In the abovementioned critical review of alcohol administration studies, Newlin and Thompson (1990) described psychobiological markers as characteristics, other than disease symptoms, that identify individuals who are most likely to develop a specific disorder. Importantly, psychobiological makers should be distinguished from the manifestation of prolonged drinking and there may be multiple psychobiological makers for alcoholism given that this disorder is likely to have a multidimensional etiology. The description of psychobiological markers by Newlin and Thompson (1990) and their putative utility in advancing alcoholism research closely resembles the concept of endophenotypes, as described in the psychiatric literature (Burmeister, 1999; Gottesman and Gould, 2003). A recent review of endophenotypes for alcoholism (Hines, Ray, Hutchison, and Tabakoff, 2005), suggested a number of candidate endophenotypes, such as behavioral and physiological traits (e.g., subjective responses to alcohol, alcohol metabolism, alcohol craving, and electrophysiological measures) and biochemical traits (e.g., monoamine oxidase and β-endorphins). The next section will review the conceptual framework and empirical data suggesting that subjective responses to alcohol constitute useful endophenotypes for alcoholism.
