Recreational marijuana legalization had no impact on how many Colorado teens use pot or on whether they think it is dangerous, but that could be because years of medical marijuana sales already had brought about changes in those measures, according to a new study.
The study, posted on the website of the journal JAMA Pediatrics on Tuesday, looked at national survey data and concluded that the percent of teens from Colorado who said they had used marijuana in the past month was statistically unchanged between the pre-legalization years of 2010 to 2012 and the post-legalization years of 2013 to 2015.
Similarly, the study found that a shift in Colorado teens’ attitudes toward marijuana’s risks — kids are less likely today to say they think using marijuana can be harmful to health — was not statistically different from the national trend.
That contrasts with Washington — which, along with Colorado, legalized recreational marijuana use and sales in 2012. The study found kids in eighth and 10th grades in that state are more likely to use marijuana since legalization and have shifted even more than the national trend toward thinking marijuana use doesn’t pose a great or moderate health risk.
“Our study didn’t particularly tell us why” the two states differed, said Magdalena Cerdá, a researcher at the University of California-Davis Violence Prevention Research Program and the lead author of the study.