Association of cannabis use-related predictor variables and self-reported psychotic disorders: US adults, 2001-2002 and 2012-2013

ABSTRACT Objective To determine the association of cannabis use-related variables and self-reported psychotic disorders during two time periods (2001-2002; 2012-2013). Methods Logistic regression was used to analyze data from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC, 2001-2002; N=43,093) and NESARC-III (2012-2013; N=36,309). Among those with and without cannabis predictors (any and frequent [≥3 times a week] non-medical use, DSM-IV cannabis use disorders [CUD], cannabis dependence [CD]), standardized prevalence of past-year self-reported psychotic disorders were estimated. Association was indicated by within-survey differences in psychotic disorders by cannabis-related predictor status. Whether associations changed over time was indicated by difference-in-difference tests (contrasts between the surveys). Results In both surveys, self-reported psychotic disorders were significantly more prevalent in those with than those without any non-medical cannabis use (2001-2002: 1.65% vs 0.27%; 2012-2013: 1.89% vs. 0.68%), with similar associations in both periods. Self-reported psychotic disorders were unrelated to frequent non-medical use in 2001-2002 but were significantly more prevalent in those with than without frequent non-medical use in 2012-2013 (2.68% vs. 0.71%), with no significant difference over time. In both surveys, self-reported psychotic disorders were significantly more prevalent in those with than without CUD (2001-2002: 2.43% vs. 0.30%; 2012-2013: 3.26% vs. 0.72%), with no significant differences in the associations over time. Self-reported psychotic disorders were unrelated to CD in 2001-2002 but were significantly more prevalent in those with than without CD in 2012-2013 (8.54% vs. 0.73%), showing a significantly stronger relationship in 2012-2013; similarly, among past-year non-medical cannabis users, the association was significantly stronger in 2012-2013. Conclusions Cannabis-related variables, especially cannabis dependence, remain related to self-reported psychotic disorders. Therefore, clinicians should closely monitor cannabis-dependent users and assess the need for preventive and therapeutic interventions for these individuals.