limited and long-term safety has not been well mapped. If you are considering this as a treatment, do so only through a recognised clinical programme.
Psilocybin reduces activity in the central hub regions of the brain, such as the medial prefrontal cortex and the posterior cingulate cortex. That may sound counterintuitive: the substance produces an intense experience, yet measurements taken in 30 healthy volunteers showed lower blood flow and lower activity in those regions. The stronger the decrease in the medial prefrontal cortex, the more intense the psychedelic experience turned out to be.
At the same time, psilocybin stimulates the brain to form new connections. It increases the release of a growth factor that helps create new connections between brain cells, and it activates a system that drives that cell growth. This pattern is seen as a possible explanation for the longer-lasting therapeutic effect. However, this mechanism has been demonstrated mainly in animal research and small clinical studies in humans, so it is not yet an established fact.
In people with severe depression, psilocybin improved cognitive flexibility, the ability to switch between patterns of thinking, for at least four weeks after two treatment sessions. Brain connectivity became more dynamic. An interesting but difficult-to-interpret finding: patients with the greatest brain changes did not necessarily show the most cognitive benefit. The study had no control group, so caution is warranted.
Psilocybin acts via a serotonin receptor that is widely distributed throughout the brain. As a result, it also influences the network that is active when you ruminate or daydream, and the brain's fear centre. The precise way in which this leads to reduced depression is not yet fully understood. A theoretical model proposes that psilocybin temporarily makes the brain more 'loose', allowing entrenched patterns of thought to lose their grip. That is a compelling hypothesis, but it has not yet been directly tested in a clinical setting.
Regarding safety: psilocybin appears to be reasonably safe in a controlled, professionally supervised setting. A review of 34 studies with at least two weeks of follow-up found limited side effects when participants were properly screened and supervised. Outside that setting, risks such as anxiety, disorientation and psychological destabilisation are real. Long-term data in large and diverse populations are still lacking, so how psilocybin plays out over the longer term remains unknown.
This answer is based on a combination of a small study in thirty healthy volunteers using brain scans, an open-label study in 24 depressed patients without a control group, a review of 34 experimental studies, and several theoretical reviews. The researchers behind the review of 34 studies themselves note that the studies are small-scale, often lack a strong control condition and use varying dosages. The mechanistic evidence concerning brain growth and neuroplasticity comes largely from animal research.
Which lifestyle habits protect your brain health over the long term?
Cognitive activities, a plant-based dietary pattern, and regular exercise, preferably in combination, offer the best-supported protection for your brain over the long term. Hard cause-and-effect evidence is still lacking, but the associations are broad and consistent enough to take seriously.
What does air pollution do to your brain in the long term?
Long-term exposure to air pollution, and fine particulate matter in particular, is associated with an increased risk of dementia and faster memory decline. The associations have been demonstrated in multiple human studies, but a direct cause-and-effect relationship has not yet been conclusively proven.
Does olive oil protect your brain against decline?
Extra virgin olive oil as part of the Mediterranean diet has been associated with less cognitive decline in multiple studies, but whether olive oil itself is the protective factor has not been proven. Anyone wishing to support their brain health would do well to follow the complete dietary pattern, not just the olive oil.
What does alcohol do to your brain in the long term?
Long-term heavy drinking demonstrably damages the brain, in part irreversibly. Stopping helps, but after years of heavy use it should always be done under medical supervision.
What can I do to keep my brain healthy as I age?
Combining more exercise with staying mentally active and eating a diet low in sugar and higher in omega-3 fatty acids currently gives you the best chance of a healthy brain. Spermidine and new insights into how the brain cleans itself are, for now, only interesting to follow.
What does a vitamin D deficiency do to your brain?
A vitamin D deficiency is associated with a higher risk of cognitive decline and dementia, but whether correcting it through supplements genuinely protects the brain has not yet been proven. If you are below the threshold, discuss it with your GP.