Scales for assessment of depression in schizophrenia: Factor analysis of calgary depression rating scale and hamilton depression rating scale

This study aimed to evaluate the factor structure of Calgary depression rating scale (CDSS) and Hamilton Depression Rating Scale (HDRS) among patients with schizophrenia in acute and remission phase of illness by using exploratory factor analysis. For this, 267 patients with schizophrenia were assessed on CDSS and HDRS. Exploratory factor analysis of CDSS yielded 2 factor models for the whole sample, patients in clinical remission and patients not in clinical remission phase of schizophrenia. Factor analysis of HDRS yielded 3 factor models; however, there was significant difference in the factor structure between those in clinical remission and those not in clinical remission phase of schizophrenia. CDSS total score did not correlate with PANSS positive and negative subscale scores. In contrast, HDRS total score correlated positively with PANSS positive subscale score, PANSS negative subscale score and PANSS general psychopathology subscale score. To conclude, present study suggests while CDSS items separate out into 2 factors, which are stable across different stages of illness, whereas HDRS factor structure appears to be less stable across different stages of illness. Correlation analysis suggests that rating on HDRS may be affected by positive and negative symptoms of schizophrenia, whereas CDSS do not correlate with positive and negative symptoms of schizophrenia.