Modulation of neuroimmune cytokine networks by antidepressants: implications in mood regulation

Major Depressive Disorder (MDD) is increasingly recognized as a neuroinflammatory condition characterized by dysregulated cytokine networks. This comprehensive review examines the immunomodulatory effects of antidepressant medications, revealing their significant impact on Th1/Th2 cytokine balance beyond their classical neurotransmitter actions. Clinical data show that diverse antidepressant classes consistently demonstrate immunomodulatory properties that extend beyond their classical neurotransmitter effects. These medications reduce pro-inflammatory markers (IFN-γ, TNF-α, IL-6) while enhancing anti-inflammatory cytokines (IL-10, TGF-β), effects particularly relevant for treatment-resistant cases with elevated baseline inflammation. The therapeutic potential of these immunoregulatory effects is supported by emerging interventions, including low-dose IL-2 immunotherapy, vagus nerve stimulation, and microbiota-targeted therapies, which show promise for specific depression subtypes. Importantly, these approaches appear most effective when guided by inflammatory biomarkers, suggesting a path toward personalized treatment strategies. By integrating findings from clinical studies and translational research, this work establishes immune modulation as a fundamental component of antidepressant action. The review provides a framework for developing next-generation treatments that target neuroimmune pathways in MDD, with particular emphasis on practical applications for treatment-resistant cases. These insights bridge the gap between neuropharmacology and clinical psychiatry, offering new therapeutic possibilities for patients with inflammation-associated depression.