The variable results of positive-negative research with schizophrenics underscore the importance of well-characterized, standardized measurement techniques. We report on the development and initial standardization of the Positive and Negative Syndrome Scale (PANSS) for typological and dimensional assessment. Based on two established psychiatric rating systems, 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. It thus constitutes four scales measuring positive and negative syndromes, their differential, and general severity of illness. Study of 101 schizophrenics found the four scales to be normally distributed and supported their reliability and stability. Positive and negative scores were inversely correlated once their common association with general psychopathology was extracted, suggesting that they represent mutually exclusive constructs. 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.

Over 75 years ago, Bleuler (1911) confronted psychiatry with the question of ‘schizophrenia’ or ‘schizophrenias'. Today we recognise the heterogeneity of the condition, but we are still groping at efforts to clarify the different subtypes or subprocesses. Over the decades there have been various attempts to subclassify schizophrenia and tease apart the syndromes, none of which has been entirely successful. More recently, as a result of the work by Crow (1980) in England and Strausset al(1974) in the USA, it has been proposed that two distinct syndromes can be discerned from the phenomenological profiles. The positive syndrome consists of productive features superadded to the mental status, such as delusions, hallucinations, and disorganised thinking. The negative syndrome represents absence of normal functions, such as deficits in the cognitive, affective, and social realms.

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Research and treatment of schizophrenia have been impeded by its heterogeneity and the lack of well-standardized methods for a comprehensive assessment of symptoms, including positive and negative dimensions. To study symptom profiles, therefore, we standardized and administered a well-operationalized 30-item psychiatric symptom scale to 240 schizophrenic inpatients. Principal component analysis suggested a pyramidlike triangular model of uncorrelated but nonexclusive syndromes that encompassed the spectrum of psychopathology. Negative, positive, and depressive features constituted divergent points of a triangular base, and excitement made up a separate vertical axis. Paired syndromes could account for symptoms of the paranoid (positive-depressive), disorganized (positive-negative), and catatonic (negative-depressive) diagnostic subtypes. The transversal positions in this model suggested polarized dimensions in schizophrenia, including a prognostic axis (depression-cognitive dysfunction). The findings imply that (1) negative and positive syndromes show factorial validity and distinction from depression but, alone, are insufficient to accommodate the full diversity of symptoms; (2) schizophrenic subtypes derive from a hybrid between unrelated but co-occurring dimensions that may define the fundamental elements of psychopathology; and (3) the pyramidical model is of heuristic value. The results help to clarify the heterogeneity of schizophrenia and to illuminate the path toward syndrome-specific treatments.

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Positive and negative syndromes were studied in relation to demographic, historical, genealogical, clinical, psychometric, extrapyramidal, and follow-up measures of 101 chronic schizophrenic patients. The criterion scales proved to be reliable, normally distributed, and strongly correlated with general psychopathology, but otherwise inversely related to one another. Multiple regression analysis identified sets of 4-6 independent variables that explained 74%-81% of the scales' variance. A positive syndrome was associated chiefly with productive features, family history of sociopathy, more previous hospital admissions, and longer in-patient stay during the 30-month follow-up period. A negative syndrome correlated with deficits in cognitive, affective, social, and motor spheres, higher incidence of major psychiatric illness but less affective disorder among relatives, lower education, and greater cognitive developmental impairment. The results underscore the importance of genetic and biodevelopmental variables for understanding schizophrenic syndromes.

The positive-negative distinction has emerged as a meaningful basis for understanding the heterogeneity of schizophrenia and treatment alternatives, but its delineation requires carefully devised, well validated techniques. This article considers the psychometric requisites for such an instrument and describes 30 criteria associated with operationalization, scale construction, and standardization. Six prominent positive-negative scales are compared on these criteria, and most are found deficient in terms of: a formalized interview procedure; detailed definitions for levels of symptom severity; exclusion of "secondary" negative symptoms; comparative scales to assess positive symptoms, depression, and global severity of illness; broad sampling of negative symptoms; large scale standardization studies; and determination of multiple facets of reliability and validity. The Positive and Negative Syndrome Scale (PANSS) is described as an effort to approach these principles of test standardization, and its clinical and research applications are discussed.