Factorial structure of the Positive and Negative Syndrome Scale (PANSS): a forced five-dimensional factor analysis.

We conducted a study on 205 schizophrenic patients in order to explore the factorial structure of the Positive and Negative Syndrome Scale (PANSS). We first documented the validity and reliability of the five-dimensional structure of the PANSS, initially derived from the work of Kay and Sevy and completed by Lindenmayer et al. Some items (stereotyped thinking, mannerisms and posturing, poor attention, lack of judgement, disturbance of volition, and preoccupation) appeared to contribute little to the constitution of the dimensions initially described by Kay and Sevy. Those items were not taken into account in the forced five-dimensional factor analysis. We therefore investigated further the psychometric properties of the PANSS using only the retained items. The validity and reliability of this new five-dimensional structure are discussed.