But opponents still have one trick up their sleeves, and it's proven to be a powerful and effective one: the notion that relaxed regulations on marijuana will lead to a rise in marijuana use among children and teens. Florida voters, for instance, will decide whether to legalize medical marijuana this November. Organizations opposing the measure have built their campaigns around fears about underage use.
The group Don't Let Florida Go To Pot greets visitors to its Web site with the above image, warning that medical marijuana will turn your child into a hoodie-wearing, pot-smoking thug.
More to the point, the notion that medical marijuana leads to increased use among teenagers is flat-out wrong. A new study by economists Daniel Rees, Benjamin Hansen and D. Mark Anderson is the latest in a growing body of research showing no connection -- none, zero, zilch -- between the enactment of medical marijuana laws and underage use of the drug.
The chart above shows the trend in teen marijuana use, as measured by state Youth Risky Behavior Surveys, in Alaska, Arizona, Colorado, Delaware, Maine, Mississippi, Montana, Nevada, New Mexico and Vermont. The x-axis is standardized to track the three-year periods before and after each state passed its medical marijuana law. The lines are essentially flat.
There's little doubt that, like alcohol or tobacco, marijuana use can potentially be harmful to teens, particularly to heavy users. But this paper, like others before it, provides straightforward evidence that there is no link between medical marijuana laws and teen marijuana use.