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As Cannabis Legalization Has Expanded in U.S., Marijuana Use by Teens Has Fallen

Cannabis use among adolescents has fallen by 17 percent between 2002 and 2014, during which 19 states passed marijuana measures.

According to findings in a new study published in the Journal of Clinical Psychiatry, cannabis use by young people has decreased as marijuana legalization has expanded throughout the United States. Federal investigators from the U.S. National Institute on Drug Abuse and the Substance Abuse Mental Health Services Administration examined the rates of cannabis use among adolescents ages of 12 to 17 between the years 2002 and 2014.

“In the United States, compared to 2002, even after adjusting for covariates, cannabis use decreased among youth during 2005-2014, and cannabis use disorder declined among youth cannabis users during 2013-2014,” the investigators concluded.

The prevalence of past-year cannabis use fell by 17 percent (from 15.8 percent in 2002 to 13.1 percent in 2014) during the time period. The prevalence of problematic use by adolescents fell by 25 percent (from 27 percent in 2002 to 20.4 percent in 2014), with the downward trend beginning in 2011. The analysis also indicated an association between declines in teen cannabis use with a drop in tobacco use, which the investigators suggest emphasizes “the importance of tobacco use control and prevention among youth.”

A common argument among opponents to marijuana legalization is the potential negative impact on use by teens. However, time and time and time again, studies have found that legalization has had zero negative impact on the prevalence of adolescent marijuana use.

Between 2002 and 2014, four U.S. states – Colorado, Oregon, Washington, and Alaska – legalized recreational marijuana, and 15 U.S. states — Arizona, Connecticut, Delaware, Illinois, Maryland, Massachusetts, Michigan, Minnesota, Montana, New Hampshire, New Jersey, New Mexico, New York, Rhode Island, and Vermont — passed laws allowing marijuana for medical purposes. The expansion of legalization has clearly not encouraged use by teens.

Earlier this year, a study from the Washington Department of Health found that cannabis use by adolescents in the state of Washington has remained virtually flat after marijuana was legalized in 2012 and dispensaries began selling adult use cannabis in 2014.

Like the findings in earlier studies, this most recent analysis is encouraging to advocates, as market analysts have predicted that despite efforts from officials in the Trump administration to interfere with states passing and implementing cannabis measures, legalization could expand to all 50 U.S. states in just a few years.

For this latest study, the investigators used data from 288,300 adolescents who participated in the 2002-2014 National Survey on Drug Use and Health. They applied descriptive analyses and bivariable and multivariable logistic regressions to examine the changing trends in cannabis use.

You can access the entire study, “Cannabis use and cannabis use disorders in the United States, 2002-2014,” via The Journal of Clinical Psychiatry.

As of today, eight states and Washington D.C. have legalized recreational cannabis and 29 states plus Washington D.C. have legalized medical marijuana. Learn more about current cannabis laws in the U.S. by visiting our education page. Keep up with the latest developments in the cannabis industry through our news feed.