regions (superior frontal, cingulate and parahippocampal gyri, amygdala, thalamus, and cerebellum) compared to matched controls at low familial risk for AUD [91]. In this same study, smaller gray matter volumes in many of these regions were associated with elevated externalizing symptoms (attention deficit, hyperactivity, conduct and oppositional defiant disorder symptoms), suggesting that these gray matter differences may predispose individuals to a range of externalizing-spectrum problems, some of which have been previously shown to be genetically correlated with AUD [92, 93]. Thus, some structural brain features appear to meet many of the endophenotype criteria. Systematic gene identification studies for these features may provide evidence for association with AUD and thus become important directions for future research.
