Associations of cannabis use, use frequency, and cannabis use disorder with violent behavior among young adults in the United States

Background: Most violent crimes (52 %) are committed by adults aged 18-34, who account for 23 % of the US population and have the highest prevalence of cannabis use and cannabis use disorder (CUD). We examined whether and how associations of cannabis use, use frequency, and CUD with violent behavior (i.e., attacking someone with the intent to harm seriously) vary by sex in U.S. young adults. Methods: Data were from 113,454 participants aged 18-34 in the 2015-2019 US National Surveys on Drug Use and Health, providing nationally representative data on cannabis use, CUD (using DSM-IV criteria), and violent behavior. Descriptive analyses and bivariate and multivariable logistic regression analyses were conducted. Results: Among U.S. adults aged 18-34, 28.9 % (95 % CI = 28.5-29.2 %) reported past-year cannabis use (with/ without CUD), including 20.5 % (95 % CI = 20.2-20.8 %) with non-daily cannabis without CUD, 4.7 % (95 % CI = 4.5-4.8 %) with daily cannabis use without CUD, 2.1 % (95 % CI = 1.9-2.2 %) with non-daily cannabis use and CUD, and 1.7 % (95 % CI = 1.5-1.8 %) with daily cannabis use and CUD. Past-year adjusted prevalence of violent behavior was higher among males with daily cannabis use but without CUD (2.9 %, 95 % CI = 2.4-2.7 %; adjusted prevalence ratio (PR) = 1.7, 95 % CI = 1.3-2.2) and males with daily cannabis use and CUD (3.1 %, 95 % CI = 2.3-4.0 %; adjusted PR = 1.8, 95 % CI = 1.3-2.4) than males without past-year cannabis use (1.7 %, 95 % CI = 1.6-1.9 %). Adjusted prevalence of violent behavior was higher among females with cannabis use regardless of daily cannabis use/CUD status (adjusted prevalence = 1.6-2.4 %, 95 % CIs = 0.9-3.2 %; adjusted PRs = 1.6-2.4, 95 % CI = 1.3-3.2) than females without past-year cannabis use (1.0 %, 95 % CI = 0.9-1.1 %). Conclusions: Research is needed to ascertain the directionality of the associations between cannabis use and violent behavior and underlying sex-specific mechanism(s). Our results point to complex sex-specific relationships between cannabis use frequency, CUD, and violent behavior and highlight the importance of early screening for and treatment of CUD and of preventive interventions addressing cannabis misuse.