Cannabis and Brain Aging: Can weed keep your brain young?

About this episode

Can weed protect your brain as you get older? We unpack a study linking lifetime cannabis use to larger brain volumes and better cognitive test scores in older adults—and investigate how those findings became headlines urging readers to “pass the pot to grandma.” Along the way, we explore collapsing categorical variables, confounding, clinically versus statistically significant results, multiple testing, and how a press release subtly changed a story. We also meet permanently stoned mice, learn about Carl Sagan’s surprising connection to cannabis research, and discover how a single missing word can change the entire meaning of a study. Statistical topics • Categorical variables • Confounding • Effect size • False discovery rate • Healthy volunteer bias • Measurement error • Multiple testing • Observational studies • Recoding variables • Science communication • Statistical vs practical significance Methodologic Morals • “Always follow the chain from data to result to conclusions and pay attention to the words along the way.” • “Huge samples can give tiny differences delusions of grandeur.” References • Guha A, Fu Z, Calhoun V, Hutchison KE. Lifetime Cannabis Use Is Associa