Men with a family history of alcoholism appear to have a lower intensity reaction to alcohol's effects than those without this family history. This study investigated whether a lower reaction could encourage greater alcohol consumption among family history-positive (FHP) subjects, predisposing them to develop alcohol-related problems. A family history of alcoholism was associated with increased risk of alcohol dependence and abuse among study subjects. Likewise, over half of the FHP's whose reactions to alcohol were low had developed alcoholism at a 10-year followup.