Several electrophysiological studies have suggested that the deficits observed in alcoholics can be due to trait factors rather than alcohol related state factors (Kamarajan et al., 2005a; Kamarajan et al., 2005b; Porjesz and Begleiter, 1994; Porjesz and Begleiter, 1998). Furthermore, studies have reported that certain ERP components are highly heritable (Begleiter et al., 1998; Hesselbrock et al., 2001; Porjesz et al., 2002a; Porjesz et al., 2002b; van Beijsterveldt and van Baal, 2002) and may serve as endophenotypes for a predisposition to develop alcoholism (Frederick and Iacono, 2006; Kamarajan et al., 2005b; Porjesz et al., 2005). A large scale genome wide linkage study using the same semantic priming – lexical decision paradigm as in the current study showed significant heritability for N400 amplitude in response to primed and unprimed words, and the N400 component showed significant genetic correlations, indicating shared genetic effects (Almasy et al., 1999; Almasy et al., 2001). In addition, using the same paradigm, Roopesh et al. (2009) found that high risk offspring of alcoholics compared to low risk children showed a similar lack of N400 attenuation for primed
