Validation of Turkish version of brief negative symptom scale

Objective: Negative symptoms in schizophrenia have been assessed by many instruments. However, a current consensus on these symptoms has been built and new tools, such as the Brief Negative Symptom Scale (BNSS), are generated. This study aimed to evaluate reliability and validity of the Turkish version of BNSS.Methods: The scale was translated to Turkish and backtranslated to English. After the approval of the translation, 75 schizophrenia patients were interviewed with BNSS, Positive and Negative Syndrome Scale (PANSS), Calgary Depression Scale for Schizophrenia (CDSS) and Extrapyramidal Symptom Rating Scale (ESRS). Reliability and validity analyses were then calculated.Results: In the reliability analysis, the Cronbach's alpha coefficient was 0.96 and item-total score correlation coefficients were between 0.655-0.884. The intraclass correlation coefficient was 0.665. The inter-rater reliability was 0.982 (p<0.0001). In the validity analysis, the total score of BNSS-TR was correlated with PANSS Total Score, Positive Symptoms Subscale, Negative Symptoms Subscale, and General Psychopathology Subscale. CDSS and ESRS were not correlated with BNSS-TR. The factor structure of the scale was consisting the same items as in the original version.Conclusions: Our study confirms that the Turkish version of BNSS is an applicable tool for the evaluation of negative symptoms in schizophrenia.