Given high peak BrAC values and a relatively smaller standard deviation in peak BrAC for GA/GG relative to AA participants, supplemental analyses examined whether the safety ceiling limited self-administration to a greater extent in GA/GG participants. GA/GG participants triggered the safety ceiling significantly more often during the session compared to AA participants (p = .02), indicating more frequent attempts to further increase aBAC when already approaching 100mg%. This result also implied that GA/GG participants spent a greater proportion of the session with access to alcohol blocked. This possibility was confirmed by analyzing the combined duration of “bar” closures during CASE sessions (GA/GG: M=28.90 [SD=26.50] minutes with access blocked, AA: M=10.85 [SD=19.21] minutes, F [1,36] = 5.31, p < .05). In a model including sex as a covariate, this effect fell short of significance (p = .054).
