Effects of Gender and Binge Drinking on Hippocampal Structure of Young Adults

Alcohol is one of the most used drugs amongst young adults. The Substance Abuse and Mental Health Services Administration (SAMHSA) found in a 2017 national survey that 36.9% of young adults between the ages of 18 and 25 engaged on binge drinking in the past month. This is a concern because studies have showed that the developing brain, but especially the hippocampus, is vulnerable to the damaging effects of alcohol. The aim of this study was to examine the relationship between binge drinking, gender, and hippocampal volume in young adults. There were 39 participants (59% female, 71.8% white) aged 18-25 selected from a parent study. After 1 week of abstinence from alcohol and other substances, participants underwent a brain MRI scan, battery of neuropsychological tests, questionnaires, drug use interview, and toxicology/pregnancy testing. A series of multiple regressions was conducted to examine whether binge alcohol use (as defined by past year binge episodes, past year binge drinks, and past 3-month maximum drinks) and the interaction of gender with binge alcohol use predicted hippocampal volume. Covariates included age, total brain volume, and past year cannabis and cigarette use. The interaction of past year binge episodes*gender significantly predicted right hippocampal (R-HC) volume (p=.015) and marginally predicted left hippocampal (L-HC) volume (p=.080). With greater past year binge episodes, females exhibited larger L-HC (marginally) and R-HC volumes while displayed smaller L-HC (marginally) and R-HC volumes. Past year binge drinks*gender significantly predicted R-HC volume (p=.017). With greater past year binge drinks, females exhibited larger R-HC volumes while males exhibited smaller R-HC volumes. Past 3-month maximum drinks, as well as its interaction with gender, did not predict hippocampal volumes. Inconsistent with previous research, males exhibited smaller hippocampal volumes with greater past year binge drinking behavior, while females demonstrated the opposite effect. These findings should be replicated in a larger, longitudinal sample