As 2012 comes to a close, there are a few drug- and alcohol-related stories I’d like to forget. But forgetting isn’t always the best way to cope with the unpleasant repercussions of US drug policy. For several generations, social psychologist Lloyd Johnston’s statistics have quantified the adage that those who cannot remember the past are doomed to experiment with bath salts (more on that in a minute).
In 1975, Johnston and his colleagues at University of Michigan began conducting the nationwide survey, Monitoring the Future. By pairing these results with the National Household Survey on Drug Abuse (initiated in 1971), we have been able to get a fairly accurate annual look at drug use prevalence for almost four decades. Both surveys were inspired, in part, by the increase in youthful experimentation with psychoactive substances (especially marijuana) in the 1970s. While substance use trends come and go, academic interest in youthful drug use has remained stable.

In examining trends in drug use over the course of several decades, Johnston and his colleagues noticed a pattern: