Evaluating latent variable models of functional somatic distress in a community-based sample

Abstract

This study evaluated the diagnostic validity of conditions that have been labeled functional somatic syndromes. In an effort to replicate prior work in this area, latent variable models of functional somatic distress were estimated from the responses of 213 community members to a medical questionnaire. Medical questionnaire items that closely conformed to formal diagnostic criteria for the conditions were used in model estimation. Results of confirmatory factor analysis supported diagnostic distinctions between five syndromes (fibromyalgia, chronic fatigue syndrome, somatic depression, somatic anxiety, and irritable bowel syndrome). Discrete diagnostic categories of fibromyalgia and chronic fatigue syndrome were then tested using logistic regression analysis, in which the outcome involved independent diagnosis of these conditions based upon physician evaluation. Evidence for the existence of discrete diagnoses of fibromyalgia and chronic fatigue syndrome was particularly strong, since these diagnoses were cross-validated using findings from physician evaluation tailored to diagnose these conditions. Findings can assist mental health practitioners in drawing theoretical and symptom-based distinctions between different types of syndromes characterized by physical complaints.