Abstract
Major depressive disorder (MDD) is a chronic, highly prevalent, and debilitating mental disorder associated with significant illness and economic burden globally. Exposure to trauma (eg, physical, sexual, emotional abuse, and/or physical, and emotional neglect) is common among individuals with MDD. Persons with MDD and a history of trauma often exhibit an attenuated response to conventional serotonergic antidepressants compared to those with non-traumatized depression. Emerging evidence indicates that exposure to trauma is associated with increased inflammatory markers [eg, C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α)] as well as glutamatergic dysregulation in the central nervous system (CNS). It is hypothesized that individuals with MDD and a history of trauma may be conceptualized as a distinct bio-phenotype compared to non-traumatized depression. Furthermore, preliminary evidence positions select glutamatergic modulators as potential, novel, mechanistically-informed therapeutic strategies that may provide benefit to persons with elevated inflammation and glutamatergic dysregulation.