Only a handful of published findings document changes temporally associated with medical marijuana laws using epidemiological datasets. Using the second wave of National Epidemiologic Survey on Alcohol and Related Conditions collected in 2004-5, Cerdá et al (2012) found that the prevalence of adult marijuana use, abuse and dependence was higher in states with medical marijuana laws compared to those without. Wall and colleagues (2011) using years 2002-8 of the National Survey on Drug Use and Health (NSDUH), showed a higher prevalence of adolescent marijuana use and lower perceptions of riskiness of use in states with medical marijuana laws compared to those without. Harper et al. (2012) replicated and extended the work of Wall et al. concluding that passage of medical marijuana laws had little impact on the prevalence of marijuana use or perceived risk; however, these results were based on findings from only 5 of the 16 states with existing medical marijuana laws which reduced its generalizability (Wall et al., 2012). Most recently, using the Youth Risk Behavior Survey for Montana, Rhode Island, Michigan and Delaware, Lynne-Landsman and colleagues examined
