The multidimensional inventory of hypochondriacal traits: factor structure, specificity, reliability, and validity in patients with hypochondriasis.

Severe health anxiety constitutes a disabling and costly clinical condition. The Multidimensional Inventory of Hypochondriacal Traits (MIHT) represents an innovative instrument that was developed according to cognitive-behavioral, cognitive-perceptual, interpersonal, and trait models of hypochondriasis. We aimed at evaluating the psychometric properties of the MIHT in a sample of patients with the Diagnostic and Statistical Manual of Mental Disorders (4th ed.) diagnosis of hypochondriasis. Using confirmatory factor analysis (CFA), the postulated four-factor structure of the MIHT was found in a first CFA in patients with hypochondriasis (n = 178) and in a second CFA based on a mixed sample, with other somatoform disorders (n = 27), panic disorder (n = 25), and healthy controls (n = 31) added to the original group of patients with hypochondriasis (n = 178). In terms of specificity, patients with hypochondriasis showed larger scores on all four MIHT subscales (i.e., affective, cognitive, behavioral, and perceptual) compared to all other groups. Analyses of convergent and discriminant validity revealed promising results concerning the MIHT affective and perceptual scales but also point to certain problematic issues concerning the MIHT cognitive and behavioral scales. The findings suggest that the proposed structure of the MIHT is valid also in patients with hypochondriasis and demonstrate the specificity of the four hypochondriacal traits assessed in the MIHT.