Psychometric evaluation of the Chicago Multiscale Depression Inventory in multiple sclerosis patients.

OBJECTIVE: The Chicago Multiscale Depression Inventory (CMDI), a comprehensive self-report measure of depression, has proven useful in the assessment of patients with chronic medical conditions. The objective of this study was to determine the validity of the CMDI in multiple sclerosis (MS) patients and explore the nature of depressive symptoms reported by people with MS.
METHOD: Using a combined classical and modern psychometric approach, the factor structure of responses in MS patients was compared with that of a normative sample to confirm meaningful subtypes of depression in MS (mood, depressive cognition, and vegetative symptoms). Patient groups also were compared by disease severity to evaluate differences in depression associated with differences in disease severity.
RESULTS: The results supported the factor structures of the measure, which was internally consistent, reliable, and factorially valid. Some items function differently in MS patients when compared with depressed patients and normals, offering a further opportunity to understand the unique clinical aspects of depression in people with MS compared with those without a concurrent physical illness.
CONCLUSIONS: Use of the CMDI to assess separate dimensions of depression may help to clarify the complex interrelationships among aspects of depression and health-related behavior.