Researchers found that a rise in use of marijuana among US teens over the past 20 years is not linked to the legalization of medical marijuana in several states.
Federal officials have argued that recent increases in use of marijuana among teens might be a result of better access to the drug in states where it is legal. However, a new study found that there is no evidence that legalization of marijuana for medical purposes increases teen drug use.
Researchers compared surveys of marijuana use by teens conducted annually by the Centers for Disease Control and Prevention (CDC). The data comes from a period when 16 states legalized medical marijuana and allowed the researchers to estimate the effect of legalization on outcomes such as marijuana use in the past month, frequent marijuana use and use of the drug on school property. Results of the study show that the probability a high schooler had used marijuana in the last 30 days was no more than 0.8 percent higher in legal states compared to states that had not approved medical marijuana.
“Our results are not consistent with the hypothesis that the legalization of medical marijuana caused an increase in the use of marijuana among high school students,” D. Mark Anderson of Montana State University, Daniel Rees of the University of Colorado and Benjamin Hasen of the University of Oregon wrote in their report.
Opponents of legalization of the drug have expressed concern on its impact on teens. A previous study, published in the Annals of Epidemiology in 2011, found that use among adolescents had risen in states where medical marijuana was legal, but concluded that more research was needed to determine a causal relationship. Further, the study found that between 2002 and 2008, use among teens was highest in states where the drug was legal; however use was already higher in those states before it was legalized.
Last updated: 7/29/14; 3:30pm EST