Factor analysis of the Revised Illness Perception Questionnaire in adults with atopic dermatitis

The objective of this study was to examine the psychometric properties of the revised Illness Perceptions Questionnaire (IPQ-R) in adult participants with atopic dermatitis (AD). Two hundred and eighty-four participants who had a GP or dermatologist confirmed diagnosis of AD completed the IPQ-R. The factor structure of the IPQ-R was examined using confirmatory (CFA) and exploratory factor analysis (EFA). The results of the CFA did not indicate a good comparative fit with the IPQ-R subscales, while the EFA and a fixed six-factor principal components analysis largely replicated the original factor structure of the IPQ-R. The existence of the acute/chronic and cyclical timeline dimensions, and the illness coherence subscale was most strongly supported, while all items of the consequences and emotional representation subscales consistently loaded onto one factor. The EFA for causal attributions did not produce a stable solution. The findings indicate that although the factor structure of the IPQ-R was not confirmed in the sample of patients with AD using CFA, it was partly reproduced using EFA. Overall, the results suggest that in patients with AD the IPQ-R, in particular the consequences and emotional representations subscales, should be employed and interpreted with care.