Longitudinal Effects of Alcohol Consumption on the Hippocampus and Parahippocampus in College Students

Abstract: Background The hazardous effects of alcohol consumption on both hippocampus and memory have been well established. However, the longitudinal effects of ethanol on the developing brain and related consequences on memory are not well explored. Given the above, we investigated the longitudinal effects of college drinking on hippocampal volume in emerging college adults. Methods Data were derived from the longitudinal Brain and Alcohol Research in College Students (BARCS). A subset of 146 freshman (mean age baseline =18.5 yrs) underwent brain MRI scans at baseline and 24 months later. Four drinking related measures derived from a monthly survey were reduced to a single alcohol use index (AUI) using principal component analysis. Gray matter volumetric change (GMV-c) data were derived using a longitudinal pipeline. Voxel-wise hippocampal/para-hippocampal GMV-c associations with the drinking index were derived using a multiple regression framework within SPM12. Supplementary associations were assessed between GMV-c and memory scores computed from the California Verbal Learning Test (CVLT-II; assessed at the end of the study), and between GMV-c and total alcohol induced memory blackouts. Results Larger AUI was associated with an accelerated GMV decline in the hippocampus/para-hippocampus. Also larger hippocampal volume decline was associated with poorer memory performance and more memory blackouts. Conclusion Our study extends prior cross-sectional literature by showing that heavier drinking burden while in college are associated with greater hippocampal GMV decline that is in turn associated with poorer memory scores, all of which could ultimately have a significant impact on student success.