Acute Consequences Associated With Co-use of Alcohol and Cannabis: A Daily Survey Analysis.

OBJECTIVE

Co-use of alcohol and cannabis has been associated with more total negative consequences than single-substance use, but results have been mixed depending on whether the single substance was alcohol or cannabis. The present study used within-person analyses to examine whether co-use increased the risk for experiencing specific acute negative consequences.

METHOD

College students who were co-users of alcohol and cannabis ( = 341; age = 19.8 years; 51.3% female; 74.8% White) completed 56 days of five daily surveys across two bursts. We used generalized linear mixed effects models to examine the effects of type of substance use day on specific negative consequences, controlling for consumption and covariates.

RESULTS

Relative to both alcohol-only and co-use days, cannabis-only days were associated with decreased likelihood of experiencing hangover, blackout, nausea/vomiting, injury, rude/aggressive behavior, and unwanted sex. Relative to alcohol-only days, cannabis-only and co-use days were associated with an increased likelihood of driving high/drunk. Finally, there was an increased likelihood of hangovers on alcohol-only days compared with co-use days.

CONCLUSIONS

Days with different types of substance use differed in specific consequences. Most of the negative co-use consequences investigated here appear to be driven by alcohol consumption rather than cannabis use. The results also indicated that these young adults were more likely to endorse driving under the influence of cannabis than alcohol. Interventions for co-use should target alcohol consumption to reduce negative consequences such as blackout, injury, rude/aggressive behavior, and unwanted sex and highlight the dangers of driving under the influence of cannabis.