Should health anxiety be carved at the joint? A look at the health anxiety construct using factor mixture modeling in a non-clinical sample.

Cognitive-behavioral models conceptualize health anxiety as a construct that varies in degree along a continuum rather than existing as nonpathological versus pathological classes or taxons. Only two studies have empirically evaluated the latent structure of health anxiety, both using taxometric statistical methods and both supporting its conceptualization as continuous (Ferguson, 2009; Longley et al., 2010). We sought to further evaluate the latent structure of health anxiety using factor mixture modeling (FMM), which involved a combination of exploratory factor analysis (EFA) and mixture modeling that allowed comparison of models comprising one or more latent classes. Health anxiety symptom data were obtained from the Illness Attitude Scales (IAS) administered to 1768 university undergraduate students. Indicators of health anxiety, derived from EFA of IAS item data, included disease worry, disease conviction, health-related safety behaviors, fear of death, somatic focus, interference due to symptoms, and treatment seeking. FMM of these indicators suggested that health anxiety consists of two classes: (a) an "anxious" class comprising 81.4% of the sample and characterized primarily by somatic focus and interference due to symptoms, and (b) a "nonanxious" class comprising 18.6% of the sample with low scores on all indicators. Contrary to current conceptualizations and taxometric findings, the FMM results indicate the latent structure of health anxiety to be taxonic rather than continuous. Implications for the measurement and conceptualization of health anxiety are discussed and future research directions are highlighted.