Neural and genetic correlates of cognitive deficits in major depressive disorder

Major depressive disorder (MDD) is characterized by affective symptoms including persistent low mood, loss of pleasure (anhedonia), and emotional dysregulation. Patients with MDD also exhibit a range of cognitive impairments whose behavioral characteristics and neural bases are still poorly understood. In this chapter, we will review the most commonly accepted neurobiological theories of MDD, linking these theories to the functional roles of the basal ganglia and hippocampus in mediating cognition. Finally, we will summarize the cognitive effects of naturally occurring genetic polymorphisms in dopamine and serotonin transporters in MDD. In each section, we will discuss critical gaps in the literature and potential ways to address them.