Ketamine has been shown to be efficacious for the treatment of depression, specifically among individuals who do not respond to first-line treatments. There is still, however, a lack of clarity surrounding the clinical features and response periods across samples that respond to ketamine. This paper systematically reviews published randomized controlled trials that investigate ketamine as an antidepressant intervention in both unipolar and bipolar depression to determine the specific clinical features of the samples across different efficacy periods. Moreover, similarities and differences in clinical characteristics associated with acute versus longer-term drug response are discussed. Similarities across all samples suggest that the population that responds to ketamine’s antidepressant effect has experienced chronic, long-term depression, approaching ketamine treatment as a “last resort”. Moreover, differences between these groups suggest future research to investigate the potential of stronger efficacy towards depression in the context of bipolar disorder compared to major depression, and in participants who undergo antidepressant washout before ketamine administration. From these findings, suggestions for the future direction of ketamine research for depression are formed.

氯胺酮已被证明对抑郁症有效，特别是对一线治疗无反应的人群。但是，对于氯胺酮有反应的样品，其临床特征和反应时间仍然缺乏明确性。本文系统地综述了已发表的随机对照试验，该试验研究了氯胺酮作为单相和双相抑郁的抗抑郁药物，以确定在不同疗效期内样品的具体临床特征。此外，讨论了急性和长期药物反应相关的临床特征的相似性和差异。所有样本的相似性均表明，对氯胺酮的抗抑郁作用有反应的人群经历了长期的长期抑郁症，将氯胺酮治疗作为“最后手段”。此外，这些人群之间的差异表明，未来的研究需要调查与躁郁症相比，在双相情感障碍的情况下以及在氯胺酮给药前接受抗抑郁药冲洗的受试者中，对抑郁症具有更强疗效的潜力。从这些发现中，形成了对氯胺酮用于抑郁症研究的未来方向的建议。