Cannabis' Impact on Alcohol Consumption

Cannabis' Impact on Alcohol Consumption: Integrating Laboratory and Ecological Momentary Assessment Methods

This study employs a repeated measures experimental design to examine the effect of THC-dominant dose of cannabis and CBD-dominant dose of cannabis, relative to placebo, on subsequent drinking in an alcohol choice task in which participants choose either to drink or receive monetary reinforcement for drinks not consumed. Cannabis will be administered simultaneously with an alcohol-priming dose or alcohol placebo. The study will enroll up to 350 nontreatment-seeking heavy episodic alcohol drinkers who use cannabis weekly.

This study employs a repeated measures experimental design to examine the effect of THC-dominant (9.53% THC and 0.09% CBD) dose of cannabis and CBD-dominant (0.35% THC and 11.27% CBD) dose of cannabis, relative to placebo, on subsequent drinking in an alcohol choice task in which participants choose either to drink or receive monetary reinforcement for drinks not consumed. Cannabis will be administered simultaneously with an alcohol-priming dose or alcohol placebo. The study will enroll up to 350 nontreatment-seeking heavy episodic alcohol drinkers who use cannabis weekly to obtain the final sample of 200 with complete data. Participants will be tested at a baseline session, during three experimental sessions, and then during a subsequent 4-week period in the natural environment using a smart-phone application. Findings have important implications for cannabis regulatory science and alcohol use disorder treatment by addressing the relative impact of specific cannabinoids as well as contextual risk in cannabis-alcohol co-use.

Mixed factorial design will use a 3 (within-subjects; cannabinoid dose: 9.53% THC/0.06% CBD, 11.27% CBD/0.35% THC, placebo) X 2 (between-subjects; cannabis + an alcohol-priming dose (0.3 g/kg) versus cannabis + alcohol placebo)

367 mg of cannabis plant material with 9.53% THC and 0.09% CBD and 217 mg of placebo cannabis plant material will be mixed and smoked in a handheld pipe

367 mg of cannabis plant material with 11.27% CBD and 0.35% THC and 217 mg of placebo cannabis plant material will be mixed and smoked in a handheld pipe

Alcohol: 0.3 g/kg. Alcohol priming drink is designed to raise blood alcohol levels to 0.03 g/dl and be consumed in 5 minutes. The drink is mixed using 80-proof liquor and juice. Participants are randomized to receive either the experimental alcohol priming dose or alcohol placebo.

Placebo beverage contains only juice and a negligible trace of alcohol for masking. The weight and sex-adjusted volume of alcohol and non-alcohol containing beverages will be equal. Participants are randomized to receive either the experimental alcohol priming dose or alcohol placebo.

Inclusion Criteria: Age 21 to 50 English-speaking cannabis smoking in past two months heavy drinking in past two months in good physical health and weighing < 250 lbs zero breath alcohol at each visit Exclusion Criteria: positive pregnancy test nursing positive urine toxicology screen for drugs other than cannabis interest to quit or receive treatment for cannabis or alcohol use