Validation of the traditional script Chinese version of the brief negative symptom scale

Abstract

Negative symptoms are a core feature of schizophrenia and account for much of the long-term morbidity and poor functional outcome of people with schizophrenia. The Brief Negative Symptom Scale (BNSS) was developed to address the main limitations of the existing scales for the assessment of negative symptoms. The BNSS has been translated into Italian, Spanish, German, Turkish and simplified Chinese versions with excellent psychometric properties. In this study, a Chinese (traditional script) version of the Brief Negative Symptom Scale (C-BNSS) was developed and validated to facilitate future research on the Chinese population in Hong Kong. Psychometric properties were examined in 149 individuals with schizophrenia. The C-BNSS showed excellent internal consistency (α = 0.96), high inter-rater reliability (intra-class correlation = 0.98), and high test-retest reliability (Spearman's r = 0.96). Convergent validity was supported by high correlations between C-BNSS total score and subscales with the Scale for Assessment of Negative Symptoms (SANS), Negative Symptom subscale of the Positive and Negative Syndrome Scale (PANSS), and Global Assessment of Functioning (GAF) score. Discriminant validity was supported by low correlations between the C-BNSS total score and the PANSS positive subscale, Calgary Depression Scale, and Simpson-Angus Scale for extrapyramidal symptoms. The C-BNSS showed a five- factor structure on Confirmatory Factor Analysis (CFA), confirming findings of previous studies. Findings indicate that the C-BNSS demonstrates excellent psychometric properties, which are comparable to the original English version. It is a promising instrument for use in clinical trials as well as in clinical practice.

Keywords: Brief negative symptoms scale; Negative symptoms; Schizophrenia.