Dimensionality of the hospital anxiety and depression scale (HADS) in cardiac patients: comparison of Mokken scale analysis and factor analysis.

The hospital anxiety and depression scale (HADS) measures anxiety and depressive symptoms and is widely used in clinical and nonclinical populations. However, there is some debate about the number of dimensions represented by the HADS. In a sample of 534 Dutch cardiac patients, this study examined (a) the dimensionality of the HADS using Mokken scale analysis and factor analysis and (b) the scale properties of the HADS. Mokken scale analysis and factor analysis suggested that three dimensions adequately capture the structure of the HADS. Of the three corresponding scales, two scales of five items each were found to be structurally sound and reliable. These scales covered the two key attributes of anxiety and (anhedonic) depression. The findings suggest that the HADS may be reduced to a 10-item questionnaire comprising two 5-item scales measuring anxiety and depressive symptoms.