Patients With Atypical Symptoms of Depression Respond Better to Lithium Augmentation Than Patients Without Atypical Symptoms

Introduction: Understanding the differences in treatment response between subtypes of major depressive disorder (MDD) may help to prevent lengthy trial-and-error processes by identifying effective treatment options. The aim of the study was to investigate the impact of atypical features of MDD (MDD-A) on the response to lithium augmentation (LA). Methods: In a multicenter prospective cohort study, response to LA was compared between patients with atypical symptoms of MDD (MDD-A, n = 24) versus patients without atypical symptoms (MDD-nA; n = 94) using a Cox regression analysis. Results: A total of 62.5% of patients with MDD-A and 36.2% of patients with MDD-nA responded to LA. Analysis adjusted for age, sex, sufficient lithium serum concentration, and symptom severity at baseline showed a significantly higher probability of patients with atypical symptoms to respond to LA (HR 2.20, p = 0.02). Conclusion: This is the first study investigating lithium-response in patients with MDD-A. The MDD-A subtype may help to predict response to LA. Trial Registration: EudraCT number: 2008-004182-26; ClinicalTrials.gov identifier: DRKS00026205.