Gamma-aminobutyric acid involvement in depressive illness: Interactions with corticotropin-releasing hormone and serotonin

There is little doubt that genetic and experiential factors contribute to the neurochemical processes responsible for the development of major depressive disorder (MDD) (Caspi et al., 2003; Kendler et al., 2005; Millan, 2006). In this regard, MDD is a biochemically heterogeneous disorder, and any of several neurochemical and/or receptor alterations provoked by stressful experiences might contribute to the development of depressive symptoms. Moreover, the effectiveness of antidepressants in attenuating MDD symptoms might be tied to the particular neurochemical alterations elicited by stressors in any given individual, and multitargeting as a strategy for the treatment of depression has received increased attention (Millan, 2006, 2009).