Marijuana use did not increase among teenagers in the states in which medical marijuana has become legal, says a study reported by the New York Times. The analysis is the most comprehensive effort to answer whether decriminalization of marijuana leads more adolescents to begin using it. The study found that states that had legalized medical use had higher prevailing rates of teenage marijuana use before enacting the laws, compared with states where the drug remains illegal. Those higher levels were unaffected by the changes in the law, the study found.
The report in The Lancet Psychiatry covered a 24-year period and was based on surveys of more than one million adolescents in 48 states. The research says nothing about the effect of legalizing recreational use. A primary concern on both sides of the debate over medical marijuana has been that loosening marijuana restrictions might send the wrong message to young people, and make the drug more available and more appealing. Teenagers who develop and sustain a heavy, daily habit increase their risk of having cognitive difficulties later on, several studies suggest. Previous research on usage trends under medical marijuana laws has been mixed. Researchers opposed to legalizing marijuana for medical or other purposes said the study would have to go further to be convincing.