Concomitant Caffeine Increases Binge Consumption of Ethanol in Adolescent and Adult Mice, But Produces Additive Motor Stimulation Only in Adolescent Animals

Abstract

Background Binge co-consumption of highly caffeinated energy drinks with alcohol (ethanol) has become a common practice among adolescents/young adults and has been associated with an increased incidence of hazardous behaviors. Animal models are critical in advancing our understanding the neurobehavioral consequences of this form of binge drinking. Surprisingly, virtually no work has explored caffeine and ethanol co-consumption or its long-term consequences in adolescent animals. The primary objective of the current study was to extend a previously established mouse model of voluntary binge caffeine and ethanol co-consumption to explore adolescent consumption and responses compared to adults. Methods Adolescent and adult male C57BL/6J mice had daily limited access to caffeine (0.03% w/v), ethanol (20% (v/v), a combined ethanol/caffeine solution, or water for 14 days via the binge-like drinking paradigm, Drinking-in-the-Dark. Home cage locomotor activity was measured during DID in a subset of mice. Following DID, all mice rested for 18 days so that adolescents reached adulthood, whereupon all mice underwent 7 days of continuous access two-bottle choice drinking for 10% (v/v) ethanol or water. Results Co-consumption with caffeine significantly increased ethanol intake and resultant blood ethanol concentrations in both adolescent and adult mice. In addition, adolescent mice exhibited a uniquely robust locomotor stimulant response to caffeine and ethanol co-consumption. Later ethanol intake and preference was not influenced, however, by prior fluid consumption history via DID. Conclusion Together with findings from the human literature, our results suggest that caffeine co-consumption may positively influence binge alcohol consumption in adolescents/young adults. Importantly, this age group may be particularly sensitive to the additive stimulant effects of caffeinated alcohol consumption, an effect which may be related to the high incidence of associated negative outcomes in this population. These observations are particularly concerning considering the heightened plasticity of the adolescent brain.

Red Bull® energy drink increases consumption of higher concentrations of alcohol

“…Researchers argue that caffeine may counteract the depressant effects of alcohol (Arria & O'Brien ; Peacock & Bruno ; Fritz, Companion, & Boehm ; Fritz et al . ). The modulatory and interactive effects of the other energy drink ingredients on alcohol intake and related behavior remain greatly unexplored.…”

“…Similar locomotor results were recently observed in adolescent mice when they were allowed to voluntarily consume alcohol, caffeine or its combination in a limited‐access binge‐like alcohol drinking paradigm (Fritz et al . ).…”

Desire to Drink Alcohol is Enhanced with High Caffeine Energy Drink Mixers

“…Thus, the risks of drinking alcohol may be higher with consumption of AmED when compared to alcohol alone because the perceived stimulation is enhanced with an energy drink mixer. Given the importance of drug‐induced stimulation, it is notable that findings from several animal studies from different laboratories have reported that locomotor stimulation changes are enhanced for alcohol caffeine combinations when compared to either drug alone (Fritz et al., ; Hilbert et al., ; May et al., ). In one study, it was observed that binge consumption of alcohol by both adolescent and adult mice increased with caffeine, but only the adolescent mice exhibited robust locomotor stimulant responses to alcohol caffeine combinations (Fritz et al., ).…”

“…Given the importance of drug‐induced stimulation, it is notable that findings from several animal studies from different laboratories have reported that locomotor stimulation changes are enhanced for alcohol caffeine combinations when compared to either drug alone (Fritz et al., ; Hilbert et al., ; May et al., ). In one study, it was observed that binge consumption of alcohol by both adolescent and adult mice increased with caffeine, but only the adolescent mice exhibited robust locomotor stimulant responses to alcohol caffeine combinations (Fritz et al., ). As such, phase of human brain development and drinking history may be only a few of the important factors to examine in the future in an effort to understand when and by how much desire for alcohol is enhanced with energy drink mixers and how stimulation plays a role in these outcomes.…”

“…Finally, the findings of this research are consistent with the available animal studies that have investigated whether caffeine coadministration with alcohol increases alcohol intake. Results from many different laboratories have demonstrated that moderate doses of caffeine (similar to human consumption of energy drink mixers) increase the intake of alcohol in ad libitum administration models using rats and mice (Dietze and Kulkosky, ; Fritz et al., ; Kunin et al., ; Rezvani et al., ). While these findings might suggest that there is something unique about caffeine in increasing the reinforcing properties of alcohol, it is also possible that all stimulant drugs may have this effect in the presence of alcohol.…”