An early COGA (Consortium on the Genetics of Alcoholism) study that compared P300 amplitudes in community-dwelling individuals with AUDs (but with low family history density of alcohol problems) to those in treatment-seeking members of densely affected families reported no P3b reductions in the community-dwelling sample compared to the high-density sample, despite the fact that all participants, regardless of group, met DSM criteria for dependence (Porjesz et al., 1998). Because those findings are consistent with the current study, it is likely that, despite the limitations of our measure of family history density of alcohol problems, the conclusions arising from our assessment of genetic vulnerability to alcoholism in the current TNAD sample, are true.
