Lycoming researchers find trend of mixing alcohol and energy drinks leads to increased alcohol consumption

A team of faculty and student researchers at Lycoming College recently set out to address the growing trend of mixing caffeinated energy drinks with alcohol and whether the practice leads to higher intake of alcohol. Their findings on this significant public health concern are detailed in a paper entitled, “Caffeine Increases Alcohol Self-Administration, an Effect that is Independent of Dopamine D2 Receptor Function,” which was recently published in the peer-reviewed journal Alcohol.

Authored by Sarah Holstein, Ph.D., assistant professor of psychology at Lycoming College, psychology major Gillian Barkell ’19, and biology and psychology double-major Megan Young ’20, the publication evaluates the mechanisms by which caffeine, as found in energy drinks, may increase alcohol drinking and lead to risky patterns of intake. The team’s research posits that caffeine-induced increases in alcohol drinking may be mediated, in part, by caffeine increasing the pleasurable effects of alcohol. The study demonstrates that rats will not only drink more alcohol when under the influence of caffeine, but will also work harder and exert considerably more effort for alcohol when under the influence of caffeine. These effects appear to be specific to alcohol, as caffeine does not increase self-administration of, or motivation for, a non-drug solution in rats. The paper also demonstrates that the dopamine D2 receptor, which has been proposed by some researchers to mediate caffeine induced increases in drug reward, does not appear to contribute to caffeine’s reinforcement enhancing effects.

Holstein’s interest in caffeine-alcohol interactions arose from a conversation with a student who expressed an interest in the mechanisms of action by which caffeine and alcohol work in the brain. Holstein found that little research had been conducted on why caffeine increases alcohol intake, and with the help of Barkell, began evaluating this research question in the lab. Acting as a senior research assistant, Barkell made significant contributions to, and even wrote her honors thesis, on the project. The work earned her awards from both the Lehigh Valley Society for Neuroscience and the Faculty for Undergraduate Neuroscience.

“One of the things I love about psychology and neuroscience is that for all that we know, there are so many questions still remaining,” said Holstein. “At Lycoming, students have the opportunity to work one-on-one with faculty to tackle these unanswered questions and to put what they have learned in the classroom into practice in the lab. It is increasingly common to see graduate programs requiring research experience for admission (particularly Ph.D. programs). Student involvement in faculty-led research can be a critically important training tool for opening doors to graduate study.

“Students bring with them an excitement for the process, and to be involved in the generation of new knowledge is a pretty awesome experience to have as an undergraduate student. Students also bring with them a wealth of personal experiences and new research questions that help shape our research trajectory.”

Both Barkell and Young learned about research opportunities in Holstein’s classes, and their participation was made possible through various grants and fellowships offered to Lycoming students, including the Joanne and Arthur Haberberger Fellowship, the Arthur A. Haberberger Chairman’s Endowed Student-Faculty Research Program, and George B. Gaul Endowed Student-Faculty Research Program. The research was supported by additional Lycoming students, many of whom were also supported by these programs, including Krista Brady ’21, Angela Cardillo ’20, Emily Frantz ’21, Logan Gregory ’21, Erik Homberger ’19, Megan McVeety ’18, Ashmita Mukherjee ’18, Kelly Rogawski ’19, Elle Sarracco ’21, Morgan Valle ’18, and Lydia Yorks ’21, Abigail Bracken ’22, and Emily Frantz ’21.

Barkell is currently working toward a doctoral degree in behavioral and integrative neuroscience at the University of North Carolina at Chapel Hill, and Young is currently working while pursuing graduate research opportunities in neuroscience. Despite graduating from Lycoming, their work in Holstein’s lab lives on through the work of others. “Once we can return safely to the lab, we will further explore the impact of caffeine on alcohol drinking and reward so that we can better understand how caffeine may promote a loss of control over alcohol drinking. The best thing about research is that as soon as we answer one question, many more arise,” said Holstein.

The study can be read in full at https://www.sciencedirect.com/science/article/pii/S0741832920303165?via=ihub#tbl1.