Evidence for GABAergic inhibitory deficits in major depressive disorder

Converging evidence suggests that deficits in gamma-aminobutyric acid (GABA) functioning are implicated in the pathophysiology of major depressive disorder (MDD). This is highlighted by research investigating cortical inhibition (Cl), a process whereby GABAergic interneurons selectively attenuate pyramidal neurons. Transcranial magnetic stimulation (TMS) paradigms evaluate this marker of neuronal inhibitory activity in the cortex. This review will examine the neuroanatomic and neurophysiological evidence from neuroimaging, molecular, treatment, and TMS studies linking dysfunctional GABAergic neurotransmission to MDD. (C) 2010 Elsevier Ltd. All rights reserved.