Abstract
Mood disorders such as depression are among the most prevalent psychiatric disorders in the United States, but they are inadequately treated in a substantial proportion of patients. Accordingly, neuropsychiatric research has pivoted from investigation of monoaminergic mechanisms to exploration of novel mediators, including the role of inflammatory processes. Subsets of mood disorder patients exhibit immune-related abnormalities, including elevated levels of proinflammatory cytokines, monocytes, and neutrophils in the peripheral circulation; dysregulation of neuroglia and blood-brain barrier function; and disruption of gut microbiota. The field of psychoneuroimmunology is one of great therapeutic opportunity, yielding experimental therapeutics for mood disorders, such as peripheral cytokine targeting antibodies, microglia and astrocyte targeting therapies, and probiotic treatments for gut dysbiosis, and producing findings that identify therapeutic targets for future development.