Psychometric properties of the positive and negative syndrome scale (PANSS) in schizophrenia

We analyzed the psychometric properties of the Positive and Negative Syndrome Scale (PANSS) in a sample of 100 DSM-III-R schizophrenic patients. Our findings coincided with the results of Kay's group in the following points: (1) the PANSS scores were normally distributed; (2) the positive and negative scales showed good interrater reliability; (3) positive and negative syndromes are independent constructs; (4) the positive and negative scales held a high concurrent validity in relation to the Scale for the Assessment of Positive Symptoms and the Scale for the Assessment of Negative Symptoms; and (5) although positive and negative syndromes showed factorial validity, they were not sufficient to account for the whole of the schizophrenic symptoms. Unlike Kay's group, we found a modest internal consistency of the positive scale, indicating that it is composed of several independent components. The data suggest that the distinction between positive and negative symptoms is an oversimplification, and that schizophrenic symptoms can be better conceptualized as composed of, at least three dimensional syndromes: positive, disorganized, and negative.