title: Efficacy of ketamine in the rapid treatment of major depressive disorder: a meta-analysis of randomized, double-blind, placebo-controlled studies.
abstract: BACKGROUND
  An increasing number of studies are reporting that ketamine could be treated as a novel antidepressant for major depressive disorder (MDD). Therefore, we performed this meta-analysis to comprehensively and systematically assess the efficacy of ketamine for treating patients with MDD.
  
  
  METHODS
  Randomized, double-blind, placebo-controlled studies on ketamine versus placebo for treating MDD were searched up to April 2016 in medical databases (PubMed, CCTR, Web of Science, Embase, CBM-disc, and CNKI). Three treatment time points (24 and 72 h, and day 7) were chosen. Response and remission rates were the main outcomes. The random effects model was used. An intention-to-treat analysis was conducted.
  
  
  RESULTS
  Nine high-quality studies that included 368 patients were selected to compare the efficacy of ketamine to placebo. The therapeutic effects of ketamine at 24 and 72 h, and day 7 were found to be significantly better than placebo. Response and remission rates in the ketamine group at 24 and 72 h, and day 7 were 52.2% and 20.6%; 47.9% and 23.8%; and 39.8% and 26.2%, respectively. No significant heterogeneity existed, and the Egger's test showed no publication bias.
  
  
  CONCLUSIONS
  These results indicated that ketamine could yield a good efficacy in the rapid treatment of MDD. Future large-scale clinical studies are needed to confirm our results and investigate the mid- and long-term efficacy of ketamine in treating MDD.
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Chongqing Medical University; Institute of Neuroscience and the Collaborative Innovation Center for Brain Science; Chongqing Key Laboratory of Neurobiology.
authors.forename: Yu
authors.initials: Y
authors.lastname: Han
authors.affiliation: Institute of Neuroscience and the Collaborative Innovation Center for Brain Science; Chongqing Key Laboratory of Neurobiology; Institute of Life Sciences, Chongqing Medical University, Chongqing, People's Republic of China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Chongqing Medical University; Institute of Neuroscience and the Collaborative Innovation Center for Brain Science; Chongqing Key Laboratory of Neurobiology.
authors.forename: Dezhi
authors.initials: D
authors.lastname: Zou
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Chongqing Medical University; Institute of Neuroscience and the Collaborative Innovation Center for Brain Science; Chongqing Key Laboratory of Neurobiology.
authors.forename: Peng
authors.initials: P
authors.lastname: Zheng
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Chongqing Medical University; Institute of Neuroscience and the Collaborative Innovation Center for Brain Science; Chongqing Key Laboratory of Neurobiology.
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Chongqing Medical University; Institute of Neuroscience and the Collaborative Innovation Center for Brain Science; Chongqing Key Laboratory of Neurobiology.
authors.forename: Haiyang
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Chongqing Medical University; Institute of Neuroscience and the Collaborative Innovation Center for Brain Science; Chongqing Key Laboratory of Neurobiology.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Chongqing Medical University; Institute of Neuroscience and the Collaborative Innovation Center for Brain Science; Chongqing Key Laboratory of Neurobiology.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Chongqing Medical University; Institute of Neuroscience and the Collaborative Innovation Center for Brain Science; Chongqing Key Laboratory of Neurobiology.
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Chongqing Medical University; Institute of Neuroscience and the Collaborative Innovation Center for Brain Science; Chongqing Key Laboratory of Neurobiology.
authors.forename: Yiyun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Chongqing Medical University; Institute of Neuroscience and the Collaborative Innovation Center for Brain Science; Chongqing Key Laboratory of Neurobiology.
authors.forename: Peng
authors.initials: P
authors.lastname: Xie
keywords: MDD; ketamine; major depressive disorder; meta-analysis