The Brief Negative Symptom Scale: Validation in a multicenter Brazilian study

Negative symptoms are a core feature of schizophrenia. The Brief Negative Symptom Scale (BNSS) is a scale developed to measure negative symptoms in schizophrenia.

The present study aimed to examine the construct validity of BNSS, by using convergent and divergent validities as well as factor analysis, in a Brazilian sample of 111 outpatients diagnosed with schizophrenia by DSM-5. Patients were evaluated by the Brazilian version of the BNSS and positive and negative subscales of the Positive and Negative Syndrome Scale (PANSS).

Assessment of patients by both instruments revealed an excellent internal consistency (Cronbach's alpha = 0.938) or inter-rater reliability (ICC = 0.92), as well as a strong correlation between BNSS and Marder negative PANSS (r = 0.866) and a weak correlation of the instrument with the positive PANSS (r = 0.292), thus characterizing convergent and discriminant validities, respectively. The exploratory factor analysis identified two distinct factors, namely, motivation/pleasure and emotional expressivity, accounting for 68.63% of the total variance.

The study shows that the Brazilian version of the BNSS has adequate psychometric properties and is a reliable instrument for the assessment of negative symptoms in schizophrenia, either for clinical practice or research.