Study author Denise Herd of the University of California, Berkeley, and colleagues sampled 341 lyrics from the most popular songs in rap between 1979 and 1997 and categorized each song in terms of its drug mentions, behaviors and contexts, as well as its attitude towards drug use and consequences. Rap genres were also categorized, and drug-type mentions were coded and analyzed.

The study, published in Addiction Research & Theory, found songs with references to drugs increased six-fold over from 1979 to 1997. Songs exhibiting positive attitudes toward drugs and the consequences of drug use also rose exponentially, drug types mentioned changed significantly and references of using drugs to signify glamor, wealth and sociability increased as well.

Of the 38 most popular songs from 1979 to 1984, or 11 percent contained drug references, but by the late 1980s that number had increased to 19 percent and by 1993, 69 percent of rap songs mentioned drug use, Herd said.