ABSTRACT
Major depressive disorder (MDD) is a serious and complex mental illness. Currently, many antidepressants are available in the market for the treatment of MDD. However, these agents are associated with side effects, which restricts their use. This warrants the development of advanced antidepressive medications with a novel mechanism of action or novel targets and with minimal adverse effects. The traditional neurobiological hypothesis of depression, the monoamine hypothesis, is unable to properly explain all the aspects of depressive conditions. In this review, we discuss novel approaches that could be used for the treatment of depression, including glutamatergic and serotonergic system modulation. The pathogenesis of depression is greatly affected by glutamatergic neurotransmission dysfunction. Previous investigations have shown that ketamine, an N-methyl-D-aspartate receptor antagonist, exerts fast and long-lasting antidepressant effects. Several glutamatergic modulators, such as esketamine, sarcosine, and others, have also shown potential antidepressant action in animal as well as clinical studies. Lastly, drugs that alter neurotransmission by NMDA receptors could open up new avenues for more effective treatment of depression. Besides, understanding the underlying mechanisms will aid in the development of novel and fast-acting antidepressant drugs in the future.
