Mood Disorders: Advances in Understanding Depression and Bipolar Disorder

This chapter provides a rigorous review of current scientific knowledge on the pathophysiology, course, and management of major depressive disorder and bipolar spectrum disorders. It addresses evolving neurobiological models, including the roles of neuroinflammation, circadian dysregulation, and reward circuitry dysfunction, and evaluates how these models are informing the development of new therapeutic targets. Special attention is given to treatment-resistant depression, the growing evidence base for rapid-acting antidepressants, and advances in the longitudinal characterization of bipolar disorder.