Exploratory Factor Analysis of the Beck Anxiety Inventory and the Beck Depression Inventory-II in a Psychiatric Outpatient Population

Abstract

Background: To further understand the relationship between anxiety and depression, this study examined the factor structure of the combined items from two validated measures for anxiety and depression. Methods: The participants were 406 patients with mixed psychiatric diagnoses including anxiety and depressive disorders from a psychiatric outpatient unit at a university-affiliated medical center. Responses of the Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI)-II, and Symptom Checklist-90-Revised (SCL-90-R) were analyzed. We conducted an exploratory factor analysis of 42 items from the BAI and BDI-II. Correlational analyses were performed between subscale scores of the SCL-90-R and factors derived from the factor analysis. Scores of individual items of the BAI and BDI-II were also compared between groups of anxiety disorder (n = 185) and depressive disorder (n = 123). Results: Exploratory factor analysis revealed the following five factors explaining 56.2% of the total variance: somatic anxiety (factor 1), cognitive depression (factor 2), somatic depression (factor 3), subjective anxiety (factor 4), and autonomic anxiety (factor 5). The depression group had significantly higher scores for 12 items on the BDI while the anxiety group demonstrated higher scores for six items on the BAI. Conclusion: Our results suggest that anxiety and depressive symptoms as measured by the BAI and BDI-II can be empirically differentiated and that particularly items of the cognitive domain in depression and those of physical domain in anxiety are noteworthy.