Fig. 1

Cannabis use in Denver, Colorado among participants with likely alcohol use disorders (AUDs) compared to participants with low risk alcohol use (Non-AUD) during a each year of study enrollment from 2007 to 2016; and b three time-intervals of study enrollment corresponding to pertinent legislative change: prior to cannabis legalization for recreational use (August 2007 to October 2012), after legalization for recreational use (November 2012 to December 2013), and after legalization for sales by retail businesses (January 2014 to April 2016). *Denotes significant group differences in cannabis use (p = 0.006 by Chi-square analysis) for the specified time-interval