Background: The Illness Cognition Questionnaire (ICQ; Evers et al., J Consult Clin Psychol, 69:1026-1036, 2001) assesses three ways of cognitively evaluating the stressful and aversive character of a chronic illness: helplessness, acceptance, and perceived benefits.
Purpose: The purpose of this study was to evaluate the construct validity of the ICQ in individuals with chronic pain and patients with chronic fatigue.
Method: The ICQ was administered to 821 individuals with chronic pain and 295 patients with chronic fatigue. Confirmatory factor analyses were performed to assess the hypothesized three-factor structure, containing the factors "helplessness," "acceptance," and "perceived benefits." A multigroup analysis was performed to investigate the stability of the factor structure in both groups.
Results: Results confirmed the three-factor structure in the two samples. The factor structure was invariant across individuals with chronic pain and chronic fatigue.
Conclusion: As the three-factor structure provided a good fit in both groups, we confirm the usefulness of the subscale scores in research and clinical practice.