Characteristics of drinking episodes associated with simultaneous alcohol and cannabis use among underage drinkers in the United States.

BACKGROUND: Simultaneous alcohol and cannabis (SAC) use is associated with more negative consequences than independent use of alcohol or cannabis. Contextual characteristics of drinking episodes are associated with the quantity of alcohol consumed and related risk. This study examined whether drinking contexts may also be associated with SAC use. METHODS: National Survey on Drug Use and Health (NSDUH) 2010-2019 data from past 30-day drinkers aged 12-20 (n = 39,456) were used. A weighted multivariable logistic regression model examined associations between contextual characteristics (alcohol source, number of people, drinking location) and SAC use during their most recent drinking occasion. Models adjusted for survey year, heavy episodic drinking, age, sex, race/ethnicity, student status, and metropolitan area status. RESULTS: More than one-in-five drinkers reported SAC use. Compared to getting alcohol from parents/family, those who took it from a home (OR = 1.51,95 %CI = 1.24,1.84), got it for free another way (OR = 2.30,95 %CI = 2.05,2.59), paid someone else for it (OR = 2.83,95 %CI = 2.46,3.25), or purchased it themselves (OR = 3.12,95 %CI = 2.66,3.67) had higher odds of SAC use. Compared to drinking alone, drinking with more than one person was associated with higher odds of SAC use (OR = 1.36,95 %CI = 1.12,1.66). Compared to drinking in their home, drinking in a bar (OR = 0.51,95 %CI = 0.41,0.64) had lower odds of SAC use, whereas drinking in someone else's home (OR = 1.12,95 %CI = 1.02,1.22), a car (OR = 1.36,95 %CI = 1.04,1.77), or multiple locations (OR = 1.29,95 %CI = 1.09,1.53) had higher odds of SAC use. CONCLUSIONS: Findings suggest that alcohol-related contextual characteristics are associated with SAC use among underage drinkers. Laws addressing underage alcohol consumption, including social host liability and sales to minors laws, may also decrease simultaneous cannabis use.