The Positive and Negative Syndrome Scale (PANSS) is a medical scale used for measuring symptom reduction of schizophrenia patients. It is also widely used in the study of psychosis. The name refers to the syndrome of positive symptoms, meaning those symptoms of disease that manifest as the presence of traits, and the syndrome of negative symptoms, meaning those symptoms that manifest as the absence of traits and a series of “general” symptoms for patients with different psychosis. The scale has seven positive-symptom items, seven negative-symptom items and,16 general psychopathology symptom items. Each item is scored on the same seven-point severity scale.
The 30-item PANSS was conceived as an operationalized, drug-sensitive instrument that provides balanced representation of positive and negative symptoms and gauges their relationship to one another and to global psychopathology. Based on two established psychiatric rating systems, it thus constitutes four scales measuring positive and negative syndromes, their differential, and general severity of illness.

Review of five studies involving the PANSS provided evidence of its criterion-related validity with antecedent, genealogical, and concurrent measures, its predictive validity, its drug sensitivity, and its utility for both typological and dimensional assessment.” (Kay SR, Fiszbein A, Opler, LA, 1987)