Brain Changes Induced by Psilocybin
A single dose of psilocybin, found in magic mushrooms, seems to trigger structural changes in the brain, based on research involving first-time users of the substance. Scientists observed modifications in brain structure that persisted for at least a month after participants consumed the psychedelic compound.
This study hints at how psychedelics might alleviate conditions like anxiety, depression, and addiction. The structural changes were detected through specialized scans that traced the movement of water in the brain’s nerve pathways, indicating that certain nerve tracts had become denser and more resilient post-consumption. However, the researchers noted that similar alterations are typically seen in aging and dementia.
“It’s quite surprising to observe potential brain structural changes even a month after just one dosage of any drug,” commented Prof. Robin Carhart-Harris, a neurologist at the University of California, San Francisco, who co-authored the study. “While we’re still unsure of what these changes signify, it’s worth mentioning that the participants generally reported positive psychological shifts, including enhanced well-being and mental flexibility.”
Interest in how psychedelics affect the brain has grown, particularly following recent trials suggesting these substances might be effective for various mental health disorders. They are believed to promote flexible thinking, enabling individuals to break free from harmful thought patterns.
In this latest study, conducted by Carhart-Harris and his team at Imperial College London, researchers examined the “entropic brain effect,” where neural activity diversifies during psychedelic experiences, alongside assessing any related psychological improvements.
The study began with 28 healthy volunteers who had never previously taken psychedelics. They initially received a 1mg dose of psilocybin, which was low enough to function as a placebo. Brain activity was then monitored using electroencephalography (EEG) via scalp electrodes.
Over the subsequent weeks, participants underwent numerous assessments to gauge their well-being, psychological insight, and cognitive flexibility. Functional MRI scans and diffusion tensor imaging (DTI) also tracked their brain activity.
A month following the placebo phase, participants were administered a single 25mg dose of psilocybin that could induce a profound psychedelic experience. Throughout the drug’s effects and in the weeks that followed, similar tests and brain monitoring were conducted to observe any changes.
Shortly after consuming the substance, EEG results indicated an increase in brain entropy, suggesting the brain was processing a broader range of information. A month later, DTI scans reflected a decrease in diffusion within nerve tracts connecting the front and middle parts of the brain. This might be due to either the pruning of certain nerve fibers or the development of nerves lacking protective sheaths, though further investigation is required to verify this.
In their report in Nature Communications, the researchers highlighted another significant discovery: participants who exhibited the most substantial surge in brain entropy post-psilocybin were also those most likely to report deeper insights and an improved sense of well-being a month later. This finding emphasizes the connection between cognitive flexibility and enhanced mental health, leading Carhart-Harris to propose a psychobiological therapeutic role for psilocybin.
Prof. Alex Kwan, a neuroscientist at Cornell University, expressed that research in mice indicates psychedelics can rewire neural connections, a form of “plasticity” that may contribute to their therapeutic benefits. The pressing question remains whether similar effects occur in humans. Kwan acknowledged this study’s progress towards that inquiry, providing evidence of enduring structural changes in the brain following psychedelic use. However, he noted that the research involved a limited number of participants and that DTI only offers a partial overview of brain connectivity.
