period of heaviest use. Lifetime indices were maximum drinks consumed in a 24-hour period (log-transformed) and maximum tolerance (maximum drinks consumed before becoming drunk, or maximum drinks consumed before feeling any effect for those who had never been drunk; log-transformed). Indices from the 12-month period of heaviest use were typical weekly consumption (typical number of drinks consumed per drinking occasion multiplied by typical frequency of consuming alcohol; log-transformed), frequency of heavy drinking (5 or more drinks on a single occasion), and frequency of drinking to intoxication. Our primary analysis focused on the total number of lifetime AD symptoms endorsed, with a separate conditional clustering variable indicating whether at least 3 AD symptoms had ever occurred within a 12-month period. Per DSM-IV criteria, alcohol abuse was defined hierarchically (i.e., only among respondents who did not have AD).
