As of 2013, 22 U.S. states and the District of Columbia have legalized marijuana for medical use, 17 states have decriminalized marijuana possession, and two states, Colorado and Washington, have legalized marijuana for recreational use.1 In a recent national opinion poll of adults, the vast majority (77%) reported that marijuana has legitimate medical uses, and more than half (52%) supported the legalization of marijuana for recreational use.2
This rapidly liberalizing environment may support increased acceptance of and use of marijuana among youths.3,4,5 National survey data indicate that marijuana is the most commonly used illicit drug among U.S. teens, with 13% of 8th graders, 33% of 10th graders, and 42% of 12th graders having used marijuana in the past year.6 The perceived risk of using marijuana has been declining.7
We are currently investigating the relations of policy changes regarding marijuana and adolescents' marijuana beliefs and related behaviors. In a recent study we found that the relation between legalization of medical marijuana and youth use and beliefs may be a result of an overall normative environment that is more tolerant of marijuana use, rather than legalization per se. Interventions to prevent youth marijuana use should focus on adult norms regarding use by and provision of marijuana to youths. It is important to develop preventive interventions that are tailored to this changing environment.