Feb. 15 (UPI) -- Teens living in states in which marijuana has been legalized for adults are more likely to use the drug than their peers in states in which it remains illegal, a report published Monday by the Journal of Studies on Alcohol and Drugs found.
After California legalized adult recreational marijuana use in 2016, marijuana use among teens in the state increased by 23%, the data showed.
The percentage of teens who said they had used the drug during their lifetimes also increased by 18% following adult legalization.
Recreational marijuana legalization may offer increased opportunities for adolescents and teens to obtain the drug, and the increasing availability of non-smoking products, such as edibles, may prove appealing, as well, researchers said.
"The apparent increase in marijuana use among California adolescents after recreational marijuana legalization for adult use in 2016 is surprising given the steady downward trend in marijuana use during years before legalization," study co-author Mallie J. Paschall said in a press release.
"Recreational marijuana legalization may be contributing to an increase in marijuana use among adolescents in California, but we need to do further research to confirm this," said Pascall, a senior research scientist at the Prevention Research Center of the Pacific Institute for Research and Evaluation in Berkeley, Calif.
To date, 11 states across the country have legalized recreational marijuana use for adults.
For this study, Paschall and his colleagues analyzed data from over 3 million seventh, ninth and 11th graders who participated in the California Healthy Kids Survey from 2010-11 to 2018-19.
The adolescents provided information on their grade, sex, ethnicity, race and lifetime and past-30-day marijuana use.
The marijuana use question was updated in the 2017-2018 and 2018-2019 surveys to include the words "smoke, vape, eat or drink," to include the variety of marijuana products now available.
The 18% increase in lifetime use and 23% rise in past-30-day use seen from the 2017-18 school year to the 2018-19 school year may reflect greater use of vaping products, according to the researchers.
Increases also occurred in past-30-day marijuana use among older adolescents, males and African American and Asian youth who were regular users.
The rise in use of marijuana among younger people may be due to changing feelings about adult use of marijuana following legalization, the researchers suggested.
"I'm interested in whether recreational marijuana legalization for adult use may affect use among adolescents, possibly by changing norms regarding the acceptability of marijuana use, perceived harms of marijuana use, or availability or marijuana to youth," Paschall said.
"Also, we need to know more about how adolescents are getting marijuana and what forms of marijuana they are using, since there is such a great variety of cannabis products available," he said.