Hospital Anxiety and Depression Scale
Hospital Anxiety and Depression Scale (HADS) was originally developed by Zigmond and Snaith (1983) and is commonly used by doctors to determine the levels of anxiety and depression that a patient is experiencing. The HADS is a fourteen item scale that generates ordinal data. 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
- I feel tense or wound up
- I get a sort of frightened feeling as if something bad is about to happen
- Worrying thoughts go through my mind
- I can sit at ease and feel relaxed
- I get a sort of frightened feeling like butterflies in the stomach
- I feel restless and have to be on the move
- I get sudden feelings of panic
The items that relate to depression are
- I still enjoy the things I used to enjoy
- I can laugh and see the funny side of things
- I feel cheerful
- I feel as if I am slowed down
- I have lost interest in my appearance
- I look forward with enjoyment to things
- I can enjoy a good book or radio or TV programme
Scoring the questionnaire
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. The scale used is a Likert scale and therefore the data returned from the HADS is ordinal.
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 (2002) through a systematic review of a large number of studies identified a cut-off point of 8/21 for anxiety or depression. For anxiety (HADS-A) this gave a specificity of 0.78 and a sensitivity of 0.9. For depression (HADS-D) this gave a specificity of 0.79 and a sensitivity of 0.83.
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.
- Zigmond, AS; Snaith, RP (1983). "The hospital anxiety and depression scale". Acta Psychiatrica Scandinavica 67 (6): 361–370. PMID 6880820.
- Bjelland, I; et al (2002). "The validity of the Hospital Anxiety and Depression Scale. An updated literature review". Journal of Psychosomatic Research 52 (2): 69–77. PMID 11832252.