In order to appropriately model the shared variance between the alcohol dependence severity indices (ADS, PACS, Symptom Count, DrInC-2R, and CIWA-Ar) and to minimize the number of statistical tests, a principal components analysis was conducted on the full sample of problem drinkers (n = 295) to derive factor scores capturing alcohol problem severity across a range of domains. The principal factor method followed by promax (oblique) rotation revealed one meaningful factor (Eigenvalue = 2.749) with each index loading onto the factor at .40 or greater and accounting for 55% of the total variance. The second factor fell below the 1.0 cut off, thus only the first factor was retained and interpreted to represent severity of alcohol dependence. Participants’ scores on this factor were used in analyses of the secondary aim regarding alcoholism severity and responses to alcohol. Factor loadings are presented in Table 1.
