The Role of Dopamine in the Pathophysiology and Treatment of Major Depressive Disorder

Many of the studies exploring dopamine (DA) function in depression have produced inconsistent findings. Contributors to this inconsistency include the diagnostic heterogeneity of major depressive disorder (MDD); failure to control for age, bipolar disorder, and comorbid diagnoses; and variation in patient medication treatment status at the time of the study. Despite this variability, there is now a convergence of data from animal models, genetics, neuroimaging, and human clinical trials that strengthens the case for DA dysfunction in the pathophysiology of major depression, at least in a significant subgroup of patients. This chapter comprehensively reviews the current evidence, with subsequent recommendations for future studies of dopaminergic signaling in depression and its treatment.