When Pollack, now 53, started smoking weed in the early 1990s, it was still illegal across the U.S. By the time medical marijuana became legal on the West Coast during the late ’90s, he was smoking every day. By 2016, he smoked almost constantly, sometimes before his book readings. (He’s the best-selling author of several nonfiction books, including Pothead: My Life as a Marijuana Addict in the Age of Legal Weed.)

By the time Pollack finally quit, in early 2018—though he recovered from his breakdown at the World Series, it scared him into sobriety, he says—weed was legal for recreational use in eight states, and the great wave of legalization was just beginning.

At the time, Pollack’s psychotic breakdown (although it was never officially diagnosed as such) seemed to him like proof that he had a problem with weed, not that weed was itself the problem. But new research suggests that the latter may be true.