Objective: The Hospital Anxiety and Depression Scale (HADS) is a prolifically used scale of anxiety and depression. The original bidimensional anxiety-depression latent structure of the HADS has come under significant scrutiny, with previous studies revealing one-, two-, three- and four-dimensional structures. The current study examines the latent structure of the HADS using a non-parametric item response theory method.
Method: Using data conglomerated from four independent studies of cardiovascular disease employing the HADS (n=893), Mokken scaling procedure was conducted to assess the latent structure of the HADS.
Results: A single scale consisting of 12 of 14 HADS items was revealed, indicating a unidimensional latent HADS structure.
Discussion: The HADS was initially intended to measure mutually exclusive levels of anxiety and depression; however, the current study indicates that a single dimension of general psychological distress is captured.
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