The homogeneity of the alcohol dependence syndrome: a factorial analysis of the SADD questionnaire.

The Severity of Alcohol Dependence Data (SADD) questionnaire was administered under different conditions to three groups of patients in Leeds, Derry and Omagh. The results were then factor analysed using both exploratory and confirmatory procedures. There was a consistent and strong first factor which suggests that with some small modifications the SADD is a unidimensional scale. The results are interpreted as providing further evidence for the homogeneity of the alcohol dependence syndrome.