Alcoholism is a common, complex disorder with contributions from both genetic and environmental influences and their interactions [41]. The identification of suitable quantitative biological markers that are genetically transmitted could explicate the genetic factors involved in the etiology of alcoholism [42]. One successful approach has been the use of biological markers as “endophenotypes”, or intermediate phenotypes (measurable components, traits or variables along the pathway between disease and distal genotype, that are heritable, correlated with the illness, and are already present in those at risk prior to the onset of the illness [43]). In this regard, (electrophysiological measures such as electroencephalogram (EEG), event-related potentials (ERPs) and event-related oscillations (EROs) provide a rich source of potentially useful and powerful endophenotypes for alcoholism, as they meet these criteria, are quantitative, less complex and more proximal to gene function than traditional diagnoses, and represent important correlates of human information processing and cognition; hence they provide more power to localize and characterize disease susceptibility genes (cf. [42]).
