Do Antidepressants Exert Effects on the Immune System?

Abstract

The role of the immune system and interactions between the endocrine, neurotransmitter, and immune systems in affective disorders have opened up new avenues to pursue in psychiatric research. Exploration of a potential causal relationship between inflammation and depression has lent support to the contention that a bidirectional relationship is at play. Exogenously administered cytokines can induce a syndrome mimicking many symptoms of the spontaneously occurring syndrome of depression. The majority of clinical studies of depression, in which proinflammatory biomarkers were measured, confirmed that a chronic inflammatory status is present, as measured mostly in blood but also in cerebrospinal fluid and postmortem brain of suicide victims with a history of depression. However, it is unclear as to what happens to the pro-inflammatory status following symptom resolution and remission of the depressive episode. In this context the precise role antidepressant agents play in the resolution of inflammation and return of the immune system to homeostasis has been the object of numerous studies. This chapter seeks to provide a critical overview of the available evidence in the literature and address key factors that contribute to the discrepant findings. Specifically, select basic and clinical studies are discussed and recommendations are made how future studies can lead to greater consistency amongst reported findings. (PsycINFO Database Record (c) 2018 APA, all rights reserved)