UCSF and Imperial College London Study Finds Magic Mushrooms Induce Lasting Brain Changes in Healthy Volunteers

UCSF and Imperial College London

25mg Psilocybin Dose

The study measured changes in brain structure and activity using electroencephalography (EEG) and diffusion tensor imaging (DTI). Participants first received a 1mg placebo dose of psilocybin, followed by a 25mg dose a month later, which was sufficient to produce a powerful psychedelic experience. EEG data showed a surge in brain entropy—indicating more varied neural activity—within an hour of the 25mg dose. One month later, DTI scans revealed a decrease in diffusion along nerve tracts in the brain, a pattern opposite to those seen in aging, where neural connections tend to become more diffuse.

Prof. Robin Carhart-Harris

It’s remarkable to see potential anatomical brain changes one month after a single dose of any drug, said Prof. Robin Carhart-Harris, a neurologist at UCSF and senior author of the study. The researchers noted that participants also reported improved wellbeing and mental flexibility, though the exact implications of the structural changes remain unclear. We don’t yet know what these changes mean, but we do note that overall, people showed positive psychological changes in this study, Carhart-Harris said.

Taylor Lyons of Imperial College London

The study’s lead author, Taylor Lyons of Imperial College London, suggested that psilocybin may loosen up stereotyped patterns of brain activity, allowing for new cognitive flexibility. However, the researchers emphasized that the sample size was small and that further studies are needed to confirm the findings. This study comes closer than most to addressing that question, by giving evidence of lasting changes in brain structure after psychedelic use, said Prof. Alex Kwan of Cornell University, who was not involved in the study but commented on its significance.