The results of this report fit the notion that the P3AR-alcoholism risk association cannot be accounted for by the deleterious effects of AAU. Previous studies have demonstrated that preexisting alcohol use is not necessary for P3AR by examining alcohol naïve adolescents (Begleiter et al., 1984; Berman, Whipple, Fitch, & Noble, 1993; Hill, Muka, Steinhauer, & Locke, 1995; Polich, Pollock, & Bloom, 1994) as early as age 8 (Viana-Wackermann et al., 2007). Longitudinal designs have demonstrated that P3AR predates the future development of alcohol use behaviors even in alcohol-naïve adolescents (Berman, et al., 1993). This study contributes to the literature by suggesting that, in this community sample of adolescent twins, neither P300 amplitude nor its association with AAU is modified by AAU. The finding that P3AR correlates with, but is not caused by, AAU is also generally consistent with the notion that P300 amplitude is an endophenotype for a broad range of disinhibited behavior, of which AAU is just one expression (Carlson et al., 1999; Hicks, et al., 2007; Patrick, et al., 2006). Adolescence is a critical period for brain development
