BackgroundAdvanced Alzheimer’s disease (AD) is generally regarded as a stage of irreversible functional decline. Psilocybin is known to transiently alter large-scale brain network dynamics and to induce plasticity-related mechanisms in preclinical models, yet clinical data in advanced dementia remain lacking.Case presentationWe report the case of an octogenarian Japanese-American woman with a 10-year history of Alzheimer’s disease, including 5 years of marked hypofunction and predominantly monos