Reliability and validity of the Chinese version of the Calgary Depression Scale for Schizophrenia

Objective: The aim of the present study was to determine the reliability and validity of the Chinese version of the Calgary Depression Scale for Schizophrenia (CDSS-C) in schizophrenia patients. Method: One hundred and one inpatients from four mental health units who met DSM-IV criteria for schizophrenia were enrolled. The Positive and Negative Syndrome Scale (PANSS), Hamilton Depression Rating Scale (HDRS-24), Simpson-Augus Rating Scale (SAS), and Barnes Acathisia Rating Scale (BARS) were administered by the first rater, whereas the CDSS-C was assessed by a second independent rater. Results: The internal consistency (Cronbach's = 0.80) and the inter-rater reliability ( coefficient 0.79) were good. The test-retest reliability was high (r = 0.927). The scale had good construct validity, with statistically significant correlations with the HDRS-24, G6 item (depression) of PANSS, and significant weak correlations with the general psychopathology subscale of PANSS. The CDSS-C showed no correlation with the positive and negative subscale of PANSS, the SAS and the BARS. Conclusion: The Chinese version of CDSS is a valid and reliable instrument for the assessment of depression in schizophrenia.