including the NSDUH (Grucza et al., 2007) and b) most importantly for the present purpose, we found the same relationship between medical marijuana laws and marijuana use in both the NESARC and the NSDUH. Third, the NESARC only released information regarding state of residence at Wave 1. While movement between waves could have led to misclassification of a subset of respondents, related research finding a significant relationship between minimum drinking age laws based on the state of birth and current substance use disorders indicates that misclassification may not be differential by state legalization status (Norberg et al., 2009). Fourth, we examined the relationship between state legalization by 2004 and marijuana abuse/dependence, and thus excluded four states that have legalized medical marijuana since 2004. To determine whether this affected our results, we re-did the NSDUH analysis using 2007-2008 data, adding the 2 states (Rhode Island and New Mexico) that legalized medical marijuana between 2004 and 2007. The results were not significantly different from those produced from the 2004-2005 data (P>0.05) and are available upon request. Finally, we compared states by legalization status. Future studies need to assess the variation in marijuana use related to heterogeneity of the laws across states, since
