Clinician-Reported Negative Symptom Scales: A Systematic Review of Measurement Properties

Background: Negative symptoms of schizophrenia are correlated with reduction of normal function and lower quality of life. They were newly defined by the NIMH-MATRICS Consensus in 2005, dividing the rating tools to assess them into first-generation scales, developed before the Consensus, and second-generation scales, based on the recently introduced definitions. Methods: The COnsensus-based Standards for the selection of health Measurement Instrument (COSMIN) guidelines for systematic reviews were used to evaluate the quality of psychometric data of the first-generation scales that cover the 5 negative symptom domains of the NIMHS Consensus: the Scale for the Assessment of Negative Symptoms (SANS), the High Royds Evaluation of Negativity Scale (HEN), and the Negative Symptom Assessment-16 (NSA-16). Results: The search strategy resulted in the inclusion of a total of 13 articles, 7 for the SANS, 4 for the NSA-16, and 2 for the HEN. For the SANS and the NSA-16, the overall results of the scales’ measurement properties are mostly insufficient or indeterminate. The quality of evidence for the HEN is poor, due to a small number of validation studies/included patients. Conclusions: After applying the COSMIN guidelines, we do not recommend the usage of these first-generation scales to rate negative symptoms. At the minimum they require further validation.