Hospital Anxiety and Depression Scale


Hospital Anxiety and Depression Scale was originally developed by Zigmond and Snaith and is commonly used by doctors to determine the levels of anxiety and depression that a person is experiencing. The HADS is a fourteen item scale that generates: Seven of the items relate to anxiety and seven relate to depression. Zigmond and Snaith created this outcome measure specifically to avoid reliance on aspects of these conditions that are also common somatic symptoms of illness, for example fatigue and insomnia or hypersomnia. This, it was hoped, would create a tool for the detection of anxiety and depression in people with physical health problems.

Items on the questionnaire

The items on the questionnaire that relate to anxiety are
The items that relate to depression are:
Each item on the questionnaire is scored from 0-3 and this means that a person can score between 0 and 21 for either anxiety or depression.

Caseness of anxiety and depression

A number of researchers have explored HADS data to establish the cut-off points for caseness of anxiety or depression. Bjelland et al through a literature review of a large number of studies identified a cut-off point of 8/21 for anxiety or depression. For anxiety this gave a specificity of 0.78 and a sensitivity of 0.9. For depression this gave a specificity of 0.79 and a sensitivity of 0.83

Factor structure

There are a large number of studies that have explored the underlying factor structure of the HADS. Many support the two-factor structure but there are others that suggest a three or four factor structure. Some argue that the tool is best used as a unidimensional measure of psychological distress.

Criticisms

The factor structure of the HADS has been questioned. The HADS has also been criticised for its overreliance on anhedonia as being the core symptom of depression, how single-item measures of depression may have the same predictive value as the HADS scale, as well as its use of British colloquial expressions which can be difficult to translate.