(HealthDay News) – Following legalization of marijuana use, perceived harmfulness of marijuana use decreased and marijuana use increased among eighth and 10th graders in Washington State, according to a study published online Dec. 27 in JAMA Pediatrics.
Magdalena Cerdá, DrPH, MPH, from the University of California Davis School of Medicine in Sacramento, and colleagues used data from 253,902 students participating in a national survey of students in secondary schools to examine the correlation between the legalization of recreational marijuana use in Washington and Colorado in 2012 and the subsequent perceived harmfulness and use of marijuana.
The researchers found that from 2010–2012 to 2013–2015, the perceived harmfulness decreased 14.2 and 16.1% among eight and 10th graders, respectively, in Washington, while marijuana use increased 2.0 and 4.1%. Among states that did not legalize recreational marijuana use, perceived harmfulness decreased by 4.9 and 7.2%, respectively, and use decreased by 1.3 and 0.9%, respectively, among eighth and 10th graders. Comparing Washington with states that did not legalize recreational drug use indicated that these differences were significant for perceived harmfulness and for marijuana use. There were no significant differences among 12th graders in Washington or for any of the surveyed grades in Colorado.
“A cautious interpretation of the findings suggests investment in evidence-based adolescent substance use prevention programs in any additional states that may legalize recreational marijuana use,” the authors write.