Is the PANSS Being Used Properly?

July 18, 2011

The PANSS: a long ongoing debate in the psychiatric community revolves around its efficiency due to mathematical properties.

The Positive and Negative Syndrome Scale (PANSS) is one of the most significant rating instruments for patients with schizophrenia, but a long ongoing debate in the psychiatric community revolves around its efficiency due to its mathematical properties.

All thirty items in the PANSS range from one to seven, resulting in a minimum total score of thirty; this implies that the PANSS is an interval scale. For such scales, basic calculation of relative changes is not fitting. In order to calculate outcome criteria based on a percent change as the widely accepted response criterion, the scale has to be altered into a ratio scale beforehand.

Recently, various publications have focused on the drawback of ignoring the scale level (interval vs. ratio scale), as this action can mislead a physician through a set of mathematical problems and potentially result in incorrect findings concerning the efficacy of the treatment.

A Pubmed search was performed based on the PRISMA statement of the highest-ranked psychiatric journals (search terms "PANSS" and "response"). All articles possessing percent changes were included, and methods of percent change calculation were analyzed.

The findings of this search showed that the majority of authors (62%) in fact use incorrect calculations in the PANSS; the method of calculation was not explained in depth in the manuscript for most cases.

The researchers concluded that these alarming results emphasize the necessity for standardized procedures for PANSS calculations.