"Drugs with psychedelic effects, like psilocybin, LSD, MDMA, & cannabis, may help protect the brain from some aspects of aging.
A recent survey of 3,294 US adults, aged between 42 & 92, has found that those who reported using a hallucinogen of any kind in the past year show fewer depressive symptoms & more favorable changes to their higher-order brain functions.
Compared to those who did not use psychedelics, those who did scored higher on tests conducted over the phone which assessed inductive reasoning, verbal fluency, working memory, processing speed, attention switching, & inhibitory control." https://www.sciencealert.com/older-people-who-use-psychedelics-show-fascinating-brain-functions