Exploratory and confirmatory factor analytic investigations of the Illness Attitudes Scale in a nonclinical sample

Abstract

The Illness Attitudes Scale (IAS) assesses fears, beliefs and attitudes associated with hypochondriasis [Kellner, R. (1986). Somatization and hypochondriasis. New York: Praeger Publishers.]. Recent factor analytic investigations of the IAS in non-clinical samples have suggested a number of different factor solutions. In study 1, we used principal components analysis with both orthogonal and oblique rotation to better explore the structure of this measure. Using a random selection of 390 participants from a larger pool of 780, a five-factor solution was identified: (1) fear of illness, death, disease and pain, (2) effects of symptoms, (3) treatment experiences, (4) disease conviction and (5) health habits. In study 2, confirmatory factor analysis (CFA) of responses from the remaining 390 students evaluated: (a) a single-factor model, (b) Kellner's original nine-factor model, (c) a four-factor model proposed by Ferguson and Daniel [Ferguson, E. & Daniel, E. (1995). The Illness Attitudes Scale (IAS): a psychometric evaluation on a nonclinical population. Personality and Individual Differences, 18, 463-469.], (d) a different four-factor model proposed by Stewart and Watt [Stewart, S. H. & Watt, M. C. (1998). A psychometric investigation of the Illness Attitudes Scale (IAS) in a nonclinical young adult sample. Submitted for publication.] and (e) the five-factor model derived in study 1. Of these models, greatest support was obtained for our five-factor model. However, it was also clear that this model could be improved. Based on the results of the CFA, as well as previous research and theoretical considerations, we tested a revised model in which the health habits factor was deleted. Analysis of the revised model showed that it received the greatest support and could be conceptualized as either four distinct factors or as hierarchical in nature, with four lower-order factors loading on a single higher-order factor. Future directions for research as well as suggestions for scoring and using the IAS with nonclinical samples are discussed.