Yet Another Study Debunks the Myth that Marijuana Legalization Encourages Teen Use

The expansion of marijuana legalization in the U.S. has had virtually no impact on the rate of use among teens.

Evidence continues to reveal that legalizing marijuana has no adverse impact on the rate of cannabis use among teens. Most recently, researchers at the Columbia University’s Mailman School of Public Health found no link between legalization and use among adolescents after analyzing data from 11 separate studies dating back to 1991. Their findings were published in the latest issue of the journal Addiction.

“For now, there appears to be no basis for the argument that legalizing medical marijuana has increased teens’ use of the drug,” said Deborah Hasin, PhD, professor of Epidemiology and the study’s lead author. “However, we may find that the situation changes as commercialized markets for medical marijuana develop and expand, and as states legalize recreational marijuana use.”

Legalized medical marijuana first came to the United States by way of California in 1996. Since then, 29 states have passed laws legalizing marijuana use for medical purposes. Opponents of cannabis legalization traditionally argue that loosening policies will stimulate greater use among adolescents.

Researchers, however, have debunked that myth time, and time, and time, and time, and time again. A recent federal report found that despite marijuana being legal in some capacity in more than half of the nation, teen cannabis use is at a 22-year low.

“Several years ago, before the group of papers we [analyzed] started to be published, people thought that medical marijuana laws would increase teen marijuana use by ‘sending the message’ to teens that marijuana was safe and acceptable to use,” said Hasin.

The study by Hasin and her colleagues used the findings of 11 studies from 1991 to 2014 that had investigated the rate of teen marijuana use. They then compared those trends in the past month and before and after marijuana laws had been enacted. Teens’ usage of marijuana did not change after the medical marijuana laws were passed.

What About Adults?

The researchers did note that their study did not look at the impact on medical marijuana legalization on the rate of use by adults. Hasin added that she believes it’s an important topic that needs to be investigated considering more states will likely legalize medical and recreational marijuana in the short future.

“Although we found no significant effect on adolescent marijuana use, existing evidence suggests that adult recreational use may increase after medical marijuana laws are passed,” said Hasin.

“The $8 billion cannabis industry anticipates tripling by 2025. Obtaining a solid evidence base about harmful as well as beneficial effects of medical and recreational marijuana laws on adults is crucial given the intense economic pressures to expand cannabis markets.”

In addition to the 29 states that have legalized medical marijuana, nine have legalized recreational marijuana. Oklahoma voters will get to decide whether to legalize medical marijuana during the primary election June, and efforts to legalize medical marijuana are underway in Missouri and Utah. In Michigan, a campaign group is currently collecting signatures for a ballot measure that proposes legalizing recreational marijuana.

Learn more about cannabis industry trends to keep an eye on this year HERE.

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Keep Up with Cannabis Research

You can get access to the entire new study, “Medical marijuana laws and adolescent marijuana use in the United States: A systematic review and meta-analysis,” through Addiction.

Keep up with the latest cannabis-related studies by regularly visiting our news page.