Initial Severity Effects on Residual Symptoms in Response and Remission: A STAR∗D Study during and after Failed Citalopram Treatment

The effects of initial severity on the time to and course of residual symptoms based on response or remission periods, and during and after failed response to citalopram in major depressive disorder are unknown. STAR∗D data during and after failed citalopram treatment were reanalyzed to examine the effect of initial severity on the time to and course of residual symptoms using the Quick Inventory of Depressive Symptomatology-Self-Report (QIDS-SR). During and after failed citalopram treatment, Cox regression and Generalized Estimating Equation models were computed to examine mild and moderate residual symptoms during (1) response based on at least a 50% QIDS-SR reduction, as well as (2) remission based on a QIDS-SR score below 6. Generally, initial severity significantly (P < 0.05) increased the time to and course of residual symptoms at the time of response and remission. The course of select mild and moderate residual symptoms was significantly (P < 0.05) more likely to persist in the presence of initial severity during response than remission (eg, energy) across treatment levels. It is concluded that initial severity is a predictor of the time to and course of residual symptoms. The presence of residual symptoms is more likely during response than remission, thereby directing their definition as a treatment target.