A University of Pittsburgh Medical School study is suggesting a correlation between the content of music lyrics and the potentially dangerous behavior of young people. Researchers examined the top 279 songs on Billboard charts during 2005. They found that 33% contained references to drugs or drug use. Over 80% of rap songs in the study made some reference to drug usage. On the other end of the spectrum, only 14% of rock songs made drug references. Researchers became interested in the lyrical-content of popular music when they considered the battle against cigarettes in movies and television. Assistant Professor Brian Primack explains: "Tobacco in movies, for example, is now known to lead to smoking. We started realizing adolescents are exposed to two and a half hours a day of music. What's in the music?"ÂÂ Primack also added that the next step would be establishing a clear correlation between lyrical content and behavior. [Reuters]