Although not all COA’s exhibit low P3 amplitudes, a larger percentage of COA’s exhibit low P3’s compared with the rest of the population. COA’s from densely alcoholic families are more likely to exhibit low P3 amplitudes than are other COA’s (Porjesz et al. 1996). Furthermore, subjects with family histories of both alcoholism and antisocial personality disorder (ASPD) have reduced P3 amplitudes. ASPD is characterized by a pattern of irresponsible and antisocial behavior, such as physical fighting or stealing, that begins in childhood or early adolescence and continues into adulthood. Both family history of alcoholism and ASPD are factors that increase the risk of developing alcoholism (Hesselbrock et al. 1993). Thus, the low P3 amplitude seems to be a robust finding that characterizes persons at risk for alcoholism and may provide a vulnerability marker for alcoholism.
