Measurement of negative symptoms

The issue of the dimensionality of negative symptoms is addressed. In reference to data reported by Lewine, Fogg, and Meltzer (1983), it is suggested that the nonsignificant correlation between a SADS-C negative symptom scale and a NOSIE negative symptom scale, both independently developed using the Rasch model, is evidence for the multidimensionality of negative symptoms. Additional data supporting the multidimensionality of negative symptoms using confirmatory factor analysis is also discussed (Gibbons et al. 1985). A new theory for the structure of negative symptoms is needed, which specifies the number of dimensions, their classification, and their pattern of intercorrelation.