Demographic and drinking characteristics were compared between AUD+ and AUD− groups by t-tests and Chi-Square, as appropriate. Acute alcohol responses were analyzed by Generalized Estimating Equations (GEE) (35) models including group, time, and phase with the latter two variables treated as continuous variables. To assess potential nonlinearity over time, models for each alcohol response included linear, square and cubic terms of time. Results revealed that only BAES stimulation (and not sedation, liking or wanting) required the second and third order polynomial terms. This is consistent with prior work showing rapid increases in stimulation during the ascending BrAC limb, followed by an inflection point and sharp declines during the descending BrAC limb (10). GEE models were also used for secondary measures including general subjective response (DEQ feel drug) and physiological effects (heart rate and cortisol secretion) sensitive to alcohol (36–38). The AUD SX subgroups were examined on alcohol responses in GEE models similar to those conducted in the main analysis to examine subgroup, time, and phase effects and their interactions. All GEE models adjusted for age, race, education, FH (39), BrAC (as a time-varying covariate), and the number of baseline AUD symptoms.
