Teens' Daily Marijuana Use Is On the Rise


WASHINGTON — The 2010 Monitoring the Future results showing a significant increase in marijuana use among American adolescents over the last year confirm earlier surveys and are profoundly disturbing, addiction medicine experts say.

“The new data stand as one more sign that those who promote 'medical marijuana' and the legalization of marijuana by emphasizing the drug's safety are reducing the perception of risk of use among youth,” Dr. Robert L. DuPont, the first director of the National Institute on Drug Abuse (NIDA), said in an interview. “This is translated directly into significantly increased levels of use.”

Dr. Mark S. Gold said these perceptions of safety are rooted in lack of awareness about strong data to the contrary.

“Unfortunately, as in the past, drugs of abuse are widely viewed as safe until proven dangerous,” said Dr. Gold, Donald R. Dizney Eminent Scholar and distinguished professor at the McKnight Brain Institute at the University of Florida, Gainesville. “Meanwhile, medications – even those that are potentially life-saving – are properly viewed as dangerous until proven safe.”

The 2010 Monitoring the Future results, presented at a Dec. 14 press conference, showed that the percentage of American teenagers reporting daily marijuana use increased significantly from 2009 to 2010. The percentage of 8th, 10th, and 12th graders reporting daily marijuana use increased from 1.0% to 1.2%, 2.8% to 3.3%, and 5.2% to 6.1%, respectively. In a statement, Lloyd D. Johnston, Ph.D., principal investigator of the study, called the increase in daily marijuana use among students in all three grades “perhaps the most troublesome” aspect of this upward shift.

The study defines daily or near-daily use as use on 20 or more occasions in the prior 30 days. About 1 in 16 12th graders use marijuana on a daily or near-daily basis, according to the study.

However, past-year and past-month reported use increased among 8th graders only.

Attitudes about marijuana use are clearly changing among American adolescents – for the worse. The 2010 results show a decline in the percentage of 8th graders who disapprove of marijuana use, and declines in the percentage of 10th and 12th graders who said they perceived a “great risk” of harm associated with smoking marijuana regularly.

These perceptions exist despite the wealth of evidence on harmful impact of adolescent cannabis use. Dr. Gold said marijuana-related learning problems and accidents are common now among high school and college students.

In addition, he pointed to the inherent dangers of inhaling drug vapors. Nonmedical drug use can cause long-term changes in the brain. A study published last year showed that cannabis use is a significant risk factor in the etiology of psychosis among adolescents (J. Psychosom. Res. 2010;69:533-9).

The Monitoring the Future survey also showed that other drugs are gaining popularity among American adolescents.

For example, Ecstasy use is on the rise after almost a decade of decline, Dr. Johnston, a research scientist at the University of Michigan, said at the press conference.

In 2010, 2.4% of 8th graders and 4.7% of 10th graders reported past-year Ecstasy use, up from 1.3% and 3.7%, respectively, in the 2009 survey.

The decline in cigarette smoking appears to have stalled across all three grade levels, and nonmedical use of many prescription drugs, including OxyContin and Adderall, remained similar to last year's levels among 12th graders.

On the positive side, past-year reports of alcohol consumption among 12th graders declined, from 43.5% to 41.2%, and binge drinking dropped from 25.2% to 23.2%, Dr. Johnston said.

Also, nonmedical use of the prescription painkiller Vicodin decreased among 12th graders, he noted.

The changes in drug, cigarette, and alcohol use also reflect changes in teens' perceptions of the risks associated with these products, Dr. Nora D. Volkow, director of NIDA, said at the press conference.

Dr. DuPont said these data showing an increase in youth drug use is “not so much a measure of youthful irresponsibility as it is a reflection of the failure of adult stewardship for youth.

“That stewardship should include ensuring that American youth grow up not using illegal drugs, which for them includes alcohol and tobacco,” said Dr. DuPont, president of the Institute for Behavior and Health Inc., a nonprofit drug-policy research organization in Rockville, Md.

“This new data make that point and provide a much-needed call to action for parents, teachers, [physicians], and all adults who care for kids to get involved and stop all of their illegal drug use,” Dr. DuPont said.

Physicians are in a unique position to help teenagers – and their parents – understand the dangers of drugs, alcohol, and cigarette use, Dr. Johnston said.

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