Objective: the hospital anxiety and depression scale (HADS) attempts to measure anxiety and depression without confounding by somatic symptoms of physical disorder, and is widely used for this purpose. This paper addresses three questions about the validity of the HADS concerning its independence of physical symptoms, the extent to which its items robustly measure the identified constructs with varying clinical populations and situations, and its capacity to differentiate anxiety and depression.
Methods: data from patients with breast disease, myocardial infarction (MI), and stroke were examined using factor analytic and psychometric analyses.
Results: using exploratory factor analysis in patients with breast disease, 13 of the 14 HADS items fell on a psychological factor and loadings on the psychological factor were higher than loadings on the somatic factor for all items. The HADS showed high levels of internal consistency and there was little evidence that removing items would improve it. Confirmatory factor analyses (CFA) in MI and stroke groups confirmed the separation of anxiety and depression. Analyses indicated items, which were performing poorly for these clinical groups.
Conclusions: there was support for the validity of the HADS for all three questions. However, there were some evidences of individual items performing poorly. Given the ease of administration and the acceptability of this measure to ill or weak respondents, the HADS continues to perform satisfactorily.