Study Finds Brain Structural Changes Persist One Month After Single Psilocybin Dose in Healthy Volunteers

A single 25mg dose of psilocybin, the active compound in magic mushrooms, triggered anatomical changes in the brains of healthy volunteers that persisted for at least one month, according to a new study. The research, conducted on 28 individuals who had never taken psychedelics before, revealed a surge in brain entropy within an hour of ingestion, suggesting the brain processed a greater diversity of information.

Those with the largest entropy spikes were most likely to report deeper psychological insight and better wellbeing weeks later.

The study began with participants receiving a 1mg placebo dose of psilocybin. Scientists then used electroencephalography (EEG) with electrodes on the scalp to measure brain activity, alongside functional MRI scans and diffusion tensor imaging (DTI) to monitor brain structure.

Over the following weeks, volunteers completed tests assessing wellbeing, depth of psychological insight, and flexibility of thinking.

One month after the placebo, the same participants took the full 25mg dose, which elicited a powerful psychedelic experience. During and after this experience, researchers repeated the EEG, functional MRI, DTI scans, and psychological tests. Within an hour, EEG showed the surge in brain entropy, indicating more varied neural activity.

DTI scans one month later detected a drop in diffusion along nerve tracts from the front to the middle of the brain. This drop could result from pruning of some nerve fibers or the growth of new nerves not yet covered with insulating sheaths. The changes aligned with positive outcomes, as participants who experienced the biggest entropy increases reported the most significant improvements in mental flexibility and overall wellbeing.