Spanish validation of the Negative Symptom Assessment-16 (NSA-16) in patients with schizophrenia

Abstract

Introduction: Negative symptoms are prevalent in schizophrenia and associated with a poorer outcome. Validated newer psychometric instruments could contribute to better assessment and improved treatment of negative symptoms. The Negative Symptom Assessment-16 (NSA-16) has been shown to have strong psychometric properties, but there is a need for validation in non-English languages. This study aimed to examine the psychometric properties of a Spanish version of the NSA-16 (Sp-NSA-16).

Material and method: Observational, cross-sectional validation study in a sample of 123 outpatients with schizophrenia.

Assessments: NSA-16, PANSS, HDRS, CGI-SCH and PSP.

Results: The results indicate appropriate psychometric properties, high internal consistency (Cronbach's alpha=0.86), convergent validity (PANSS negative scale, PANSS Marder Negative Factor and CGI-negative symptoms r values between 0.81 and 0.94) and divergent validity (PANSS positive scale and the HDRS r values between 0.10 and 0.34). In addition, the NSA-16 also exhibited discriminant validity (ROC curve=0.97, 95% CI=0.94 to 1.00; 94.3% sensitivity and 83.3% specificity).

Conclusions: The Sp-NSA-16 is reliable and valid for measuring negative symptoms in patients with schizophrenia. This provides Spanish clinicians with a new tool for clinical practice and research. However, it is necessary to provide further information about its inter-rater reliability.

Keywords: Esquizofrenia; NSA-16; Negative symptoms; Propiedades psicométricas; Psychometric properties; Schizophrenia; Síntomas negativos.