Facet theoretic analysis of the Hamilton-D scale.

The items of the HAM-D(17-item version) were analyzed by a nonmetric (ordinal) multi-dimensional scaling procedure (Smallest Space Analysis, SSA-I) and the structure of the test items characterized within the framework of Guttman's facet theory. Two systematic components (facets) were discerned: 'centrality' and 'aspect'. Properties of the facets as well as their relations were assessed and examined empirically by analyzing the inter-relations among different items. The spatial configurations obtained by the scaling procedure were found only partially to fit the expectations derived from the facet-theory model. The facet 'centrality' was found to have a strong overriding influence over the 'aspect' facet. The results suggest the value of a new combination and selection of items reflecting different facets of depression consistently over time.