http://adai.uw.edu/mjsymposium/MarijuanaSymposiumAgendaLinks.pdf SDRG Projects \t\t\t\t \t\t\t\t Current Projects Marijuana Legislation and Changes in Youth Marijuana Use and Related Risk Factors \t\t\t\tThe goal of this project is to understand the impact of marijuana-related legislation (both medical and recreational) on adolescent marijuana and other substance use and related risk factors using time-series analysis of survey data from Colorado, Washington, and Oregon and additional comparison states. The recent legalization of recreational marijuana use for those over 21 years of age in Washington and Colorado and the failure of legalization in Oregon, along with the medical marijuana laws of earlier decades, have changed the legal and normative context for current and future generations of youth. One of the primary concerns for public health is that legalization may lead to more favorable attitudes and norms and lower perceived harm from marijuana use, which have been shown to predict earlier age of marijuana use onset and greater adolescent use, which, in turn, have been associated with a range of negative outcomes, including subsequent drug abuse and dependence and interference with a healthy and successful transition into adulthood. This study uses an interrupted time-series design (ITS), including multiple baseline ITS, to examine statewide survey data from adolescents and thereby assess the long-term patterns of age of onset and youth marijuana use and marijuana-related attitudes, norms, and perceived harm of using marijuana among youth before and after (1) medical marijuana t legalization, and (2) recreational marijuana legalization. Moreover, this study examines the patterns of change in youth alcohol, tobacco, and other drug use over time to assess the plausibility of the so-called substitution effect in which marijuana use substitutes (or, in contrast, exacerbates) other substance use. Given the current paucity of clear scientific evidence, understanding how marijuana legislative changes impact adolescent drug use and development is a pressing necessity and a prerequisite for the design and implementation of effective prevention and intervention services. Study results will inform national and state-level discussions about the potential impact of marijuana legislation on adolescent substance use and developmental risk. \t\t\t\t \t\t\t\tStart Date: 2014 PI: \t\t\t\t\t\tKatarina Guttmannova \t\t\t\t \t\t\t\tProject Director: \t\t\t\t \t\t\t\tFunding: National Institute on Drug Abuse \t\t\t\tPublication SDRG 718 \t\t\t\t\t\t (P) \t\t\t\t\t\t Advance online publication. doi: 10.1111/acer.12942pp \t\t\t\t\t\tGuttmannova, Katarina, Lee, Christine, Kilmer, Jason R., Fleming, Charles B., Rhew, Isaac C., Kosterman, Rick, Larimer, Mary E. \t\t\t\t\t\t(2015). \t\t\t\t\t\tImpacts of changing marijuana policies on alcohol and other drug use in the United States. \t\t\t\t\t\t Alcoholism: Clinical and Experimental Research, (), Advance online publication. doi: 10.1111/acer.12942