How bad was the NFL's drug problem in the 70's and 80's

The book and movie North Dallas Forty did a lot of telling like it was. I know people that used to hang out with some of the Saints in the 70's and told stories about how Lindsay Scott & Chuck Muncie (2 1st round picks with star potential) ruined their careers. Of course, it wasn't just the Saints. The league is a lot cleaner today.