Comparison of Unitary and Multidimensional Models of the Whiteley Index in a Nonclinical Sample: Implications for Understanding and Assessing Health Anxiety

Health anxiety is an important but poorly assessed phenomenon. Manifesting along a continuum, health anxiety is the result of a catastrophic appraisal of somatic sensations and changes as indicative of disease. The Whiteley Index (WI) is one of the most widely used self-report measures for assessing health anxiety both for research and for clinical practice. It generally exhibits excellent and robust psychometric properties for internal consistency, test-retest reliability, convergent validity, and concurrent validity; however, both its item content and its factor structure are matters of debate. Moreover, the measure has rarely been assessed in nonclinical samples. For the present study, a sample of 300 participants from the University of Regina completed the WI. If the latent dimensions identified in factor analysis represent etiologic mechanisms, then the elucidation of the WI's factor structure may enhance our understanding of health anxiety. Exploratory factor analysis was used to determine a robust and reliable item content and factor structure, resulting in a six-item two-factor structure that was invariant across gender. The two factors were denoted Somatic Symptoms/Bodily Preoccupation and Disease Worry/Phobia. Previous factor structure solutions were compared to the factor structure derived from this study by means of confirmatory factor analysis. The newly established item content and factor structure resulted in acceptable fit indices that were statistically superior to those found using the previous factor structure solutions. Implications and directions for assessment of health anxiety and future research are discussed.