An investigation of amino-acid neurotransmitters as potential predictors of clinical improvement to ketamine in depression.

Amino-acid neurotransmitter system dysfunction plays a major role in the pathophysiology of major depressive disorder (MDD). We used proton magnetic resonance spectroscopy (¹H-MRS) to investigate whether prefrontal levels of amino-acid neurotransmitters predict antidepressant response to a single intravenous infusion of the N-methyl-D-aspartate (NMDA) antagonist ketamine in MDD patients. Fourteen drug-free patients with MDD were scanned 1-3 d before receiving a single intravenous infusion of ketamine (0.

Targeting glutamatergic signaling for the development of novel therapeutics for mood disorders.

There have been no recent advances in drug development for mood disorders in terms of identifying drug targets that are mechanistically distinct from existing ones. As a result, existing antidepressants are based on decades-old notions of which targets are relevant to the mechanisms of antidepressant action. Low rates of remission, a delay of onset of therapeutic effects, continual residual depressive symptoms, relapses, and poor quality of life are unfortunately common in patients with mood disorders.