Factor analysis of the Zung Self-Rating Depression Scale in a large ambulatory oncology sample

Screening cancer patients for depression with self-report inventories prese nts clinical and methodological challenges. Many investigators separate "so matic" from "cognitive" symptoms when adapting such measures to oncology se ttings. However this practice has rarely been empirically validated through factor-analytic studies. The following study describes a factor analysis o f the Zung Self-Rating Depression Scale (ZSDS) from a large ambulatory samp le of cancer patients (N = 1,109). A four-factor solution emerged, consisti ng of a cognitive symptom factor; a manifest depressed mood factor, and two somatic factors (eating and non-eating related). These factors accounted f or 20% (cognitive), 13% (mood), 8% (non-eating), and 7% (eating) of the var iance on the Zung, respectively. The authors discuss the implications of th ese results as they pertain to screening cancer patients for depression.