Background: It remains unclear regarding the contribution of each individual symptom in predicting the outcome in major depressive disorder (MDD). The objective of this analysis was to evaluate trajectories of individual symptoms over time to identify which specific depressive item(s) could predict subsequent clinical response.
Methods: The data of 2874 outpatients with nonpsychotic MDD who received citalopram for up to 14 weeks in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) trial were analyzed. Average trajectories of individual symptoms over time were estimated for remitters and non-remitters. Moreover, specific symptoms whose improvement at week 2 predicted remission were identified, using binary logistic regression analysis.
Results: Trajectories were significantly different between remitters and non-remitters in all depressive symptoms. All depressive symptoms in the 16-item Quick Inventory of Depressive Symptomatology, Self-Report (QIDS-SR16) in the two groups, except for hypersomnia and weight change in non-remitters, substantially improved within 2 weeks and gradually continued to improve thereafter throughout the 14 weeks. Early improvements in the following five symptoms, in order of magnitude, in the QIDS-SR16 were significantly associated with remission: sad mood, negative self-view, feeling slowed down, low energy, and restlessness (P<0.001, P<0.001, P=0.001, P=0.004, P=0.021).
Limitations: The participants were limited to the nonpsychotic MDD outpatients who received citalopram. Further, symptomatology was not evaluated at the very beginning of treatment.
Conclusions: While the data pertain to citalopram and replication is necessary for other antidepressants, early improvements in certain core depressive symptoms may serve as a predictor of subsequent remission.
Trial registration: ClinicalTrials.gov NCT00021528.
Keywords: Depression; Major depressive disorder; Prediction; Remission.
© 2013 Elsevier B.V. All rights reserved.