WEDNESDAY, July 6 (HealthDay News) -- Brief, voluntary and non-judgmental conversations with teens about marijuana use may significantly reduce their use of the drug, according to a new study.

Researchers also found that a motivational approach to these discussions about marijuana was more effective than merely educating high school students on the health effects of the drug.

Marijuana is a common drug choice for teens around the world. In the United States alone, nearly one-third of high school students report smoking pot. Many of them do so because they don't realize the health consequences of using the drug, according to researchers at the University of Washington.

"It's not a risk-free drug," Denise Walker, co-director of the University of Washington's Innovative Programs Research Group, said in a university news release. "Lots of people who use it do so without problems. But there are others who use it regularly -- almost daily -- and want to stop but aren't sure how."

Complicating matters, the risks associated with marijuana use are greater for teenagers than adults, noted Walker. "Adolescence is a big developmental period for learning adult roles. Smoking marijuana regularly can impede development and school performance, and it sets kids up for other risky behaviors," she added.

The researchers found, however, that marijuana use among teens could be reduced significantly through direct and intimate talks. In conducting the study, published online in a recent issue of Psychology of Addictive Behaviors, researchers met with 310 high school students to provide them with feedback -- not treatment -- on their regular marijuana use.

Each student had two, one-on-one meetings with health educators that lasted up to an hour and used either a motivational or an educational approach.

The students who attended the motivational meeting discussed how marijuana could be interfering with their goals, life and values. Those who received the educational approach saw a presentation outlining the health and psychological effects of marijuana use.

The investigators found that the teens who attended the motivational meetings cut back on their marijuana use by 20 percent within three months. One year after their meetings, they still had a 15 percent drop in their use of the drug.

Although they had less dramatic results, participants in the educational treatment group reported an 8 percent decline in marijuana use three months after their meetings. A year later, they maintained an 11 percent overall drop.

The study authors added that this low-cost and low-burden approach to curbing marijuana use among teens should be distributed to high school drug and alcohol counselors. The program "is supposed to attract people who aren't ready for a full treatment, but are interested in having a conversation with a professional trained to discuss concerns with substance use," Walker said.

More information

The U.S. National Institute on Drug Abuse provides detailed information on marijuana abuse.