Ketamine for Treatment-Resistant Depression: a New Advocate.

Current alternatives for the treatment of major depressive disorder lack efficacy and have a delayed onset of action. Recently, the glutamatergic neurotransmission system has been noted to play an important role in the pathophysiology of this disorder. Ever since the first report of the antidepressant effects of the N-methyl-D-aspartate receptor antagonist, ketamine, research has been redirected to novel therapeutic targets. With this rapidly growing evidence of a fast-acting antidepressant such as ketamine, as well as its efficacy in treatment-resistant cases of depression, off-label use has become popular in certain settings. In this article, the clinical antidepressant properties of ketamine in relation to the glutamate hypothesis of depression are discussed, to highlight the breakthrough of these findings in the development of novel therapeutic strategies and provide a clearer view of its benefits and potential harms.