Improvement of psychomotor retardation after electroconvulsive therapy is related to decreased IL-6 levels

Prior studies suggest that IL-6 may be involved in the pathophysiology of psychomotor symptoms in depression. Electroconvulsive therapy (ECT), as yet the most effective biological treatment of severe depression, is known to improve psychomotor functioning, while recent studies have shown a decrease in the elevated IL-6 levels of depressed patients following ECT. This study investigates whether the improvement in psychomotor functions in patients with depression after ECT is related to changes in IL-6 levels. Peripheral IL-6 was quantified and the severity of psychomotor agitation and retardation determined using the CORE assessment of psychomotor symptoms in 62 patients with a (unipolar or bipolar) depressive episode within one week before and within one week after their course of ECT. IL-6 levels had decreased significantly following ECT and both psychomotor retardation and agitation had improved. The decrease in IL-6 levels was related to the improvement of psychomotor retardation, with post-hoc analysis revealing that higher baseline IL-6 levels positively correlated with higher psychomotor retardation scores. With this study, we provide the first evidence that the improvement of psychomotor retardation after ECT for depression is related to the immunomodulatory properties of the treatment, most specifically the decrease in IL-6 levels. •ECT improved psychomotor retardation.•IL-6 levels decreased significantly following ECT.•Decreased IL-6 levels were related to the improvement of psychomotor retardation.