Should the PANSS Be Rescaled?

Abstract

The design of the Positive and Negative Syndrome Scale (PANSS) with item levels ranging from 1 to 7 leads to the trivial result that the 30-item scale's zero level (no symptoms) is 30. This causes serious problems when ratios are calculated which always implicitly depend on a natural zero point (equals 0). Recent publications concerning efficacy of antipsychotics correctly suggest a subtraction of 30 points to every PANSS before calculating percent change (PC). Nevertheless, the traditional approach using uncorrected scores is still in common practice. This analysis aims to clarify which approach is the most appropriate from a statistical perspective.For analysis, data from a naturalistic study on 400 patients with a schizophrenic spectrum disorder and simulated data sets were used. While calculations concerning absolute score values and their differences are not affected, considerable problems arise in calculations of PC and related response criteria. Even significance levels of estimated treatment effects change, depending on the structure of the data (eg, baseline symptom severity). Using a PANSS version with items ranging from 0 to 6 would avoid such often neglected pitfalls.

Antipsychotic Response in the First Week Predicts Later Efficacy

“…The ROC curve is a graphical plot of sensitivity versus (1-specificity) and the AUC represents a measure of the overall discriminative power: a value of 0.5 for the AUC indicates no discriminative ability, while a value of 1.0 indicates a perfect power [14]. The percentage PANSS reduction at 1 week was used as a predictor and it was calculated using the formula P% = [(P0–P1)/P0] × 100, where P0 was PANSS score at baseline and P1 was PANSS score at 1 week of treatment [15,16,17]. According to the suggestions by Obermeier et al [15,17] and Leucht et al [16], PANSS scores were corrected by subtracting 30 points (the minimum value of PANSS scale) to every PANSS score before calculating percent changes.…”

“…The percentage PANSS reduction at 1 week was used as a predictor and it was calculated using the formula P% = [(P0–P1)/P0] × 100, where P0 was PANSS score at baseline and P1 was PANSS score at 1 week of treatment [15,16,17]. According to the suggestions by Obermeier et al [15,17] and Leucht et al [16], PANSS scores were corrected by subtracting 30 points (the minimum value of PANSS scale) to every PANSS score before calculating percent changes. Subsequent response was calculated at 3 weeks of treatment instead of 4 due to the high number of subjects exiting the study (56 patients) at the fourth week of the study and it was defined as follows: (1) poor response: <26% reduction in adjusted PANSS score at 3 weeks of treatment [18] and (2) good response: >51% reduction in adjusted PANSS score at 3 weeks of treatment [18].…”

Clinical experience and perspectives of using asenapine in stopping acute endogenous psychosis

“…Эффективность терапии сафрисом опре-делялась также по степени редукции суммарного балла PANSS на день оценки по сравнению со значениями в 0-й день. При оценке степени редукции психопатологических расстройств в процентах во избежание явного занижения величины терапевтического ответа мы исключали из рас-четов суммарной балльной оценки PANSS на всех этапах лечения градацию «1» (отсутствие симптома), заменяя ее значением «0» согласно рекомендованной рядом авторов [21] методологии статистической обработки результатов PANSS. Степень эффективности лечения оценивали в пя-ти градациях.…”

Early Antipsychotic Response Predictors in Schizophrenia: A Naturalistic Study

“…According to the suggestion by Obermeier et al [25] and Leucht et al [26], PANSS scores were corrected by subtracting 30 points (the minimum value of PANSS scale) to every PANSS score before calculating percent changes.…”