What Can We Tell About the Effect of Electroconvulsive Therapy on the Human Hippocampus?

Abstract

Electroconvulsive therapy (ECT) is the most effective antidepressant treatment, although its mechanisms of action remain unclear. Since 2010, several structural magnetic resonance imaging studies based on a neuroplastic hypothesis have consistently reported increases in the hippocampal volume following ECT. Moreover, volume increases in the human dentate gyrus, where neurogenesis occurs, have also been reported. These results are in line with the preclinical findings of ECT-induced neuroplastic changes, including neurogenesis, gliogenesis, synaptogenesis, and angiogenesis, in rodents and nonhuman primates. Despite this robust evidence of an effect of ECT on hippocampal plasticity, the clinical relevance of these human hippocampal changes continues to be questioned. This narrative review summarizes recent findings regarding ECT-induced hippocampal volume changes. Furthermore, this review also discusses methodological considerations and future directions in this field.

Introduction of the Special Issue on “Neurophysiology/Neuroimaging Study in Japan”

“…In a narrative review by Takamiya et al, 4 the authors overviewed recent findings on electro-convulsive therapy (ECT)-induced hippocampal volume changes, noting a possible neural basis for associations between hippocampal volume and neurogenesis after ECT. Further methodological considerations and future directions are discussed, since findings are inconsistent and mixed.…”