After Marijuana Is Legalized, a New Study Finds, Adolescent Use Declines

Survey data contradict fears that underage cannabis consumption would rise after states allowed recreational use by adults.


Notwithstanding fears that legalizing marijuana for adults would lead to an increase in underage consumption, a new analysis of survey data finds that legalization is associated with a decline in cannabis use by high school students. While it is too early to draw firm conclusions, the results, which were reported online yesterday in JAMA Pediatrics, are reassuring, especially when combined with prior research on medical marijuana laws and state surveys finding no increase in adolescent pot smoking following general legalization.

Based on numbers from the National Youth Risk Behavior Survey for the years 1993 through 2017, Montana State economist D. Mark Anderson and three other researchers found that medical marijuana laws were not associated with increases or decreases in underage use. But when they looked at states that have legalized recreational use, they found that the odds of recent cannabis consumption (i.e., within the previous 30 days) fell by 8 percent, while the odds of frequent consumption (i.e., use on 10 or more of the previous 30 days) fell by 9 percent.

"Consistent with the results of previous researchers," Anderson et al. write, "there was no evidence that the legalization of medical marijuana encourages marijuana use among youth. Moreover, the estimates…showed that marijuana use among youth may actually decline after legalization for recreational purposes." They say "this latter result is consistent with" the results of a 2018 study that looked at adolescent marijuana use in Washington and with "the argument that it is more difficult for teenagers to obtain marijuana as drug dealers are replaced by licensed dispensaries that require proof of age."

While that much is true, it still seems plausible that easier access to marijuana by adults would indirectly facilitate access by minors. Teenagers, after all, have parents, older siblings, and various acquaintances who are 21 or older and could become their suppliers, wittingly or not. But seven years after Colorado and Washington became the first states to legalize recreational marijuana, that phenomenon does not seem common enough to outweigh the impact of an enforceable purchase age, possibly combined with erosion of the "forbidden fruit" effect.

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  1. Eh? teens will be more a-skeered of showing a fake id when pot is legal than buying an illegal substance from an illegal dealer?

    Methinks that is not plausible. More likely they aren’t as interested once it’s legal.

    1. No as cool if mom is doing it.

      1. We don’t need to know why you stopped being interested in anal.

    2. Oh it’s entirely plausible. It’s hard to get a fake ID that can pass muster, and it takes actual balls to produce that fake ID at the point of sale. Buying a bag of weed off your high school buddy is neither difficult nor ballsy. When I was a teenager (late 90s-early 00s), pot was exponentially easier to find than alcohol because you didn’t need to interact with anybody outside your own peer group to get it.

      1. Except Teens have been doing / using fake IDs for alcohol for many decades.

        1. ahhh the 80s. i had seventeen IDs. Gern Blansten from Mississippi was a fave.

          1. Gern! Where ya been man? It’s been ages!

        2. It’s getting harder all the time though, and the consequences for using them are getting harsher.

      2. My experience too. Although I’d think you’d also have to figure in packaging. I was my friends primary alcohol connect but I could only buy enough for a weekend maybe two because storage; while a pound of weed could be more easily stored out of prying eyes. Which made it harder getting if from my source week to week.

        1. Agreed on that point about bulk, yeah.

      3. Look, I saw Super Bad and I know what McLovin’ went through.

  2. Nice job posting at 4:20…

    1. saw too. cute.

  3. Smaller black market means less dealing to kids.

    “easier access to marijuana by adults”

    It was just as easy to get when it was illegal. But since they’re no longer breaking the law, why now risk doing so for someone else?

  4. teenagers don’t want to do things they’re allowed to do.

    1. Except no recreational state has allowed teenagers to legally possess cannabis. It’s still against the law for them, so by your logic that appeal should still exist.

      1. Adults are doing it legally, so it’s no longer cool.

        1. So teens aren’t into alcohol then either? Could have fooled me.

          1. That’s a good question. When I was a teenager, alcohol was everywhere. Nowadays with the helicopter parent thing, plus a parent that’s discovered to be “allowing” alcohol to minors around the house faces real honest to goodness jail time, I rarely hear of the parties of frequency and scale that occurred in my youth.

            I can’t imagine a huge party with 300- yes, literally 300 teenagers paying $5 for a cup at a riverside kegger. The cops would break that up so fast it would make your eyes water.

            1. Yeah – in the ’80s I had friends whose parents would buy us beer because they didn’t want us going out and getting drunk and driving around – i.e. they could keep an eye on us and make sure we didn’t do anything too desperately stupid.

              Hard to imagine parents getting away with that nowadays.

      2. Slyfield said was i was trying to.

        Was in Boston over the weekend and the News25 guy was all happy about how the Coast Guard was “cracking down” on boating under the influence because “while it is legal *in* Mass, it is not legal on the waters”. authority blows.

  5. Teenagers aren’t interested in weed because they’re already addicted to their phones.

  6. “the argument that it is more difficult for teenagers to obtain marijuana as drug dealers are replaced by licensed dispensaries that require proof of age.”

    This seems highly speculative to me. It’s not without logic, but this study just feels off to me. By the way… er, to be sure, I don’t care if there’s a slight or even marked increase of adolescent use after marijuana is legalized, but I just don’t think this is going to be a long-term trend.

  7. Huh. So making something legal reduces the “forbidden fruit” factor and therefore it’s no longer some defiant act of teenage rebellion to smoke pot anymore. It’s almost like the logic of prohibition is self-defeating.

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