Introduction: Depression and Its Subtypes: A Treatment Update

Despite the considerable advance in recent years in our understanding of the course and treatment of major depressive disorder, psychiatry remains challenged by significant gaps in our understanding of the etiology of the disorder and in the adequacy of our therapeutics. Although the minority of patients seeking treatment for major depression will be refractory, the majority, despite our treatment efforts, will endure residual symptoms, continued impairment, and recurrences. For a disorder with the adverse social and health impact of major depression and a lifetime prevalence of about 15% of the population, the motivation to do better is compelling.