Residual symptoms in depressed outpatients who respond by 50% but do not remit to antidepressant medication.

Little is known about the quantity or quality of residual depressive symptoms in patients with major depressive disorder (MDD) who have responded but not remitted with antidepressant treatment. This report describes the residual symptom domains and individual depressive symptoms in a large representative sample of outpatients with nonpsychotic MDD who responded without remitting after up to 12 weeks of citalopram treatment in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study. Response was defined as 50% or greater reduction in baseline 16-item Quick Inventory of Depressive Symptomatology--Self-Report (QIDS-SR₁₆) by treatment exit, and remission as a final QIDS-SR₁₆ of less than 6. Residual symptom domains and individual symptoms were based on the QIDS-SR₁₆ and classified as either persisting from baseline or emerging during treatment. Most responders who did not remit endorsed approximately 5 residual symptom domains and 6 to 7 residual depressive symptoms. The most common domains were insomnia (94.6%), sad mood (70.8%), and decreased concentration (69.6%). The most common individual symptoms were midnocturnal insomnia (79.0%), sad mood (70.8%), and decreased concentration/decision making (69.6%). The most common treatment-emergent symptoms were midnocturnal insomnia (51.4%) and decreased general interest (40.0%). The most common persistent symptoms were midnocturnal insomnia (81.6%), sad mood (70.8%), and decreased concentration/decision making (70.6%). Suicidal ideation was the least common treatment-emergent symptom (0.7%) and the least common persistent residual symptom (17.1%). These findings suggest that depressed outpatients who respond by 50% without remitting to citalopram treatment have a broad range of residual symptoms. Individualized treatments are warranted to specifically address each patient's residual depressive symptoms.