The purpose of this study is to determine whether a genetic propensity for alcoholism can be identified in individuals on the basis of their personality (MMPI, Tellegen personality scales), cognitive styles (Category Test errors), and neurophysiological characteristics (ERP's), amplified by the ascertainment of genetic blood marker data. To this end an association study will be conducted to compare the above assessments in alcoholics, high risk siblings and controls. In addition, a genetic linkage analysis will be performed in 150 individuals drawn from 30 nuclear families to see if the above mentioned assessments segregate with the blood marker data, thereby indicating heritabilities and possible genetic etiologies. The families to be selected will consist of families with both a mother and father of the male alcoholic proband available for study as well as two male full siblings, at least one of whom is free of alcoholism. Thirty additional nuclear families (N=120) will be selected in which the proband and his nuclear family are free of alcoholism. The results of this study are expected to provide markers for the identification of the alcoholism-prone individual.