Teens who listen to music that talks about marijuana are more likely to use the drug than those who don't, according to a study from the University of Pittsburgh.

Dr. Brian Primack said the result was based on surveys of nearly 1,000 ninth-graders.

Those who listened to music with the most references to pot were twice as likely to have tried it than those who listen to cleaner songs.

He said, however, that there was no link between the music and other risky behaviors such as drinking alcohol.

"This suggests that there is a real link between the marijuana lyrics and marijuana use," Primack said.

In the study, teens averaged listening to about 22 hours of music a week. They heard about 40 references to marijuana each day.

Twelve percent of the students said they use marijuana, and 32 percent said they had tried it.

Though the study tried to factor out influences such as age, race and gender, it could not be said for sure that the music caused drug use.

"Although it may be that heavy exposure to music about marijuana causes marijuana smoking, it may also be that those who smoke marijuana seek out music with lyrics related to marijuana," Primack said. "In either case, these results may help us develop more effective programs on drug education."

The study was published in the journal Addiction.