Assigning Clinical Significance and Symptom Severity Using the Zung Scales: Levels of Misclassification Arising from Confusion between Index and Raw Scores

Abstract

A large percentage of publications involving the Zung SDS and SAS scales are using incorrect criteria for the classification of clinically significant symptoms of depression and anxiety. The most common error-applying index score criteria to raw scores-produces a substantial elevation of the cut-off points for significance. Given the continuing usage of these scales, it is important that these inconsistencies be highlighted and resolved.