Scientists from the University of California San Francisco and Imperial College London have discovered that psilocybin, the psychedelic compound found in magic mushrooms, may create lasting changes in the human brain after just one dose.
Their study suggests that the drug may temporarily reshape brain activity in ways that improve emotional awareness, mental flexibility, and overall well-being for weeks after the experience.
The findings were published in the journal Nature Communications and are adding to growing scientific interest in psychedelic therapy for mental health conditions such as depression, anxiety, and addiction.
Psilocybin is a naturally occurring psychedelic substance found in certain species of mushrooms. For many years, psychedelic drugs were mainly associated with recreational use and were often viewed negatively. However, scientists have recently started studying these substances again in carefully controlled medical settings.
Researchers are especially interested in whether psychedelics may help people whose mental health problems have not improved with traditional treatments.
The new study focused on healthy volunteers who had never taken psychedelic drugs before. Researchers wanted to understand how psilocybin changes the brain and whether those changes might explain why some people report emotional breakthroughs or improvements in mental health after psychedelic experiences.
The research team used several advanced brain-scanning techniques to examine what happened in the brain before, during, and after taking psilocybin.
One of the most important concepts in the study was something called brain entropy. Entropy in the brain refers to how varied and flexible brain activity becomes. Higher entropy means the brain is producing a wider range of neural activity patterns instead of staying locked into rigid, repetitive patterns.
The researchers believe this temporary increase in flexibility may allow people to think differently, gain new emotional insight, and break out of unhealthy mental habits.
The study involved 28 healthy adults with no diagnosed mental illnesses. Researchers first gave participants a very small 1 milligram dose of psilocybin, which acted like a placebo because it was too low to cause a psychedelic experience.
While participants were under the effects of this small dose, scientists measured their brain activity using electroencephalography, also known as EEG. EEG uses sensors placed on the scalp to record electrical activity in the brain.
Researchers also used functional MRI scans and another imaging technique called diffusion tensor imaging to study brain structure and connectivity.
After several weeks, participants returned and received a much stronger 25 milligram dose of psilocybin. This amount was large enough to create a powerful psychedelic experience.
During the psychedelic session, scientists again monitored brain activity using EEG. Over the following weeks, they repeated the same brain scans and psychological tests.
The results showed clear differences between the low-dose and high-dose sessions.
Within about one hour after taking the larger dose, participants showed much higher levels of brain entropy. In other words, their brains became more flexible and processed information in more varied ways during the psychedelic experience.
Researchers found that people who experienced the largest increases in entropy were also the most likely to report emotional insight the following day.
Many participants described gaining a deeper understanding of themselves, their emotions, and their lives. Researchers believe this psychological insight may be one of the key reasons psychedelics can improve mental well-being.
The effects appeared to continue even after the psychedelic experience ended.
One month later, brain scans showed changes in the structure of neural pathways in the brain. The researchers found evidence suggesting that some brain connections had become denser and more organized.
Scientists noted that these changes appeared opposite to some of the changes normally seen with aging, where brain pathways often become weaker over time.
The researchers emphasized that more studies are needed before scientists fully understand what these structural changes mean. Still, they described the findings as an exciting new clue about how psychedelics may affect the brain long term.
The participants also reported improvements in well-being during the weeks after the experience. Many said they felt more optimistic, emotionally open, and better able to handle life’s challenges.
When researchers tested cognitive flexibility, participants also performed better a month later. Cognitive flexibility refers to the ability to adapt thinking, consider new ideas, and respond more effectively to changing situations.
Almost every participant described the psychedelic experience as one of the most unusual and meaningful states of consciousness they had ever experienced.
Dr. Robin Carhart-Harris, senior author of the study and professor of neurology at UCSF, explained that the findings support the idea that psychedelic experiences may help reveal hidden emotions and thought patterns.
The researchers believe psilocybin may temporarily loosen rigid brain activity patterns that are often linked to depression, addiction, and other mental health conditions.
This may allow people to rethink deeply rooted beliefs, emotional habits, and ways of viewing themselves.
At the same time, scientists caution that psilocybin remains a powerful psychedelic drug and should not be used casually or without medical supervision. The experiences can be emotionally intense, and researchers stress the importance of controlled clinical settings.
The study also had limitations. The participants were healthy volunteers rather than people with mental illness, and the sample size was relatively small. Larger studies are still needed to confirm the findings and better understand long-term safety.
Even so, the research adds to growing evidence that psychedelic therapy may one day become an important medical treatment for certain psychiatric conditions.
Researchers now hope future studies will help determine the safest and most effective ways to use psilocybin in therapy.
If you care about mental health, please read studies about 6 foods you can eat to improve mental health, and B vitamins could help prevent depression and anxiety.
For more health information, please see recent studies about how dairy foods may influence depression risk, and results showing Omega-3 fats may help reduce depression.
The research findings were published in Nature Communications.
Source: University of California San Francisco.
