Kraepelin viewed alcoholism as a symptom complex caused by heritable individual differences in emotional predisposition and volitional control. Recent clinical and genetic research has distinguished subtypes of alcoholics with different personality traits, symptoms, course, mode of inheritance, and response to treatment. The heritable personality traits that influence the initiation, continuation, and severity of alcoholism were examined by interview of a national area probability sample of 1019 non-institutionalized adults across the continental United States of America. We found that harm avoidance inhibits the initiation and frequency of drinking, but increases the risk of developing problems once frequent drinking has begun. Novelty seeking increases the initiation of drinking and the probabilities of frequent and problem drinking. This supports Kraepelin's description of the etiology and course of alcoholism as a symptom complex related to individual differences in emotional predisposition.