Because we demonstrate attitudinal shifts (i.e., perception of risk) around the time of medical marijuana expansion in Colorado, a remaining question is whether those attitudinal shifts will subsequently result in strong or persistent behavioral shifts. Past work has supported that changes in perceived risk about drugs may sometimes precede change in actual use by several years (Bachman et al., 1990). We present data for only one post-2009 time period (2010-11) but as additional years of the NSDUH become available they will provide greater clarity on whether these early changes in marijuana-use-related outcomes (e.g., increase in past-year use (18-25 year olds) and recent Colorado-vs.-NMMS differences in marijuana abuse/dependence prevalence (12-17 year olds, 18-25 year olds)) represent minor year to year fluctuations in estimates or portend sustained changes.
