Enlarge / New research suggests how psychedelics can trigger rapid and lasting change.
The human brain can change – but usually only slowly and with great effort, for example when learning a new sport or foreign language or when recovering from a stroke. Learning new skills correlates with changes in the brain, as shown by neuroscientific studies in animals and functional brain scans in humans. If you’ve mastered Calculus 1, something in your brain is probably different now. Additionally, motor neurons in the brain expand and contract depending on how often they are used—a neural reflection of “use it or lose it.”
People may wish their brains could change more quickly – not just in learning new skills, but also in overcoming problems such as anxiety, depression and addictions.
Doctors and scientists know that there are times when the brain can make rapid and lasting changes. These most often occur in connection with traumatic experiences and leave an indelible impression on the brain.
But just as quickly, positive experiences can occur that change your life in a positive way. Think of a spiritual awakening, a near-death experience, or a feeling of awe at nature.
Social scientists refer to events like these as psychologically transformative experiences or crucial mental states. For the rest of us, they are forks in the road. Presumably, these positive experiences quickly change some of the “wiring” in the brain.
How do these rapid, positive changes come about? It appears that the brain has a way of facilitating accelerated change. And here’s where it gets really interesting: psychedelic-assisted psychotherapy appears to utilize this natural neural mechanism.
Psychedelic-assisted psychotherapy
Those who have had a psychedelic experience usually describe it as a mental journey that cannot be put into words. However, it can be thought of as an altered state of consciousness with perceptual distortions, an altered sense of self, and rapidly changing emotions. There is probably a loosening of higher brain control, allowing deeper thoughts and feelings of the brain to come into consciousness.
Psychedelic assisted psychotherapy combines the psychology of talk therapy with the power of a psychedelic experience. Researchers have described cases in which subjects reported profound, personally transformative experiences after a six-hour session using the psychedelic substance psilocybin in conjunction with psychotherapy. For example, patients worried about advancing cancer quickly felt relief and an unexpected acceptance of the impending end. How does this happen?
Research suggests that new skills, memories and attitudes are encoded in the brain through new connections between neurons – much like branches of trees growing towards each other. Neuroscientists even refer to the growth pattern as tree formation.
Using a technique called two-photon microscopy, researchers can observe this process in living cells by tracking the formation and regression of spines on neurons. The spines are half of the synapses that allow communication between one neuron and another.
Scientists have hypothesized that lasting spinal formation can only be achieved with concentrated, repetitive mental energy. However, a laboratory at Yale recently documented the rapid formation of spines in the frontal cortex of mice after a dose of psilocybin. Researchers found that in mice given the mushroom-derived drug, spine formation increased by about 10 percent. These changes occurred when examined one day after treatment and persisted for over a month.
Enlarge / Tiny spines along a neuron’s branches are a crucial factor in how one neuron receives a message from another.
A mechanism for psychedelic-induced changes
Psychoactive molecules change brain function primarily through receptors on nerve cells. The serotonin receptor 5HT, which is known to be altered by antidepressants, comes in different subtypes. Psychedelics like DMT, the active chemical in the herbal psychedelic ayahuasca, stimulate a receptor cell type called 5-HT2A. This receptor also appears to mediate the hyperplastic states when a brain changes rapidly.
These 5-HT2A receptors that DMT activates are not only on the cell surface of the neuron, but also inside the neuron. Only the 5-HT2A receptor inside the cell enables rapid changes in the neuronal structure. Serotonin cannot penetrate the cell membrane, which is why people do not hallucinate when taking antidepressants such as Prozac or Zoloft. The psychedelics, on the other hand, penetrate through the outside of the cell and stimulate the 5-HT2A receptor, thereby stimulating dendrite growth and the formation of spines.
This is where this story comes together. In addition to being the active ingredient in ayahuasca, DMT is an endogenous molecule naturally synthesized in the mammalian brain. Therefore, human neurons are capable of producing their own “psychedelic” molecule, although probably in tiny quantities. It’s possible that the brain uses its own endogenous DMT as a tool for change – such as the formation of dendritic spines on neurons – to encode crucial mental states. And it’s possible that psychedelic-assisted psychotherapy utilizes this naturally occurring neural mechanism to facilitate healing.
A word of caution
In her essay collection “These Precious Days,” author Ann Patchett describes taking mushrooms with a friend who was suffering from pancreatic cancer. The friend had a mystical experience and felt a deeper connection to her family and friends. Patchett, meanwhile, said she spent eight hours “chopping up snakes in a pitch-black lava cauldron at the center of the Earth.” It felt like death to her.
Psychedelics are effective and none of the classic psychedelics such as LSD are yet approved for treatment. The U.S. Food and Drug Administration approved ketamine in conjunction with an antidepressant in 2019 to treat depression in adults. Psychedelic-assisted psychotherapy with MDMA (often called Ecstasy or Molly) for post-traumatic stress disorder and psilocybin for depression is in Phase 3 trials.
Edmund S. Higgins, Associate Professor of Psychiatry and Family Medicine, Medical University of South Carolina. This article is republished from The Conversation under a Creative Commons license. Read the original article.