The maximum number of alcoholic drinks ever consumed in a single 24-hr period appears to have face and empirical validity as a phenotype related to alcoholism. Consuming large quantities in one sitting likely reflects acute or chronic tolerance. Maximum alcohol consumption helps to distinguish alcoholism with physiological features from alcoholism without such features (Schuckit et al., 1998) and is associated with more severe withdrawal symptoms (Schuckit, Tipp, Reich, Hesselbrock, & Bucholz, 1995). It also appears to reflect relative insensitivity to alcohol's negative effects (Schuckit et al., 2005). Furthermore, some alcoholics report that once having had one drink they are unable to resist subsequent drinks. Even nonalcoholic individuals may be susceptible if their risk for alcoholism is elevated; nonalcoholic males with a positive family history of alcoholism rated themselves as less confident in their ability to resist another drink after a placebo than subjects without such a family history (Kaplan, Hesselbrock, O'Connor, & DePalma, 1988). The maximum consumption phenotype may be related to this type of loss-of-control drinking, long considered a cardinal feature of alcoholism (Jellinek, 1960).
