We found no compelling evidence that behaviors that have been speculated to contribute to alcohol use (e.g., executive function, negative urgency, and impulsivity) are associated with prefrontal or insula GMV, leaving the behavioral mechanisms through which these GMVs may influence alcohol use unclear. DLPFC GMV was negatively correlated with delay discounting and using alcohol to cope with stress in our young adult sample (DNS sample) at nominal levels of significance, while these behavior characteristics and DLPFC GMV were unlinked in our young and middle-age adult sample (Tables S9, S10 in Supplement 1). This finding suggests that these behavioral factors may represent mechanisms through which GMV influences alcohol use in adolescence and young adulthood, potentially contributing to continued use, while GMV is uncorrelated with these behaviors as measured in later life. Nonetheless, it is also plausible that these nominally significant findings represent false-positives.
