The 5-factor structure of the Brief Negative Symptom Scale (BNSS) is an excellent fit for study samples of symptoms of patients with schizophrenia across a range of languages and cultures, making it superior to the 2-dimensional model for both examining research in translation and for clinical use in assessment, diagnosis, and treatment, according to a study published in Schizophrenia Bulletin.
This study sought to investigate and validate BNSS-rated negative symptoms using cross-cultural data and determine the correct factorial structures. Analysis examined the fit of 5 separate models: 1) 1-factor, 2) the standard 2-factor model, 3) 3-factor model with external, inner world, and alogia; 4) 5-factor model with blunted affect, anhedonia, avolition, alogia, and asociality; and 5) hierarchical model with second-order factors for diminished expression and motivation and pleasure, along with 5 first-order factors for blunted affect, anhedonia, avolition, alogia, and asociality.
The analytic strategy was to establish calibration samples of BNSS-related negative symptoms factor structures, then cross-validate those samples across languages and cultures. Findings revealed that the 5-factor and hierarchical models were both excellent fits and superior to all other models, with the 5-factor model being a slightly better fit, showing factorial invariance across samples across multiple nations and languages.
Study investigators recognize that these findings have important implications. Because the 5-factor structure for negative symptoms is not culturally bound, this suggests that the 5 domains of anhedonia, asociality, avolition, blunted affect, and alogia reflect core processes that are uninfluenced by language or nationality and are inherent to the diagnosis. They conclude by stating that the next step in research “is to determine if the 5-factor model is valid regardless of sex, negative symptom type, illness stage, or illness severity. Any determination of equivalence or nonequivalence of the 5 domains would be informative about the phenomenology of negative symptoms.”
Ahmed AO, Kirkpatrick B, Galderisi S, et al. Cross-cultural validation of the 5-factor structure of negative symptoms in schizophrenia [published online April 18, 2018]. Schizophr Bull. doi: 10.1093/schbul/sby050