The association of electroconvulsive therapy to pharmacological treatment and its influence on cytokines.

Introduction: A growing body of evidence shows that disturbances in the immune system are involved in the pathogenesis of depression. Although the immune-modulating effects of antidepressants have been described, few studies have addressed the functioning of the immune system in relation to electroconvulsive therapy (ECT). This study aims to investigate if the addition of ECT to pharmacotherapy is associated with changes in cytokine levels.

Methods: Adult inpatients were invited to participate in this study on admission to a psychiatric unit. Those with a diagnosis of depression by Mini-International Neuropsychiatric Interview were included. At treatment discharge, patients were retrospectively divided into those who used combined ECT and pharmacotherapy (31 subjects) and those who used only pharmacotherapy (68 subjects). Pro-inflammatory cytokines IL-2, IL-6, TNF-α, IFN-γ, and IL-17, and anti-inflammatory IL-4 and Il-10, were measured in blood samples collected at admission and discharge. A generalized estimating equation model and the post hoc Bonferroni test were performed for statistical analysis.

Results: The combination of ECT with pharmacotherapy was associated with a decrease of IL-6 and an increase of TNF-α. Depressive inpatients, as a whole group, had a decrease of IL-6 and an increase of IFN-γ. No significant results were found for IL-2, IL-4, Il-10 and IL-17.

Conclusion: This study is clinically relevant because we highlight that, in agreement with the previous literature, IL-6 appears to be a useful marker in depression, and we show for the first time that its reduction is closely related to the use of ECT.