The Persian version of the Calgary Depression Scale for Schizophrenia (CDSS-P)

Determining depression symptoms in schizophrenic patients is a challenging process because of a degree of similarity between depression symptoms and negative symptoms and the extrapyramidal side effects of neuroleptic drugs, but it is crucial to evaluate and measure depression among patients with schizophrenia for a better clinical outcome. The Calgary Depression Scale for Schizophrenia (CDSS) is a valid and reliable instrument used for the evaluation of depression in schizophrenia. This study aimed to determine the psychometric properties of the Persian version of CDSS in a sample of people with schizophrenia. Clinical interviews were conducted with 95 schizophrenic patients (40 inpatients and 55 outpatients), who were assessed with the Positive and Negative Syndrome Scale (PANSS), Hamilton Depression Rating Scale (HDRS-17 and HDRS-24 items), and the Calgary Depression Rating Scale (CDSS). Then an exploratory factor analysis was conducted to determine correlations between scales, Cronbach's alpha, and cutoff scores. The factor analysis led to the extraction of a unifactorial solution. The CDSS had significant relationships with PANSS Negative and PANSS General. However, it had no significant relationship with PANSS Positive and the PANSS Total. The CDSS also had significant relationships with HDRS-17 and HDRS-24. In addition, Cronbach's alpha of total score, test-retest reliability, and cutoff score were estimated at 0.86, 0.82, and 8 (sensitivity = 0.79 and specificity = 0.84), respectively. The findings support the CDSS unifactorial approach. Results also showed that the CDSS Persian version had acceptable psychometric properties; thus, it could be employed to evaluate depression among schizophrenic patients.