Alcohol dependence is a complex disorder arising from a variety of predisposing factors. One such factor is an intermediary phenotype, or endophenotype, that represents an individual’s level of response to alcohol (Schuckit, 1994). Individuals who require higher doses of alcohol to achieve an effect have a low level of response (low LR) and tend to escalate their alcohol intake, increasing their risk for dependence (Schuckit et al., 1997b; Schuckit et al., 2006; Schuckit et al., 2007).
