Twenty states and the District of Columbia have legalized marijuana for certain qualifying medical conditions (ONDCP, 2013) and more than 280,000 individuals are registered for medical marijuana in the United States (Bowles, 2012). In 2012, Colorado and Washington state legalized possession of an ounce or less and recreational use of marijuana for those 21 years of age or older (Johnson, 2012; Gurman, 2012). Such ongoing policy shifts underscore the critical need to provide accurate scientific information to the public on the impact of marijuana medicalization/legalization; the potential impact of such legal and policy changes remains hotly debated.
