including length of abstinence and duration of heavy drinking, ie, the number of years they consumed more than 21 drinks per week (one drink: 355 mL beer, 148 mL wine, or 44 mL hard liquor). A Quantity Frequency Index,67 which roughly corresponds to number of daily drinks, was calculated for each participant. This measure factors the amount, type, and frequency of alcohol usage over the last 6 months (for the nonalcoholic groups), or over the 6 months preceding cessation of drinking (for the alcoholic groups). For one alcoholic participant with a Quantity Frequency Index value lower than three daily drinks, the last 6 months of heavy