Nearly a third of high school students in the United States report smoking marijuana. Despite the mixed messages about the safety of marijuana, it is risky behavior for teens, who are, after all, still developing.

Researchers from Virginia Tech and the University of Washington have demonstrated that a brief, voluntary conversation with an adult led to up to a 20 percent decrease in marijuana use for teenagers who frequently used the drug. The research was published online June 20 in the journal Psychology of Addictive Behaviors, in the article, "Randomized Controlled Trial of Motivational Enhancement Therapy with Nontreatment-Seeking Adolescent Cannabis Users: A Further Test of the Teen Marijuana Check-Up," by Denise D. Walker, Robert S. Stephens, Roger Roffman, Josephine DeMarce, Brian Lozano, Sheri Towe, and Belinda Berg

Walker, research assistant professor of social work and co-director of the University of Washington's Innovative Programs Research Group, said, "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."

But a "non-finger wagging" approach called Teen Marijuana Check-Up could encourage teens to reduce their marijuana use.

"Teen marijuana users have few options for sorting out the disparate information on the risks of smoking marijuana. The programs we are developing and testing will hopefully help fill the gap," said Stephens, chair of psychology at Virginia Tech and director of the addictions lab.

Many teens have concerns about their use of marijuana, "even if they're not sharing them with family or friends," Walker said. If a convenient and easy opportunity to weigh the pros and cons of their drug use is offered that isn't "shaming or blaming," kids will participate in it voluntarily, she said.

The researchers went to high school classrooms and gave short presentations describing myths and facts about marijuana, common reasons why teens smoke it, and its health, and behavior consequences.

The researchers told the students about the study, saying it was intended to give feedback on – not treat – each student's marijuana use. Students could volunteer privately. Of about 7,100 students who heard about the study, 619 volunteered, and 310 met its criterion of smoking marijuana regularly.

The participants, ninth through 12th graders attending Seattle public schools, had two one-on-one meetings with health educators. During the meetings, which lasted 30-60 minutes each over two weeks, the health educators used one of two approaches:

  • Motivational interviewing, in which the health educator and student discussed the student's marijuana use and how it might be interfering with the student's life, goals, and personal values, and the health educator told the student about social norms of how much others use the drug.
  • An educational approach in which a PowerPoint presentation described current marijuana research and health and psychological effects of marijuana use.

Participants in the motivational interviewing group started the study using marijuana 40 out of the previous 60 days. Three months after counseling they had decreased their use 20 percent, to 32 out of 60 days. After a year they still showed a 15 percent decrease, 34 days out of 60.

Participants in the educational treatment group had slower results, reporting an 8 percent decrease from 38 to 35 days out of 60 days three months after the treatment ended. A year later, they reported using marijuana 34 of 60 days, an 11 percent overall drop.

The researchers called the findings "encouraging in that apparently meaningful reductions in cannabis use resulting from the brief meetings were sustained over a relatively lengthy period of time."

Stephens said, "A unique aspect of this research has been our ability to get teens to voluntarily sign up for the programs. Previous research has focused mainly on teens who are coerced into treatment programs by schools, parents, or the legal system, but there are many more users who may profit from talking to someone about their use if we can give them options that are appealing."

Walker said that the low-burden, low-cost program could be disseminated to drug and alcohol counselors in schools. 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," she said.

The study was funded by the National Institute on Drug Abuse. Of the co-authors, Josephine DeMarce of Salem, Va., is a 2006 Ph.D. graduate in psychology from Virginia Tech; Brian Lozano of Charleston, S.C., is a 2008 Ph.D. graduate of psychology from Virginia Tech; Sheri Towe of Martinez, Ga., is a Ph.D. student at Virginia Tech; Roger Roffman is professor of sociology and director of the Innovative Programs Research Group at the University of Washington; and Belinda Berg is a health educator with the School of Social Work at the University of Washington.

Dedicated to its motto, Ut Prosim (That I May Serve), Virginia Tech takes a hands-on, engaging approach to education, preparing scholars to be leaders in their fields and communities. As the commonwealth’s most comprehensive university and its leading research institution, Virginia Tech offers 240 undergraduate and graduate degree programs to more than 31,000 students and manages a research portfolio of $513 million. The university fulfills its land-grant mission of transforming knowledge to practice through technological leadership and by fueling economic growth and job creation locally, regionally, and across Virginia.

University of Washington PR contact Molly McElroy contributed to this news release. Email her or call 206-543-2580.


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