Abstract:
OBJECTIVE: Symptoms of chronic fatigue syndrome (CFS) can be perpetuated by cognitive and behavioural responses to the illness. We aimed to determine the factor structure, reliability and validity of the 40-item Cognitive Behavioural Responses Questionnaire (CBRQ) using data gathered from CFS patients. We also propose a short version CBRQ for greater clinical utility.
METHODS: The psychometric analysis was performed on datasets drawn from two sources: a clinical service for CFS patients (N=576) and the PACE randomised controlled trial (RCT) of CFS treatments (N=640). An exploratory factor analysis (EFA) was conducted on the clinical dataset and a confirmatory factor analysis (CFA) was performed on the RCT dataset. Using these results, a short version of the CBRQ was proposed. Reliability, metric invariance across age and sex, and construct validity were assessed.
RESULTS: The EFA (relative Chi-square 2.52; RMSEA 0.051; CFI 0.964; TLI 0.942) and CFA (relative Chi-square 4.029; RMSEA 0.069; CFI 0.901; TLI 0.892) revealed that eight factor models fitted the data well. Satisfactory Cronbach’s alpha values were obtained for the final subscales (≥0.76). The shortened CBRQ was obtained by removing items that cross-loaded onto other factors and/or were the lowest loading items in each factor. The shortened CBRQ contained 18 items which had high factor loadings, good face-validity and reliability (Cronbach’s alpha 0.67-0.88).
CONCLUSIONS: The CBRQ, long and short versions, are reliable and valid scales for measuring cognitive and behavioural responses of patients with CFS. Further research is needed to examine the utility of the CBRQ in other long-term conditions.
Source: Ryan EG, Vitoratou S, Goldsmith KA, Chalder T. Psychometric properties and factor structure of a shortened version of the Cognitive Behavioural Responses Questionnaire (CBRQ). Psychosom Med. 2017 Oct 10. doi: 10.1097/PSY.0000000000000536. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/29023262