A newly published study points to recreational legalization of marijuana as a potential cause of lower usage rates among teens in those areas. Using data from over two dozen years, the paper from a team at Montana State University looked at teens from before and after marijuana was legalized and how their overall habits changed with the laws and time. The data also stretched from lengths of time when only medical marijuana was legalized and how recreational legalization is actually affecting today’s teenagers.

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What The Study Found

Looking at data collected by the Centers for Disease Control (CDC), a group of researchers from Montana State University found that teens living in areas that have undergone legalization are less likely to use marijuana. By looking at the more than 1.4 million teenagers habits from the CDC’s Prevention for its Youth Risk Behavior survey from 1993 to 2017, researchers got a larger look at how cannabis prohibition, medical legalization and recreational legalization truly affected young adults. The annual survey provided self-reported results that looked at teens before and after marijuana laws.

CDC study Source: Centers for Disease Control and Prevention
Overall, teenagers are ten percent less likely to consume marijuana in states where cannabis is legal.  Eleven states have legalized marijuana for recreational use, with Illinois becoming the most recent in June. Colorado and Washington were the first to legalize the plant for recreational use in 2014. Marijuana is legal in 33 states for medical purposes.

Researchers found a nine percent drop in the number of teens who said they had used it at least 10 times in the last 30 days and an eight percent drop in the number of high schoolers who said they used marijuana in the last 30 days. The authors of the study suggested in the paper that the number of added hurdles in getting legal marijuana, such as having to be 21 years or older, make it harder for teens to get a hold of it.

The study, which was published by the JAMA Network, was lead by Mark Anderson with  Benjamin Hansen, Daniel Rees and Joseph Sabia.

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What Does The Study Mean?

Minneapolis, Minnesota, USA - August 7, 2016: Volunteers for Dennis Schuller campaigning in Northeast Minneapolis during the Open Streets Northeast event on a platform for "Legal Marijuana Now." iStock / Wikileaf
While the study does fly in the face of one of the most common arguments to not legalize marijuana, it isn’t the end of the road. The study doesn’t altogether prove that legalization will not cause an epidemic of stoner teenagers, but it does lean toward the opposite.

This falls in line with some other prominent studies that have come out over the past year with roughly the same conclusion: that legalization of marijuana doesn’t increase use in young people. However, while that scenario would need full legalization nationwide to truly test, it is a good sign going forward. A similar study published by the American Journal of Drug and Alcohol Abuse earlier this year looked at teen use in states with legal medical marijuana.  With over 30 states to look at, the researchers looked at over 860,000 teens aged 14 to 18 between 1999 and 2015 in 45 states and found that teens in states with some form of marijuana didn’t use as much.

The lead author of the paper, Rebekah Levine Coley, a psychology researcher at Boston College, told Reuters that “Adjusting for numerous other substance use policies, medical marijuana laws were associated with small declines in current marijuana use among adolescents, with larger declines in some subgroups, such as males and African American and Hispanic adolescents.”

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Unlike the Montana study, this one looked more at factors such as race and how marijuana use changes for those groups.

The Race Factor

Police frisking a black teen San Francisco, California, USA - May 19, 2015: SFPD officers patdown black american man in San Francisco. Overall, Black Americans are arrested at 2.6 times the per-capita rate of all other Americans. (iStock / chameleonseye)
The study found that not only did some states have widely varying differences in use among them, including a nearly 20 percent difference of teens who use in Utah with 8.6 percent and Vermont with 28 percent.

Using a statistical model and method to allow the researchers to account for state differences, they were able to determine the overall likelihood that teens would use marijuana. Coley and her team found that the chance that a teen would use marijuana is 18.9 percent in states with laws permitting medical marijuana and 20 percent in other states.

This one-point-one percent difference may not seem like much, but when applied to arguments and concerns about what a country with weed legally available in 50 states means, it is noteworthy. The percentage difference isn’t one across the board, however, with black and Hispanic use being double or triple that. 

Looking at the data by race, the researchers found that the probability of marijuana use for by black youth was 3.9 percentage points lower in states with medical marijuana laws, while it was 2.7 percentage points lower for Hispanic youth.

Overall, each year the states had some form of legalization, the rates continued to decrease. The study also pointed out that marijuana laws had no impact on whether or not a teen would become a heavy or daily smoker.

Going Forward

The world isn’t going to be done believing that marijuana is a horrible thing overnight, but studies like these do show the larger picture more clearly than we can see it on our own sometimes.

Marijuana use in teens will undoubtedly change over time as states begin to legalize more and the industry grows, however, adult-use will also change. Many legal states have some form of drug education programs that are mandated when the laws are passed, meaning that overall knowledge on what marijuana is and does is likely higher than in other states.

When it comes to arguments that marijuana will corrupt your kids, well, the results may take a couple of decades.