NEW YORK (Reuters) - Chances are your teenage son or daughter has heard these lines before -- "Let's party, everybody bounce with me. Sip champagne and burn a little greenery."
It's not a plan for a New Year's Eve party but the lyrics of rapper 50 Cent's "Disco Inferno", which hit No. 3 on the Billboard charts in 2005.
Researchers at the University of Pittsburgh School of Medicine, who studied the lyrics of hundreds of popular songs, found that one in three mention alcohol or drug use.
"We're learning that media affects a lot of different health behaviours," said assistant professor Dr. Brian Primack who headed the study.
"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?"
Primack and his team, who presented their findings at a medical meeting, looked at the top 279 songs on the Billboard charts in 2005. They found that 33 percent made references to alcohol and drug use.
Nearly 80 percent of rap songs mentioned substance use, followed by 37 percent of country music lyrics, 20 percent of R&B/hip-hop and 14 percent of rock songs. Only nine percent of pop songs referred to drug or alcohol use.
The researchers only included songs that clearly referred to using drug and alcohol. They also named the substances which included alcohol, marijuana, cocaine, prescription drugs, inhalants, hallucinogens, and substances of unknown origin.
"If someone says, 'I had one of those pills,' and you don't really know what that was, we call that non specific," Primack explained in an interview.
Rap music contained the most references to alcohol, marijuana and non-specific use, while country music commonly made allusions to alcohol, according to the research presented at the American Public Health Association's Annual Meeting in Washington.
Most lyrical references to substance use were associated with partying, sex, violence and, or humour. The use of drugs and alcohol was motivated by peer pressure, sex, and, or money. Only four songs explicitly had anti-use messages.
At the beginning of the study, the researchers said they found it interesting that Billboard separated rap and hip-hop.
"These really are different markets, with different messages and I think that's something that's really useful to the public health community," said Primack.
He said the next step will be to see if there is a relationship between lyrical content and behaviour.