Declining cigarette use among teens may have helped keep marijuana use from rising in recent years, authors said in a new study.
Adolescents’ beliefs about marijuana risks also remain closely tied to their decision to use the drug, according to the study “Prevalence and Attitudes Regarding Marijuana Use Among Adolescents Over the Past Decade” (Miech R, et al. Pediatrics. Nov. 6, 2017, https://doi.org/10.1542/peds.2017-0982).
Since 2005, adolescent marijuana use has remained relatively steady even though fewer perceive it as harmful. This finding contradicts the notion that teens will be more likely to use the drug if they don’t view it as dangerous.
Researchers tested two hypotheses as to why marijuana use has not increased as expected. First, decreasing use of cigarettes and alcohol may have kept more teens from moving on to marijuana. Second, perceived risk of marijuana no longer strongly influences its use.
To test the two hypotheses, the team from the University of Michigan’s Survey Research Center used the school’s Monitoring the Future surveys from 1991-2016. Adolescents were categorized as having smoked in their lifetime, having drank alcohol but never smoked, or never smoked or drank.
Since 2005, marijuana use increased for each of the three groups individually but not as a whole. Researchers attributed the paradox to the decreasing number of teens in the group that had used cigarettes. Since 2005, the rate of adolescents who have ever smoked a cigarette dropped by 43% among 12th-graders, 55% among 10th-graders and 62% among eighth-graders.
“… as this group grew smaller so too did its disproportionately large contribution to overall marijuana prevalence,” authors wrote.
To see what would have happened if the group of cigarette smokers hadn’t shrunk, they created a formula to project marijuana prevalence over the course of a decade that froze cigarette and alcohol use at 2005 levels.
“These projections indicate that today marijuana use would be at or near the highest levels ever recorded since 1991 in each grade if levels of cigarette and alcohol use had remained at 2005 levels,” authors wrote. “In addition, this projected increase results almost entirely from the decline in cigarette use.”
The team also found there still is a strong relationship between perceived risks and use of marijuana.
“Educational programs and media campaigns that educate youth cohorts about risks of marijuana use — especially heavy use — have been and will continue to be important strategies to prevent youth marijuana use,” authors wrote.
In a related commentary, Nicholas Chadi, M.D., FAAP, and Sharon Levy, M.D., M.P.H., FAAP, past chair of the AAP Committee on Substance Use and Prevention, expressed concerns about marijuana legalization, availability of edible products containing cannabinoids and higher concentrations of tetrahydrocannabinol in cannabis. They, too, called for more education on the risks.
“Dropping perceptions of harm arise from the misconceptions that marijuana is ‘healthy because it is natural’ or ‘safe because it is legal,’” they wrote. “Both of these ideas are false; cannabis is well known to be particularly detrimental to the developing adolescent brain.”
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