Purpose of the Scale

The aim of the research is to identify the positive and negative symptoms that appear in schizophrenia.

Scale Analysis

The scale was developed by Kay et al., in 1987. It consists of 30 items related to schizophrenia symptoms and is organized into subscales for those that correspond to positive symptoms, negative symptoms, and general psychopathology. Additionally, there are five symptom clusters. Specifically, the scale includes 7 positive symptoms, 7 negative symptoms, and 16 items related to general psychopathology.

Scoring and Statistical Analysis

Scoring is conducted on a seven-point scale, with each item receiving a corresponding score based on its severity. Consequently, a score of 1 indicates “absent,” while a score of 7 indicates “extreme severity.” Therefore, the total score is cumulative, and a higher score indicates more severe problems.

Scale Validity

Regarding the Greek adaptation by Ntonias et al., a measure of construct validity involved the correlations between the positive, negative, and general psychopathology subscales. The correlation coefficient between the positive syndrome scale and the negative syndrome scale was 0.31. Furthermore, the correlation coefficient between the positive syndrome scale and the general psychopathology scale was 0.71, and finally, the correlation coefficient between the negative syndrome scale and the general psychopathology scale was 0.68.

Scale Reliability

The reliability for the two halves of the scale was 0.77. The Pearson r correlation coefficient between raters for individual items ranged from 0.76 to 0.97. The reliability of various items with the subscales and the symptom clusters they belonged to was satisfactory, with the exception of five items that belonged to the general psychopathology subscale. Inter-rater reliability for the positive syndrome was 0.93, for the negative syndrome 0.96, and the composite index was 0.95. Additionally, the corresponding reliability for general psychopathology was 0.96. The inter-rater reliability for the clusters was 0.96 for anergia and 0.97 for thought disturbance. Furthermore, the reliability for activation was 0.84, for hostility 0.92, and for depression 0.92, respectively.

References

Kay, S. R., Fiszbein, A., & Opler, L. A. (1987). The positive and negative syndrome scale (PANSS) for schizophrenia. Schizophrenia Bulletin, 13(2), 261-276.
Kay, S. R., Opler, L. A., & Lindenmayer, J. P. (1988). Reliability and validity of the positive and negative syndrome scale for schizophrenics. Psychiatry Research, 23(1), 99-110.