Advancing the assessment of psychological flexibility: development and validation of a novel context-sensitive measure in people with chronic physical illness

The current study aimed to develop and validate a novel context-sensitive measure of chronic illness-related psychological flexibility: the Psy-Flex-CI. Its factor structure and psychometric properties were explored in a sample of 286 Portuguese adults who received at least one diagnosis of chronic physical illness. Results confirmed the plausibility of the single-factor structure of the Psy-Flex-CI, with very good fit indices. Also, findings supported the Psy-Flex-CI's reliability. Support for convergent validity was also found with significant correlations between the Psy-Flex- CI and other measures of interest (psychological flexibility and inflexibility, body functionality appreciation, psychopathological symptoms) in the expected directions. Additionally, the Psy-Flex-CI showed incremental validity over a multidimensional measure of psychological flexibility (MPFI-24). Overall, our findings suggest that the Psy-Flex-CI is a reliable and valid measure to assess chronic illness-related psychological flexibility in individuals diagnosed with chronic physical illness. The development of the Psy-Flex-CI may thus be a useful contribution for the chronic illness field, in both clinical and research contexts.