Is Legal Marijuana Changing Teen Habits? Study Shows Impact Is "Unclear"

While America’s Surgeon General issued a warning about the “unprecedented” teen vaping epidemic this week, another statistic from the annual, nationwide Monitoring the Future Survey flew under the radar. Amid a wave of marijuana legalization across the United States, teen marijuana use showed a very interesting pattern: It barely changed at all.

In the eyes of marijuana legalization advocates, this is big news. Across America, ten states have now legalized recreational weed, and medical marijuana is legal in 33. Meanwhile, the survey shows that roughly 14.5 percent of teens reported smoking weed in the past 30 days of taking the survey in 2017, and 14.6 reported that same behavior in 2018. And since 2006, the percentage of 8th, 10th, and 12th graders that have reported smoking weed has hovered consistently between 12 and 15 percent.

The marijuana advocacy group NORML, along with a handful of others, frame these patterns are evidence that legalization won’t actually cause more teens to use cannabis, as many critics have argued.

Jason Hockenberry, Ph.D., an Emory University health economist with a forthcoming study on adolescent marijuana use, agrees that the new results could be an early sign that legalization won’t affect teens for the worse. He cautions,k however, that it doesn’t constitute definitive evidence for those who harbor doubt.

“It shows there has not been a short-term effect,” he tells Inverse. “It is also possible that these laws may have a delayed effect. Our forthcoming work shows that attitudes toward the health risks of cannabis do shift as cannabis laws become more liberal, including attitudes among teens.”

Concerns about teen smoking have been one sticking point in of the argument against marijuana legalization in the United States and beyond. Despite some therapeutic effects in adults, there is some evidence that it’s not so great for teens. In teens, it’s been shown to affect working memory more drastically than alcohol or lead to emotional deficits. Other studies, however, suggest these concerns are overblown. The fact is that we still don’t know how safe it is for teens to use marijuana.

The American Academy of Child and Adolescent Psychiatry policy statement expresses concerns that legalization will make it easier for teens to get high and expose them to potentially harmful effects down the road, though it notes that legalization may have other beneficial effects on society.

Critics’ concerns that legalization might change how teens perceive the health risks of weed are warranted. There’s already plenty of evidence that teens have been changing their minds about that for a long time, as were captured in the Monitoring the Future survey: This year, 26.7 percent of high school seniors said that smoking weed regularly was a great health risk, down 2.2 percent from last year. Similarly, in 2006, 57.9 percent of teens thought that regularly smoking weed was bad for them. In 2012, a year in which marijuana was legalized in two states, that number had dropped to 44.1 percent.

But as for whether changing attitudes will lead to increased use. Hockenberry adds that there’s still not a consensus.

“What may happen in that age bracket is unclear,” adds Hockenberry. “What is currently happening is young people’s health risk perceptions. What changes in perceptions will or won’t do to use is unclear at this point, though research on other substances in previous generations ties lower perceived health risk to more initiation of different substances (alcohol, tobacco, etc), and that may be the case for cannabis.”

The latest survey results probably aren’t the silver bullet legalization advocates have been looking for, but they may be in a few years, as legalization laws have time to take effect. For now, they’ll have to keep an eye on Canada, where the legal marijuana story is unfolding already.