Cannabis use and subjective response to alcohol in the human laboratory

Cannabis is often used in combination with alcohol; yet, whether cannabis use impacts risk factors for alcohol use disorder (AUD) remains unknown. Subjective response (SR) to alcohol represents a biobehavioral risk factor for subsequent heavy drinking and for developing AUD. Given the high prevalence of alcohol and cannabis co-use, it is plausible to hypothesize that cannabis users differ in SR to alcohol compared to non-cannabis users. The purpose of this study is to examine the influence of past-month cannabis use on subjective response to alcohol in the human laboratory.

This study culled data from multiple alcohol administration trials to test whether cannabis users, compared to non-cannabis users, differed in subjective response to alcohol, comprised of four domains: stimulation, sedation, negative affect, and craving. Non-treatment-seeking heavy drinkers (N = 168) completed a battery of self-report scales of mood and alcohol/cigarette/cannabis use and problems. All participants completed an intravenous alcohol administration session wherein SR domains were measured at the following breath alcohol concentrations (BrAC): baseline (i.e., 0), 20, 40, and 60 mg%.

Multilevel statistical analyses revealed that cannabis users had a greater reduction in negative affect during alcohol administration, compared to non-cannabis users. No significant differences were found for the other SR domains.

Using a large sample and advanced data analytic methods, this study extends the literature by suggesting that cannabis users are more sensitive to alcohol-induced reductions in negative affect compared to non-cannabis users. This work extends research on how cannabis use may influence risk factors for AUD, such as subjective response to alcohol.