A common worry for parents in states where medical marijuana has become legal is the impact the laws may have on their child's use of the drug. However, a new study published in The Lancet Psychiatry journal found that marijuana use did not increase among teenagers in the states where it's become legal, as reported in the New York Times.
The new analysis is the most comprehensive effort to date to answer a much-debated question, and found that states that had legalized medical use already had higher prevailing rates of teenage marijuana use before enacting the laws, compared with states where pot remains illegal. The study found that the higher levels of youth use were unaffected by the changes in the law.
The report 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, as compared to states that allow medical use, upon which the study is based.
"We have a war going on over marijuana, and I think both sides have been guilty at times of spinning the data," Dr. Kevin Hill, an assistant professor of psychiatry at Harvard, told the Times. "It's nice to have a scientifically rigorous study to guide policy."
But researchers opposed to legalizing marijuana, whether for medical or other purposes, disagreed, saying the study would have to go further to be more convincing.
"Medical marijuana laws vary drastically across the U.S. and often take years to be implemented, so what we need to see is the longer-term effects of these laws and the accompanying commercialization efforts, which this study does not do," Kevin Sabet, a former Obama administration adviser and president of a group that opposes legalization, told the Times.