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Legalization of marijuana and youths’ attitudes toward its use

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What the evidence says

Colorado legalized marijuana for medical use in 2000, and for adult recreational use in 2014. A 2012 study of adolescents receiving substance abuse treatment in Colorado found diversion of medical marijuana to these adolescents was common.6 This study also reported that compared with those who did not use medical marijuana, adolescents who used medical marijuana had an earlier age of regular marijuana use, more marijuana use disorder symptoms, and more symptoms of conduct disorder.6 However, data from the US Substance Abuse and Mental Health Services Administration7 and from the Colorado Department of Public Health & Environment8 suggest that marijuana use among adolescents has not increased since legalization in Colorado.

In 2012, voters in Washington state legalized marijuana for recreational use. In 2013, Moreno et al9 interviewed college students in Washington, where marijuana had just been legalized, and Wisconsin, where it had not. In both states, most participants indicated that legalization would not change their attitude towards use. A small proportion of students felt that legalization would signify an endorsement of marijuana, and they were likely to perceive it as safe to use.

In an analysis of data on more than 250,000 students in 8th, 10th, and 12th grade, Cerdá et al10 found that after legalization in Washington, the perceived harmfulness of marijuana decreased and marijuana use increased among 8th and 10th graders in Washington; however, there were no significant differences noted among adolescents in Colorado.

In 2010, voters in California passed legislation to decriminalize marijuana. In an analysis of data from 8th, 10th, and 12th graders in California, Miech et al11 found a positive correlation between decriminalization and increases in youth future marijuana use. They also found that compared with their peers in other states, 12thgraders in California were more likely to have used marijuana in the last 30 days, less likely to perceive marijuana use as a health risk, and less likely to disapprove of its use.11

Although some studies have suggested that legalization of marijuana might increase use among adolescents, limitations of these studies include that they relied on self-reported use by adolescents, and they did not evaluate adolescent populations outside of school settings.

Continue to: Addressing adolescents' marijuana use

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