Annual past-year prevalences of marijuana use, DSM-IV marijuana use disorder, and marijuana use disorder among past-year users (conditional prevalence) are plotted in the Figure. Although the trends are not necessarily linear, we fitted each series to a trend line to evaluate the average annual change between 2002 and 2013. The trend for prevalence of marijuana use was positive and significant (β=0.021; 95% CI: 0.017, 0.025; p<0.001), reflecting a relative increase of 19%. The trend for prevalence of marijuana use disorder was flat (β=0.006; 95% CI: −0.015, 0.003; p=0.23). There was a net decrease in the conditional prevalence of marijuana use disorder (β=−0.018; 95% CI: −0.027, −0.009; p <0.001). The Table lists prevalence estimates for each outcome for the years 2002 and 2013, along with comparable NESARC results.
