focused on males; data for female offspring have been less consistent, suggesting a weaker effect (Hill and Steinhauer, 1993; Hill et al., 1995a). Data from the COGA study also showed lower P3 amplitude in female offspring from multiplex alcoholism families, yet to a lesser degree than in males (Porjesz and Begleiter, 1996; Porjesz et al., 1998). In a comprehensive meta-analysis of all published HR versus LR studies at the time, Polich et al. (1994) found that the strongest P3 group differences were obtained in young male offspring with relatively difficult visual tasks and concluded that low-voltage P3 may have predictive value as an index of vulnerability for alcoholism. Thus, the low-voltage P3 component is a robust finding that characterizes individuals at risk for alcoholism, and provides an excellent phenotypic “trait” marker.
