What a trip. After a decade of cognitive and functional decline, an 80-year-old patient with advanced Alzheimer’s disease showed remarkable signs of recovery. All it took was a single dose of an experimental hallucinogen to get her speaking more than she had in years — and that’s just the top of the list of her improvements. Alzheimer’s, which affects millions of Americans , gradually destroys memory, thinking skills and the capacity to perform basic tasks. The degenerative disease is generally