Science & tech

Cannabis Legalization and Teenage Use: What Do Studies Tell Us?

Published on October 7, 2014 · Last updated July 28, 2020

Teenage cannabis use is a touchy subject, especially as cannabis continues to become more legally accessible medically and recreationally. In areas where cannabis is legal for recreational use, laws are in place (as they should be) to prevent use by anyone other than adults. However, concerned parents fear that with legalization will come an increased use in cannabis among minors, leading them to think that their otherwise upstanding and ambitious kids will succumb to the sweet siren song of a sativa strain or the icky clutches of an indica. How valid are these fears — will widespread legalization lead to the corruption of today's youth? 

Actually, recent studies on cannabis use among teenagers may surprise you. First, the concerns: a growing number of studies are showing that regular cannabis use can change the structure of a developing teenage brain, especially in memory and problem solving areas. As a result, cognition and academic performance can be adversely affected, and heavy cannabis users can see a drop in as many as eight IQ points as they transition to adulthood. Furthermore, teenagers who consume cannabis on a daily basis are more than 60% likely to not complete high school vs. those who don't consume. They're also 60% less likely to graduate college and seven times more likely to attempt suicide at some point. Based on all of these studies, we should all be terrified about the idea of cannabis ending up in the hands of minors, right? The findings are terrifying enough that you'd think even looking at a cannabis bud when you're under the age of 18 would cause you to go insane.

These studies, as serious as they are, have some caveats. Regarding the lower IQ findings, the test subjects who consumed the most cannabis already had lower IQs to begin with. And regarding the statistic where heavy teenage users are 60% less likely to graduate high school and are several times more likely to attempt suicide, we run into a causation/correlation problem. Dr. Gregory Tau, a psychiatrist and drug abuse researcher at Columbia University, puts it aptly: 

"It's very possible that there's something very different to begin with among teenagers who tend to get into trouble with marijuana or who become heavy users," Tau says. "They could have subtle emotional differences, perhaps some cognitive functioning differences. It may be hard for them to 'fit in' with a peer group that's more achievement-oriented."

These teenagers who are being adversely affected by heavy cannabis use could have a number of factors contributing to the situation — perhaps they have much less adult or parental supervision, or they come from a difficult home life, or they're struggling with undiagnosed or unidentified personal or mental health issues that would benefit from therapy or a medical diagnosis. With these variables, it's difficult to say whether cannabis caused these teenagers to have a higher risk of dropping out of school, or whether they were already troubled teens who happened to start heavily using cannabis. Yes, these studies have highlighted some concerns, but they've also raised more questions and require additional research to help eliminate as many variables as possible; only then can we make better conclusions about cannabis' adverse qualities. 

Now onto the positives: since Colorado has legalized recreational cannabis, teenage cannabis use has actually dropped, with use in the past month dropping from 22% in 2011 to 20% in 2013 and use at any period declining from 45% to 39%. In fact, so far it appears that as a whole, legalization of recreational cannabis has not resulted in an increase in teenage cannabis use. So what's the reason for the decline?

Some speculations include the fact that some of the tax revenue being collected in recreational markets is being put towards drug education and prevention, so more education programs are being targeted towards youths. These programs are likely taking a less sensationalized approach than the DARE-tastic programs of yesteryear, presenting teenagers with realistic information that encourages them to make smart choices and wait until they're adults (unless, of course, they have a medical condition that's being treated with medical marijuana). Perhaps, too, as the conversation about cannabis continues to gain traction, more parents are forced to have an honest, transparent discussion with their children about drug use. Or maybe teenagers are going the hipster route, eschewing cannabis for being too "mainstream" now that it's being legalized and permeating our culture. 

Whatever the reason, it's a positive sign that legalizing cannabis isn't the end of the world as we know it for the bright minds of tomorrow. Of course, that doesn't mean that parents shouldn't just sit back with their hands in their pockets and expect their kids will naturally make the right decision about cannabis. The study about regular cannabis use changing the structure of a developing brain supports the idea that cannabis use is primarily reserved for responsible adults. The brain keeps developing as far into the age of 24, so cannabis abuse may indeed run the risk of adversely affecting a young consumer's cognitive and developmental growth potential.

Additionally, a recent TIME magazine issue found that one of the few commonalities among households from widely different income brackets is the rate in which individuals have tried cannabis by the age of 16. The breakdown is as follows:

  • Households earning at least $200k per year: 31%
  • Households earning between $100k – $199k per year: 33%
  • Households earning between $60k – $99k per year: 34%
  • Households earning between $30k – $59k per year: 37%
  • Households earning less than $30k per year: 34%

That figure is very similar across the board. Compare that to other statistics such as sex by the age of 16 (in descending order of household income: 32%, 41%, 46%, 54%, and 61%), college education (83%, 74%, 56%, 35%, and 20%), and being charged with an adult crime by the age of 24 (11%, 12%, 15%, 18%, 21%) and you'll notice that the mere act of trying cannabis as a teenager transcends demographics. That doesn't mean I'm saying, "Hey, everyone tries cannabis when they're a teenager so what's the big deal?" — rather, I'm pointing out a simple fact and encouraging parents to communicate with their children knowing that their teenage son or daughter one day finding themselves in a situation where they can try cannabis is a real possibility. 

Cannabis isn't going away any time soon, which means it's more important than ever to educate everyone on cannabis basics, responsible use, and why consumption should be limited to mature, capable adults or those with a legitimate medical need. With two states having legalized recreationally and dozens more legalizing medical cannabis, we've shown an impressive amount of maturity and responsibility thus far. Let's keep this trend going and continue proving to legalization opponents that information, continued research, and communication are the keys to acceptance, trust, and reform.

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Rebecca Kelley
Rebecca Kelley
Rebecca is the Content Director at Leafly, where she oversees Leafly News production and other content projects.
View Rebecca Kelley's articles
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