Changes in the Beck Depression Inventory-II's underlying symptom structure over 1 month of inpatient treatment

Research has not investigated changes in the symptom structure of depression over the course of mental health treatment. In the present study, 1025 psychiatric inpatients were recruited and assessed for depression symptom severity using the Beck Depression Inventory-II (BDI-II) at admission and after 1 month of treatment. A three-factor BDI-II model was tested using confirmatory factor analysis and fit reasonably well at both time points. Measurement invariance testing results demonstrated that factor loadings increased, indicating that the meaning of the three underlying depression dimensions changed through treatment. However, observed variable intercepts and residual error variances decreased significantly after 1 month of treatment, reflecting decreases in symptom severity as well as measurement error. Thus, depressive symptom severity decreased over the course of treatment, and the underlying factor structure of depression improved in fit after treatment. Implications for changes to the structure of depression symptoms and in the clinical practice of tracking depression over time are discussed.