Today I’d like to start out by examining a question you’ve probably never asked yourself. In evolution, changes come about gradually. Every new change that occurs in a population occurs because it improves the fitness of the population. This leads to a sort of chicken and egg problem, if you have two new features in a population, that depend on each other to function properly. As an example, consider your hormones. Your body produces hormones, but it needs receptors, to pick up those hormones. Why would your body produce testosterone, if it has no way to recognize testosterone? Alternatively, why would it recognize testosterone, if it can’t produce testosterone?

This question applies to your neurotransmitters too. Why does your body produce dopamine, endorphins and all sorts of other neurotransmitters? Surely it must have evolved some method to recognize them, but why would it recognize them, if it can’t produce them? The answer to this question, is found in our environment. Consider the case of glutamate. We use glutamate as a neurotransmitter in our brain. Exposure to glutamate excites a neuron and triggers activity, playing an important role in memory and learning.

However, we also find ourselves exposed to glutamate in food. Protein-rich food contains glutamate, which becomes available for rapid absorption into the blood stream once the proteins begin to break down. For this reason, foods like soy sauce, which consist of broken down proteins, help make our food tastier for us. Long ago, our ancestors would regularly encounter glutamate in food and the body began to evolve to recognize glutamate as an indicator of high quality food. Glutamate excites our neurons and stimulates us to eat more of this high quality food. Thus, before serving as a neurotransmitter that our brain continually produces on its own, glutamate would have served a function as an environmental stimulus.

What then, about the opioid receptors in our brain? Like other mammals, humans produce milk, which serves to nourish a child. A main part of our milk consists of a protein complex known as casein. Casein has a rather unique structure, that serves to release nutrients slowly into the body, thereby effectively nursing a baby. The casein protein can break down however, which leads to smaller protein fragments. These protein fragments are known as casomorphins.

A baby who enjoys drinking the milk of its mother and aggressively demands more of it, is a baby who will survive and become an adult who passes on his or her genes. So, the body of the baby benefits from growing addicted to the milk and feeling happy when exposed to the milk. For this reason, the body has receptors that pick up casomorphins and cause us to grow addicted to the milk. These are the opioid receptors in our brain.

If you ever found yourself wondering why milk products and grains compose such a large part of the human diet, it’s because we choose to produce the kind of food that leaves us addicted. We’re addicted to dairy and cereal grains, as both contain proteins that leave us addicted. Grains have protein peptides that similarly trigger our opioid receptors. It’s possible the opioid receptor is structured the way it is, because we descend from animals that depended on grasses for nutrition. Many plants are toxic, an animal that’s addicted to one harmless source of nutrition will be less likely to eat other plants that can cause birth defects and other harmful effects. Anyone who has grazing animals knows that when they run out of grass to eat, they’ll readily eat all sorts of other plants that may harm them.

Of course, the reverse can take place too. The environment around us can adapt to changes that occur in our brain. Plants, animals and fungi that don’t benefit from being eaten can evolve neurotoxins that abuse the chemistry of our brain. Animals can’t eat pufferfish for example, as the fish contain a highly lethal neurotoxin. Soy produces large amounts of substances with a hormonal influence on our body. Is this a harmless side-effect of some secondary mechanism, or did soy evolve these substances to prohibit animals that ate large amounts of soy from reproducing? This is a controversial question, on which no agreement seems to exist.

A similar principle applies to serotonin and related neurotransmitters. Why do our bodies have receptors that pick up on this chemical? The answer to this question relates to sunlight. Serotonin, dopamine and melatonin are derivatives of an amino acid known as tryptophan. Tryptophan is unique, in the fact that it is very sensitive to sunlight. Exposure to sunlight leads to the production of serotonin from tryptophan, exposure to darkness leads to the production of melatonin from tryptophan. For this reason, our day-night activity cycle is regulated by melatonin and serotonin. If the body produces a lot of melatonin, it recognizes that it’s time to sleep, if it produces serotonin, it recognizes it’s time to be active. Over time, the body thus evolved to make use of various substances derived from tryptophan, as the various derivatives of tryptophan provide useful clues about our environment.

