Influence of pain & disability on individual HADS item responses
Research type
Research Study
Full title
Exploration of potential criterion contamination for items of the Hospital Anxiety and Depression Scale within a chronic pain population
IRAS ID
126858
Contact name
Martin Dunbar
Contact email
Sponsor organisation
NHS Greater Glasgow and Clyde
Research summary
Despite it’s widespread use in both clinical and research settings, the underlying factor structure of the Hospital Anxiety and Depression Scale (HADS) remains unclear. In addition, research evidence and clinical observations have raised questions over the construct validity of the HADS in terms of differential item functioning (criterion contamination). Despite being explicitly designed to be used within physically ill populations, there has been suggestion that response variance to certain items may be systematically influenced by somatic symptoms associated with physical health conditions.
Although there has been some investigation of this within other physical health conditions, very little work has been carried out within pain populations. This study will explore potential criterion contamination of HADS items within a sample of chronic pain patients, using a multi-method approach.Three sources of data will be used to generate hypotheses about which HADS items may be affected by criterion contamination. Firstly, existing scientific literature will be reviewed. Secondly, a small number of psychologists who specialise in pain will be asked to rate each item as to how likely it is to be influenced by the pain condition. Finally, a cognitive interviewing approach will elucidate the process by which chronic pain patients arrive at an answer to each item, and therefore reveal potential bias from somatic symptoms.
Once hypotheses have been generated from these sources, the second stage of the research will test them using existing HADS data, collected routinely as an outcome measure of the Glasgow Pain Management Programme (PMP). Two approaches will be used - Rasch Analysis and Confirmatory Factor Analysis.
This research will contribute important information to evaluate the construct validity of the HADS within chronic pain populations. It may be used to inform future discussion of potential item modifications and/or modified clinical cut off points.
REC name
London - Camberwell St Giles Research Ethics Committee
REC reference
13/LO/1411
Date of REC Opinion
30 Aug 2013
REC opinion
Favourable Opinion