1984; Begleiter et al., 1987; Whipple et al., 1988; Whipple et al., 1991; Hill and Steinhauer, 1993; Steinhauer and Hill, 1993; Hill et al., 1995). However, it must be stated that P3 reduction in high risk subjects, as a phenomenon, is not consistent or ubiquitous in the literature, but often with equivocal as well as subgroup-specific findings, and has been found to be strongest in younger males (for a meta-analysis, see Polich et al., 1994). For example, some studies reported that P3 reductions were observed only in boys of alcoholic parents (e.g., Hill and Steinhauer, 1993), while other studies found the effect in both genders (e.g., Porjesz et al., 1996). Similarly, this effect has been found to be stronger in younger subjects (e.g., Begleiter et al., 1987; Polich et al., 1994) but still robust in adolescents/young adults (O’Connor et al., 1987; Porjesz and Begleiter, 1990; Porjesz et al., 1996; Ramachandran et al., 1996; Van der Stelt et al., 1998; Kamarajan et al., 2005b). Possible reasons for these inconsistent and/or subgroup specific findings may include the following: (i) the studies may differ methodologically (in terms of sample characteristics, task paradigms, ERP recording and signal processing, statistical techniques, etc.); (ii) definition of
