Dementia is a degenerative disease that no known drug can completely stop or reverse, despite decades of tests. Now, a historically vilified psychedelic is emerging as a possible new avenue for controlling Alzheimer's symptoms. Neuroscientists around the world are starting to investigate if psilocybin – the psychoactive ingredient in magic mushrooms – can help protect the aging brain. A recent case study in Brazil hints at that tantalizing possibility. It reports that after a patient in her 80s