To Örebro University

CFQ-CI was previously developed and preliminarily validated in a study with a single online-recruited inflammatory bowel disease (IBD) sample. The current study presents a further validation of CFQ-CI in four different samples of patients with chronic health conditions: a sample of 82 women with breast cancer, an online-recruited mixed sample of 100 people with cancer, a sample of 69 people with IBD, and an online-recruited mixed chronic illness sample of 93 participants. Confirmatory Factor Analyses, multi-group, reliability, and differences analyses were conducted.

Results indicated that the scale is a robust unidimensional 7-item measure of chronic illness-related cognitivefusion, with excellent reliability and structural validity across the four studied samples and in both paper-penciland online-based collection methods. Measurement invariance was not established across the samples, suggesting that CFQ-CI does not appear tofunction equivalently across different illness diagnoses.

This study confirms CFQ-CI as a robust, adequate, and simple measure of chronic illness-related cognitive fusion that can be used in different behavioural medicine research and clinical contexts. As the scale does not seem to present measurement invariance, comparing scores between different illness groups is not recommended.