According to a new study published in the American Journal of Public Health, researchers at the University of Florida College of Medicine in Gainseville have determined that the enactment of state medical marijuana laws (MML) does not lead to an increase in teen marijuana use.
The researchers used data from 2003-2011 compiled from the Youth Risk Behavior Survey for the states of Montana, Rhode Island, Michigan, and Delaware. In their conclusions, researchers wrote: "Our results suggest that, in the states assessed here, MMLs have not measurably affected adolescent marijuana use in the first few years after their enactment. Longer-term results, after MMLs are more fully implemented, might be different."
These data confirm the results of other similar studies on MMLs and teen use. In 2012, the German Institute for the Study of Labor published work by university researchers at Montana State, Oregon, and Colorado-Denver entitled "Medical Marijuana Laws and Teen Use". Anderson, Hansen, & Rees examined the same Youth Risk Behavior Survey from 1993-2009, covering then-thirteen medical marijuana states, and concluded "Our results are not consistent with the hypothesis that the legalization of medical marijuana caused an increase in the use of marijuana and other substances among high school students."
Marijuana Policy Project in 2011 updated their study "MARIJUANA USE BY YOUNG PEOPLE: The Impact of State Medical Marijuana Laws" by Karen O'Keefe and Dr. Mitch Earleywine*, where they have made the following conclusions:
In California --- which has the longest-term, most detailed data available --- data shows an overall decrease in teens' marijuana use...
In Washington state (which passed its law in 1998), sixth and eighth graders' current and lifetime marijuana use has dropped significantly...
Data from Oregon (whose law passed in 1998) suggest modest declines in marijuana use among the two grades surveyed...
Data from Alaska (which passed its law in 1998) show a moderate decrease in high schoolers' current marijuana use and a slight decrease in their lifetime use...
In Maine (which passed its law in 1999), available data on teen marijuana use suggest usage has decreased or stayed the same for every age group...
In Hawaii and Nevada (both passed laws in 2000), high schoolers' current and lifetime marijuanause has decreased since the enactment of the state laws.
Colorado (which also passed its law in 2000) is the only state without an in-depth statewide survey; the limited data available suggest a modest decrease in Colorado teens' marijuana usage.
Data from Vermont (which passed its law in 2004) indicate a modest decline in teens' current marijuana use, as well as declines at all surveyed individual grade levels.
Data from Montana suggest a small decline in high schoolers' lifetime marijuana use since the 2004 passage of the
state's medical marijuana law and no change in their current marijuana use.
In Rhode Island (which passed its law in January 2006), lifetime youth marijuana use has decreased slightly since the law passed, though current use has increased slightly.
New Mexico, which enacted a medical marijuana law in April 2007, shows slight increases in current teen marijuana use rates, which coincide with increases at the national level over the same time period.
In Michigan (which passed its law in November 2008), the data show mixed results, with use rates, both current and lifetime, down in ninth and 10th grades, but up in the 11th and 12th grades.
Nationwide, teenage marijuana use has decreased in the more than 14 years since California enacted the country's first effective medical marijuana law.