State-level rates of marijuana use but not DSM-IV abuse/dependence are publicly available from the NSDUH. The NSDUH collects information from residents aged 12 and older of households, noninstitutional group quarters, and civilians living in military bases, using a 50-state design with an independent, multistage probability area sample for each state. To maximize comparability with the NESARC, we combined 2004 and 2005 NSDUH data and included only respondents aged 18 or older (US Department of Health and Human Services). In 2004, the sample size was 67,760, and in 2005, 68,308 individuals responded to the survey. Each year, NSDUH allocates the sample size equally across three age groups: persons aged 12-17, persons aged 18-25, and persons aged 26 or older, yielding approximately 45,000 in our sample of 18 and older in both years. However, since we conducted state-level analyses with NSDUH, our effective sample size was 50 states per year.
