(Consortium on the Genetics of Alcoholism) study that compared P3 amplitudes in alcoholics (and their families) from a community sample with the P3s obtained from members of densely affected families ascertained through probands in treatment (Porjesz et al., 1998). In that study it was found that P3 was not reduced in alcohol dependent individuals in the community sample (with low family density) compared to the alcohol dependent individuals from the high density families, despite meeting the same DSM criteria for dependence. Finally, P3b amplitude was negatively correlated with the number of ASPD symptoms, suggesting that the P3b reduction is primarily associated with externalizing symptoms.
