Figure 1. Flow chart of the literature search. The search was made with the terms “olanzapine”, “aripiprazole”, “risperidone”, “quetiapine”, “major depressive disorder”, and “randomized controlled trial”. EMBASE and other related databases were also searched with the same items produced through PubMed. CCRCT: Cochrane Central Register of Controlled Trials (to July 2012); DARE: Database of Abstracts of Reviews of Effects; MDD: major depression disorder.