(CNN)Marijuana use among young people in the United States overall has climbed in recent years, but a new paper suggests that in states where recreational marijuana has been legalized, marijuana use among youth may actually be falling.Replay More Videos ... MUST WATCH The politics of pot are changing 02:30 The paper had some limitations, including that only an association was found in the study -- not a causal relationship -- and more research is needed to determine why this association exists. "Because many recreational marijuana laws have been passed so recently, we do observe limited post-treatment data for some of these states," Anderson said. "In a few years, it would make sense to update our estimates as more data become available." The new study appears to contradict some separate state-level studies that suggest marijuana use among teens remains unchanged -- instead of declining -- following legalization, said Bonnie Halpern-Felsher, professor of pediatrics in Stanford University's Division of Adolescent Medicine in Palo Alto, California, who was not involved in the new paper.
Sign up here to get The Results Are In with Dr. Sanjay Gupta every Tuesday from the CNN Health team.