A single dose of psilocybin, the active psychedelic compound in magic mushrooms, triggers significant physical alterations in the brain that can persist for up to a month, according to a study led by researchers at the University of California, San Francisco and Imperial College London.
This groundbreaking study, published in Nature Communications, involved healthy adults who had never previously used psychedelics. While none of the participants had any diagnosed mental health issues, the results may provide insights into why psilocybin shows potential for treating depression, anxiety, and addiction.
The researchers focused on temporary spikes in the brain’s “entropy,” referring to the diversity and unpredictability of neural activity. Their findings imply that this enhanced diversity in brain activity could foster psychological insights, indicating that the psychedelic experience itself may be crucial for psilocybin’s long-term benefits.
Participants who experienced greater increases in entropy shortly after the high-dose ingestion reported more emotional insights the following day. Those who noted more insights also tended to indicate improved well-being one month later.
“Psychedelic means ‘mind-revealing’ or making the mind visible,” stated lead author Robin Carhart-Harris, Ph.D., Ralph Metzner Distinguished Professor of Neurology at UCSF. “Our data reveal how experiences of psychological insight correlate with the entropic nature of brain activity and how both contribute to improvements in mental health. It suggests that the connection between psychedelic experiences and brain function is a significant factor in the effectiveness of psychedelic therapy.”
Examining the Effects of Psilocybin on the Brain
The research team employed multiple methods to assess brain activity, connectivity, and structure. Measurements were taken before the administration of psychedelics, at the peak of the experience, and again one month later.
All 28 volunteers in the study were free from diagnosed mental health conditions, allowing broader testing than would be feasible with clinical patients.
Initially, each participant received 1 mg of psilocybin, treated as a placebo. Brain activity was monitored using electroencephalography (EEG), which captures electrical signals through electrodes on the scalp.
Over subsequent weeks, researchers evaluated psychological insight, well-being, and cognitive performance. They also utilized functional MRI (fMRI) to study brain activity and diffusion tensor imaging (DTI) to explore connections between different brain regions.
One month post-placebo, participants consumed 25 mg of psilocybin, known to produce a profound psychedelic experience. Brain activity was again recorded with EEG during the experience, followed by the same psychological and imaging assessments over the next several weeks.
This design enabled researchers to compare the effects of a full dose of the psychedelic to those observed after the placebo.
Psilocybin and Increased Brain Entropy
Within an hour of ingesting the 25 mg dose, EEG recordings indicated a rise in brain entropy. This suggests that the brain generated and processed a broader range of information under the influence of psilocybin.
DTI assessments conducted a month later revealed denser and more complete nerve tracts, contrasting with changes typically associated with aging, where neural pathways become less dense.
While further research is necessary to interpret these structural findings, the results serve as a groundbreaking indication that psychedelics can effect lasting brain changes.
Sustainable Improvements in Insight and Well-Being
The day after taking 25 mg of psilocybin, 27 of the 28 participants described it as the “most” unusual state of consciousness they had ever experienced, while the remaining individual ranked it among their top five most unusual life experiences.
Participants reported significantly enhanced psychological insights following the 25 mg dose compared to the 1 mg placebo. Moreover, improvements in well-being appeared two and four weeks post-high dose, with responses like “I feel optimistic about the future” and “I am coping well with my problems.”
One month after the study, participants excelled in tests measuring cognitive flexibility, which assesses the ability to adapt and respond to changing information.
“Psilocybin seems to relax fixed patterns of brain activity, enabling individuals to adjust rigid thinking,” remarked Dr. Taylor Lyons, a researcher at Imperial College London and lead author of the study. “Notably, these changes can be correlated with insights that enhance well-being, making them particularly compelling.”
Potential Benefits of Psychedelic Experiences
Participants who experienced the greatest initial increases in brain entropy following psilocybin ingestion were also more likely to report greater insights the next day. These insights later correlated with enhanced well-being one month afterward, leading researchers to conclude that psychological insights play a critical role in promoting well-being.
This research could ultimately guide clinicians in optimizing psilocybin treatments for mental health conditions, potentially pinpointing doses that induce sufficient brain entropy to generate meaningful insights without leading to excessively intense experiences.
“We already knew that psilocybin aids in the treatment of mental illness,” Carhart-Harris remarked. “Now, we have a clearer understanding of how to optimize this process.”
Authors: Additional authors from UCSF include Manesh Girn, PhD, Hannes Kettner, and Adam Gazzaley, MD. Refer to the paper for a complete list of authors.
Funding: This research was supported through charitable donations to the Center for Psychedelic Research, Imperial College London, the Alex Mosley Charitable Trust, and the Beckley Foundation. Carhart-Harris is backed by a Ralph Metzner Distinguished Professorship and funds to the Department of Psychedelics at Neuroscape at UCSF, as well as additional philanthropic support for the Carhart-Harris Institute.
Source: www.sciencedaily.com