The Validation of the Revised Illness Perception Questionnaire in Cancer Patients: An Exploratory Factor Analysis for Further Psychometric Evidence.

OBJECTIVE

Applying the Leventhal's model would make it possible to highlight the cognitive and emotional representations of adults with cancer and then to propose specific interventions to improve their adherence. This paper was conducted aiming at the validation of the revised illness perception questionnaire (IPQ-R) based on an exploratory factor analysis (EFA) in cancer patients.

DESIGN

The IPQ-R was administered to 300 outpatients referred during a 9 months period. In the present study, we performed an EFA to examine the construct validity of the instrument. In addition, the concurrent validity of the IPQ-R with the positive and negative affect schedule, depression, anxiety and stress scale- 21 items and 36-item Short-Form Health Survey questionnaires was evaluated. Reliability was calculated using Cronbach's alpha, McDonald's omega, and test-retest methods.

RESULTS

EFA of the beliefs and causes subscales revealed seven dimensions and three factors, respectively. With the difference that in the causes subscale, instead of the four factors of the original study, three factors were extracted. The validity and reliability of the identity subscales and beliefs overall were rated as good to excellent, but the concurrent validity of the Causes subscale was in the factor of psychological attributions and risk factor high and low, respectively, and for the substance use factor, it also did not obtain any correlation. For reliability, the risk factors received a low score.

CONCLUSION

Adaptation of the IPQ-R in Iranian culture and an adult population suffering from cancer disease made it possible to use it for this particular population.