A small study found that a single 25mg dose of psilocybin produced measurable brain changes that were still visible a month later , along with reported improvements in psychological insight, wellbeing, and mental flexibility. The Guardian reports: Evidence for the changes came from specialized scans that measured the diffusion of water along nerve bundles in the brain. They suggested that some nerve tracts had become denser and more robust after the drug was taken. While the findings are preliminary, the scientists said the opposite was seen in ageing and dementia. "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 the University of California, San Francisco, and senior author on the study.…