Researchers have found that psilocybin, the active compound in magic mushrooms, disrupts a crucial network of brain regions related to introspective thinking, shedding light on the psychedelic effects of the drug.
Individuals who consume magic mushrooms containing psilocybin often experience a distorted sense of space, time, and self. Advocates believe that, in certain circumstances, psychedelic experiences can help alleviate mental distress, supported by some scientific studies. Understanding how psilocybin influences the brain is crucial for leveraging its therapeutic potential.
In a recent study by Washington University School of Medicine in St. Louis, researchers discovered that psilocybin alters a vital network of brain areas linked to introspective activities like daydreaming and recalling memories. This research provides a scientific explanation for the mind-altering effects of the drug and sets the stage for developing psilocybin-based therapies for conditions such as depression and post-traumatic stress disorder.
Co-senior author Nico U. F. Dosenbach, MD, PhD, a neurology professor, remarked, “There’s an immediate significant impact, followed by a lingering effect, which is ideal for a potential medicine. You don’t want the brain networks to be disrupted for days, but you also don’t want them to return to normal right away. A lasting effect is necessary to make a difference.”
The study, published in Nature on July 17, offers a roadmap for researchers to explore the effects of psychoactive drugs on brain function, potentially expediting the development of treatments for various mental disorders.
Psilocybin showed promise as an antidepressant in the 1950s and ’60s, but strict drug regulations hindered further research. Recent regulatory changes have renewed interest in this field.
First author Joshua S. Siegel, MD, PhD, an instructor in psychiatry, stated, “We have significant knowledge about the psychological and cellular effects of psilocybin. However, the impact on the brain’s functional networks, which bridge these two aspects, remains largely unknown.”
To address this gap, Siegel collaborated with Dosenbach, an expert in brain imaging, and co-senior author Ginger E. Nicol, MD, an associate psychiatry professor experienced in clinical trials involving controlled substances. Together, they devised a method to visualize how psilocybin influences individuals’ brain networks and how these changes relate to their subjective experiences.
The researchers recruited seven healthy adults for controlled experiments involving high doses of psilocybin or methylphenidate (Ritalin). Trained experts accompanied each participant to manage potential negative experiences during the psychedelic sessions. Participants underwent multiple functional MRI scans before, during, and weeks after their psilocybin experiences, with four individuals returning for a follow-up six months later.
Psilocybin induced significant and temporary changes in the brain’s functional networks, particularly desynchronizing the default mode network, a group of brain regions active during rest. While this network reorganized after the drug wore off, minor differences from pre-psilocybin scans persisted for weeks. In contrast, participants who received methylphenidate showed no alterations in their default mode network.
Siegel explained, “By briefly desynchronizing this essential system involved in self-awareness, psilocybin induces a psychedelic state. Long-term effects may enhance brain flexibility and promote a healthier state.”
Psilocybin distorted brain networks to such an extent that individuals’ distinctiveness became indistinguishable until the acute effects diminished.
Dosenbach noted, “The brains of individuals under psilocybin appeared more similar to each other than to their sober selves. This validates the common notion of losing one’s sense of self during a psychedelic experience.”
Participants rated feelings of transcendence, connectedness, and awe during the experiment using the Mystical Experience Questionnaire, with the intensity of their subjective experience correlating with the changes in their brain networks.
Nicol underscored the study’s contribution to refining clinical trials for precision medicine in psychiatry, offering insights into who may benefit from specific treatments and dosages.
Nicol, Siegel, and Dosenbach caution against self-medicating with psilocybin based on their research. The drug is not FDA-approved for depression or any other condition, and using it without expert supervision carries risks.
