Contrary to our hypothesis, FHP youth did not show altered white matter architecture in tracts subserving frontoparietal circuitry, suggesting that myelination alone cannot explain frontoparietal connectivity disparities. Rather, variations or delays in synaptic transmission may account for differences in frontoparietal connectivity. The lack of white matter differences between substance-naïve FHP and FHN youth supports prior cross-sectional studies showing abnormal white matter microstructure in adolescent binge drinkers, which related to hangover symptoms (McQueeny et al., 2009). Escalation to heavy alcohol use and resulting withdrawal symptomatology, as opposed to familial risk, might be one contributing factor to the reduced white matter integrity observed among heavy drinking youth.
