SPECIFICITY OF THE CALGARY-DEPRESSION-SCALE FOR SCHIZOPHRENICS

This study sought to determine the specificity of the Calgary Depressi on Scale (CDS), a depression rating scale for schizophrenics. The spec ificity is the degree to which the scale assesses depression rather th an negative or extrapyramidal symptoms. Subjects were 100 outpatients (OP) and 50 inpatients (IP) meeting DSM-III-R criteria for schizophren ia. Negative symptoms were assessed with the Positive and Negative Syn drome Scale (PANSS); extrapyramidal symptoms were assessed with the Si mpson Angus Scale (SA) and depression with the CDS. Results were that the CDS showed no correlation with SA, but weak (0.33) statistically s ignificant correlations with the PANSS negative symptom score in inpat ients but not outpatients. Confirmatory factor analysis using Lisrel 6 .0 showed that the model hypothesizing specificity of depression, nega tive symptoms and extrapyramidal symptoms, was significant, with a goo dness of fit index of 0.89 and a root mean square residual of 0.07. It is concluded that the CDS achieves a useful degree of separation betw een measures of depression, negative and extrapyramidal symptoms in su bjects with schizophrenia, when combined with the other measures used in this study.