This leads us to the next question: Why do the various psychedelic drugs that interact with the various serotonin receptors in our body, have such an amazing effect on us? What purpose for example, does the 5HT2A receptor serve, that’s responsible for most of the effects caused by LSD, Psilocin, mescaline and other psychedelics? The answer appears to be, that these substances interact with a receptor that’s normally subject to a substance produced naturally by our bodies. This substance, could be considered a kind of endogenous psychedelic.

The substance we are talking about here, is DMT. We have known for a while now, that administering DMT and other substances that trigger similar receptors, protect the brain from severe injury, during periods when very little oxygen is available to the brain. Can you think of a period in time, when all humans are at high risk of suffering from a lack of oxygen in our brain? During birth, we are very much at risk of this condition. We have thus found a possible reason why humans have this 5HT2a receptor that causes the psychedelic effects so many people seek out: The receptor serves to protect our brains from severe damage.

Imagine the following scenario: A child is born during a difficult birth. The child’s body prepares for this disruptive event, by releasing a flood of DMT into the bloodstream. When the child loses access to oxygen, neurons that would normally die now pick up on this chemical substance through the 5HT2a receptor and simply go dormant instead. The brain is thus protected from the kind of severe damage, that would otherwise have occurred during birth.

Where would we want to produce DMT? We would want to produce DMT in the first tissue that has evolved to pick up on the sudden absence of oxygen: The lungs. Studies show that DMT can be produced from serotonin in mammalian lungs, during life threatening events. Ideally, we also want to shut down inflammation in our body upon exposure to this “emergency substance”, as the inflammation triggered by the death of cells leads to a chain reaction of death in other cells. What we find, is that substances that affect the 5HT2a receptor are the most potent anti-inflammatory substances known to science.

So, when we want to understand why the body is so susceptible to the effects of the classical psychedelics, the most likely explanation is because these substances evolved to be released during the event of childbirth. During other severely life-threatening events, DMT also appears to be produced and has the effect of protecting our brain from severe damage. The classical psychedelics serve to protect the brain from severe damage and to stimulate the proliferation of cells to address any damage that may occur. During the psychedelic state, activity in the brain is strongly reduced, which is exactly what we would expect to see occur.

With an understanding of the mechanisms underlying the psychedelic experience, we can better come to understand its purpose. The psychedelic experience can be understood as a period during which the brain is allowed to heal itself. Perhaps most important to understand, is that the psychedelic experience is part of a pattern of rejuvenation. Psychedelics have the effect of rejuvenating the brain. A single strong psychedelic experience, leads to an increase in the personality dimension of openness. This personality dimension gradually declines as we age. To take the Psilocybe mushroom means to rejuvenate our personality to a state decades younger.

Perhaps most interesting is that the psychedelic experience significantly reduces the risk of mental illness. Many studies show a significantly decreased risk of mental health treatment, suicidality and other forms of mental health issues, even after just a single experience. Because chronic inflammation increases as we age, which has the subsequent effect of prohibiting our cells form multiplying, it’s interesting to consider the consequences of the reduction in inflammation that occurs from psychedelics.

We may expect to see an increase in life expectancy if such chronic inflammation is decreased, as it means the body is better able to repair damage that accumulates as we age. Consider that Albert Hoffman, the discoverer of LSD, lived to be 102. During the last few decades of his life, he is said to have microdosed LSD. His friend Ernst Junger, with whom he often took mescaline and LSD, also lived to be 102. The chance of any man born in 1912 in Britain to live to be 100 was 0.3%. In other words, the extreme longevity of these men should be thought of as an interesting anomaly. More interesting however, is the structural difference of the 5ht2a receptor in people who live longer, compared to those who die earlier. The A2A2 version of the gene is associated with increased longevity.

Studies of those who regularly take psychedelics suggest that there are no harmful side-effects. As an example, a study that examined regular Navajo consumers of Peyote, who claimed to have taken Peyote 300 times throughout their lives on average, showed their cognitive performance did not differ from those Navajo who didn’t take Peyote, while their happiness in life was increased compared to non-users. Those who regularly took alcohol in contrast, did suffer from decreased cognitive performance. The evidence we have available today suggests to me that psychedelics will be used at a large scale to address a wide variety of ailments. In fact, I see a potential role for microdosing of psychedelics to address many of the common ailments of aging.