MDMA and cannabis are both quite popular and talked about openly but I think that's more a general reflection of the culture in places like NYC and the Bay Area, where I have personal experience.
Good luck with the book by the way. One word of warning: please try very hard to avoid falling into a simplistic narrative that will contribute to drug prohibition. Criminalization of drugs has, IMO, ruined far more lives than drugs themselves. A former Columbia colleague, Carl Hart, professor in the psych department, has written a lot on this and might be worthwhile as an interview subject for your book. Personally I think he sometimes pushes too far in the opposite direction, but he is nevertheless an important public voice speaking up against decades of scaremongering.
Postdocs and junior faculty are generally worked to the bone for little money. Postdocs need to crank out papers that benefit the lab, but also advance their own career prospects; faculty need to do the same, as well as write grant applications, serve on prestigious committees in order to look good for tenure review, etc.
There aren't enough hours in the day.