BACKGROUND: Current initiatives to update diagnostic criteria for alcohol use disorders (AUDs) have stimulated dialogue about the usefulness of indicators of alcohol consumption in the diagnosis of AUDs. METHODS: This study used Rasch model analyses to examine the properties of alcohol consumption descriptors and AUD symptoms among 3382 treatment-seeking adolescents, aged 12-18 years, in the DATOS-A (United States Department of Health and Human Services, 1993-1995) baseline assessment, and evaluated the predictive validity of different scoring methods (with and without alcohol consumption) for 12-month alcohol involvement. RESULTS: Rasch model analyses supported the unidimensionality of indices of alcohol consumption and AUD symptoms. Test information functions showed that adding consumption items provides further information at all points of the alcohol involvement severity spectrum. Combining AUD symptoms with indices of alcohol consumption provided better prediction of alcohol involvement after treatment than either AUD symptom counts or DSM-IV dependence diagnosis alone. Differential item functioning (DIF), however, was observed for select items. Generally, indices of drinking "too much too fast" were more severe for females, African Americans and Hispanics, while the opposite was true for items measuring "too much too often". For age, "too much too often" items were more severe for the younger (12-14 years) age group, and AUD symptoms were more severe for the older (15-18 years) age group. CONCLUSIONS: Indices of alcohol consumption can be validly scaled along with AUD symptoms in this population, and their inclusion provides statistical measurement advantages. Nevertheless, caution is necessary in using consumption items in measuring alcohol involvement due to DIF observed across sex, race and age.
BACKGROUND: Current initiatives to update diagnostic criteria for alcohol use disorders (AUDs) have stimulated dialogue about the usefulness of indicators of alcohol consumption in the diagnosis of AUDs. METHODS: This study used Rasch model analyses to examine the properties of alcohol consumption descriptors and AUD symptoms among 3382 treatment-seeking adolescents, aged 12-18 years, in the DATOS-A (United States Department of Health and Human Services, 1993-1995) baseline assessment, and evaluated the predictive validity of different scoring methods (with and without alcohol consumption) for 12-month alcohol involvement. RESULTS: Rasch model analyses supported the unidimensionality of indices of alcohol consumption and AUD symptoms. Test information functions showed that adding consumption items provides further information at all points of the alcohol involvement severity spectrum. Combining AUD symptoms with indices of alcohol consumption provided better prediction of alcohol involvement after treatment than either AUD symptom counts or DSM-IV dependence diagnosis alone. Differential item functioning (DIF), however, was observed for select items. Generally, indices of drinking "too much too fast" were more severe for females, African Americans and Hispanics, while the opposite was true for items measuring "too much too often". For age, "too much too often" items were more severe for the younger (12-14 years) age group, and AUD symptoms were more severe for the older (15-18 years) age group. CONCLUSIONS: Indices of alcohol consumption can be validly scaled along with AUD symptoms in this population, and their inclusion provides statistical measurement advantages. Nevertheless, caution is necessary in using consumption items in measuring alcohol involvement due to DIF observed across sex, race and age.