did not differ between the two groups. Another, important factor to consider is that the high risk subjects, despite having a parent who is alcohol dependent, were not alcohol dependent themselves, though they may have the genetic risk to develop alcoholism and/or related disorders. Alcoholism is a complex disorder that is caused by multiple factors, genetic and environmental, and an interaction of both. Not all high risk offspring of alcoholic parents become alcohol dependent, and even if they carry a genetic predisposition, genetic risk alone is not sufficient to cause alcohol dependence (Grant, 1998; Grant and Dawson, 1997; Hingson et al., 2006; Liu et al., 2004a; Liu et al., 2004b). The clinical outcome can be due to several factors, including genetic, familial, social and the interaction of all of these factors; some offspring in high risk families even carry protective factors, preventing them from becoming alcohol dependent themselves (Volkow et al., 2006; Kuehn, 2006). In the future, further studies are required to explore the relationship between the reduced P3 amplitude found in alcoholics and their nonalcoholic offspring, and the lack of N4 differentiation between primed and unprimed stimuli. Similarly, studies are required to identify the protective factors that shield some
