Alcohol consumption was measured as a composite of five indicators of heaviness of alcohol use over the lifetime, represented by a single factor derived through factor analysis (see Agrawal et al., 2009 and Grant et al., in press). Items comprising the factor and their corresponding factor loadings are as follows: density (i.e., quantity per week multiplied by frequency per week) of consumption during period of heaviest drinking (0.92), frequency of intoxication during period of heaviest drinking (0.68), maximum number of drinks ever consumed (0.76), frequency of heavy episodic drinking during period of heaviest drinking (0.79) and maximum number of drinks consumed before having an effect during period of heaviest drinking (0.73). (To adjust for skewness, the natural logarithm of the tolerance, density of heaviest use, and maximum drinks measures were used in the factor analysis.) The resulting continuous factor score was divided at 20% intervals (separately for females and males) and re-coded into a 5-level ordinal variable. Alcohol use was nearly universal in the sample, with 98.9% of women and 98.7% of men reporting consumption of one or more drinks over the lifetime.
