Psychedelics, like psilocybin (i.e., magic mushrooms) and LSD, have long been associated with mystical visions, ego dissolution, and expanded states of awareness. As far-out and profound as these experiences can be, modern neuroscientists are increasingly grounding them in very concrete biological processes. Research is steadily revealing a clearer picture of how psychedelic therapy can reshape brain function in ways that can support psychological healing and personal growth.
A Quick Primer on the Brain
Your brain is a dense network of about 100 billion neurons, constantly communicating through electrical and chemical signals. These signals are transmitted via molecules called neurotransmitters, which bind to receptors on neighboring neurons. One of the most important neurotransmitters for mood, cognition, and perception is serotonin.
Unconstraining the Mind and Brain: The Serotonin 2A Receptor
Psychedelics work by binding to several receptor types in the brain including over a half-dozen serotonin receptor types, but the serotonin 2A receptor is most critical. If you block this receptor, no amount of psilocybin mushrooms or LSD will make you trip. These receptors are found in parts of the brain that are critical for our ability to reflect on ourselves, imagine the future, and make sense of the world.
When a psychedelic binds to this receptor, it sends the brain into an entirely different mode that is more dynamic, interconnected, and far less constrained. Usual patterns of activity are disrupted and new lines of communication open between brain regions that don’t typically interact. One way to picture this is to imagine your brain as an orchestra. Normally, each instrument follows a strict score and is in sync under the guidance of a conductor. Under psychedelics, the conductor steps aside. Musicians start improvising and tuning into each other in unexpected ways—like flutes riffing with the cellos, new harmonies emerging.
In terms of mental health, this temporary loosening of the brain can break us out of rigid ways of thinking about ourselves and our lives. When supported with care and intention, it can help facilitate insights that lead us towards a more open, connected, and aligned way of being. By creating a temporary state of chaos, a new order can arise.
Boosting Brain Plasticity
Psychedelics also potently boost neuroplasticity, your brain’s ability to change, grow, and adapt. In particular, studies have found that psychedelics stimulate the physical growth of new dendrites, the branches that allow neurons to create more connections with other neurons. Remarkably, some studies have found boosts in plasticity that last over 30 days after a single experience with psilocybin.
This boost in plasticity is thought to create a temporary window of opportunity where the brain becomes more open to change. During this time, it may be easier to shift out of rigid or negative patterns, such as negative self-talk, limiting beliefs, or stuck emotional responses. This may explain why a single psychedelic experience, when combined with the right setting and support, can lead to lasting improvements in mental health. It can also explain why an anxiety and fear-filled ‘bad trip’ can have a deep lasting impact. Plasticity itself is neutral; what you do with it is what matters.
Final Thoughts
By understanding how psychedelics reshape the brain, we begin to see why their responsible use in clinical settings holds so much promise—not just for treating mental illness, but for expanding how we relate to ourselves and the world. As research expands, these once-misunderstood substances may prove to be some of our most powerful allies in healing and personal growth.
Across: Psychedelic Brain Anatomy, acrylic on canvas, 2024, by Brynja Magnusson
