New insights into factors affecting adolescent marijuana use

What factors are associated with a higher or lower risk of marijuana use among adolescents? There are some important differences for boys versus girls, according to a study in the March Journal of Addiction Medicine, the official journal of the American Society of Addiction Medicine. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health.

For both sexes, participating in extracurricular activities is associated with a lower rate of marijuana use, according to the study from Yale University School of Medicine, led by Ty S. Schepis, Ph.D. "These findings may facilitate the development of gender-informed prevention and early intervention programs for adolescent marijuana use," Dr. Schepis and colleagues write.

New Insights into Factors Affecting Adolescent Marijuana Use
The researchers analyzed data from a statewide survey of high-risk behaviors among Connecticut high school students, performed in 2008. In addition to assessing reported rates of marijuana use, the researchers looked at gender differences in the factors related to lifetime or current use. The survey included data on approximately 4,500 teens.

Overall, 40 percent of the adolescents surveyed said they had ever used marijuana (lifetime use), while 24.5 percent had used it within the last 30 days. Both figures were higher for boys: 42 versus 39 percent for lifetime use and 27 versus 22 percent for past-month use. Younger students and those with better grades were less likely to report using marijuana.

Teens who engaged in other high-risk behaviors—especially using cigarettes, alcohol, and other substances—were more likely to use marijuana. Other risky behaviors were also linked to marijuana use, including carrying a weapon, fighting, any form of self-harm, and depressed mood.

There were some significant interactions between gender and race/ethnicity, including higher rates of marijuana use among African American and Hispanic/Latino boys. White girls were more likely to use marijuana, while use was less likely for girls of African/American or Asian/"other" descent. Preliminary evidence suggested that, once girls started using marijuana, they made a faster transition to regular marijuana use compared to boys.

The factor most strongly associated with lower rate of marijuana use was participating in extracurricular activities. Girls with extracurricular participation were nearly one-half less likely to use marijuana, while boys were more than one-fourth less likely.

Marijuana use by teens is a "significant public health problem" linked to increased rates of psychosocial problems, including anxiety and depression symptoms and other forms of substance abuse. Information on how teen marijuana use is affected by gender, ethnicity, and other factors could help in designing effective prevention or early-intervention programs.

The new findings will promote this goal by providing a "clear profile of adolescent marijuana users," Dr. Schepis and co-authors believe. "Risk behaviors, with other substance use in particular, seem to be associated with the greatest elevations in odds of marijuana use across genders," they write. "Extracurricular activity participation seems to be the most robust factor associated with decreased odds of marijuana use, in both males in females."