We hypothesized that GABRA2 would predict sensation seeking, but not impulsivity, based on results reported by Dick et al. [9]. We also expected that sensation seeking would predict alcohol problems and perhaps conduct problems but not hyperactive–inattentive symptoms, and that impulsivity would predict all three phenotypes. Thus, we expected that GABRA2 would predict alcohol problems and perhaps conduct problems indirectly through sensation seeking and that GABRA2 would not directly predict hyper-active–inattentive symptoms nor indirectly predict hyperactive–inattentive symptoms through impulsivity or sensation seeking.
