Factors that predispose people toward alcohol use disorders (AUDs) are heterogeneous, may operate differently in males and females, and involve both environmental and genetic components [1-3]. Such vulnerabilities include the low level of response (LR), or lower sensitivity, to alcohol [e.g., 4-6]. LR values are genetically influenced (e.g., they correlate higher in close relatives than in unrelated individuals and in identical compared to fraternal twins) [7, 8], and a low LR predicts future heavy drinking [9-11].
