The Norwegian versions of the Chronic Pain Acceptance Questionnaire CPAQ-20 and CPAQ-8 - validation and reliability studies.

Purpose: The aim of this study was to test the validity and reliability of the translated Norwegian version of the Chronic Pain Acceptance Questionnaire (CPAQ-20) and the shorter version CPAQ-8 based on the same data.

Method: The sample consisted of 120 women with chronic widespread musculoskeletal pain (CWP). The respondents completed CPAQ-20 and visual analogue scales (pain, fatigue, sleep problems and depression), General Health Questionnaire-12, The Pain Catastrophizing Scale, Fibromyalgia Impact Questionnaire and SF-8. Confirmatory factor analyses were performed on a one-factor baseline model, the previous validated CPAQ-20 and CPAQ-8 models, as well as an exploratory generated model based on the current sample.

Results: The two-factor model of CPAQ-20 and a two-factor model of CPAQ-8 obtained adequate model fit and outperformed the baseline model. The exploratory factor, analysis-generated two-factor model obtained only a marginally better fit, supporting the two-dimensional model of CPAQ-20. CPAQ-20 and CPAQ-8 had Cronbach's alphas between 0.75 (Pain Willingness subscales both versions) and 0.85. Both scales correlated significantly in the hypothesised direction with all the other scales.

Conclusion: The Norwegian versions of CPAQ-20 and CPAQ-8 are reliable assessment tools with good construct validity for measurement of acceptance. Future studies should validate the scales in other Norwegian samples. Implication for Rehabilitation CPAQ-20 and CPAQ-8 are valid Norwegian instruments for measuring acceptance of pain. Acceptance of pain is an important process in the rehabilitation of persons with chronic widespread pain. Treatment models supporting acceptance can now be developed and measured further in Norway.