Depression represents the number one cause of disability worldwide and is often fatal. Inflammatory processes have been implicated in the pathophysiology of depression. It is now well established that dysregulation of both the innate and adaptive immune systems occur in depressed patients and hinder favorable prognosis, including antidepressant responses. In this review, we describe how the immune system regulates mood and the potential causes of the dysregulated inflammatory responses in depressed patients. However, the proportion of never-treated major depressive disorder (MDD) patients who exhibit inflammation remains to be clarified, as the heterogeneity in inflammation findings may stem in part from examining MDD patients with varied interventions. Inflammation is likely a critical disease modifier, promoting susceptibility to depression. Controlling inflammation might provide an overall therapeutic benefit, regardless of whether it is secondary to early life trauma, a more acute stress response, microbiome alterations, a genetic diathesis, or a combination of these and other factors.

抑郁症是全世界致残的第一大原因，并且通常是致命的。炎症过程与抑郁症的病理生理有关。现已公认，抑郁症患者会发生先天性和适应性免疫系统的失调，并阻碍包括抗抑郁反应在内的良好预后。在这篇综述中，我们描述了免疫系统如何调节抑郁症患者的情绪以及炎症反应失调的潜在原因。然而，由于炎症发现的异质性可能部分源于采用不同干预措施检查MDD患者，因此从未治疗的重度抑郁症（MDD）患者出现炎症的比例仍有待澄清。炎症可能是关键的疾病调节剂，可促进抑郁症的易感性。