Diagnostic assessment of lifetime history of AD was ascertained from the adapted SSAGA interview data. Alcohol dependence was diagnosed by computer algorithms based on the criteria of the Third Revised (DSM-IIIR) and Fourth (DSM-IV) Diagnostic and Statistical Manuals of the American Psychiatric Association (American Psychiatric Association, 1987; American Psychiatric Association, 1994). Similarly, DSM-IV alcohol abuse was assigned by computer algorithm. In addition to the dichotomous definition of AD, more informative (quantitative) measures were calculated and a summary of the alcohol-related traits examined in this study is given in Table1: Number of criteria met for DSM-IIIR (sumAD3r) and DSM-IV (sumAD4) alcohol dependencePrincipal component factor analysis of the 7 criteria for DSM-IV (one factor with an eigenvalue >1; factAD4) and 9 criteria for DSM-IIIR (two factors had an eigenvalue >1; factAD3r_1 and factAD3r_2): the factAD4 factor accounted for 37.7% of the variance in the symptom count variable while the factAD3r_1 and factAD3r_2 scores accounted for 34.5% and 13.0%, respectively.Alcohol consumption: frequency and quantity of alcohol consumption; maximum number of alcoholic drinks consumed in a single day ever and in a single day within the past 12 months.
