Electroconvulsive Therapy Decreases Dopamine D₂ Receptor Binding in the Anterior Cingulate in Patients With Depression: A Controlled Study Using Positron Emission Tomography With Radioligand [¹¹C]FLB 457

Abstract

Objective: Electroconvulsive therapy (ECT) has been confirmed as one of the most effective treat ments in drug-resistant major depression. However, the mechanism of ECT is still poorly understood. Although several lines of studies have focused on its effect on dopamine neurotransmission, the effects of ECT on dopamine D₂ receptors in a living human brain have not been investigated. Using positron emission tomography (PET) scans with the radioligand [¹¹C]FLB 457, we aimed to evaluate the effect of ECT on extrastriatal D₂ receptor binding in medicated patients with major depressive disorder (MDD).

Method: Seven patients with a DSM-IV diagnosis of MDD underwent PET scans before and after a series of 6–7 treatments with bilateral ECT. Eleven healthy controls were scanned for comparison. All participants were scanned at the National Institute
of Radiological Sciences, Chiba, Japan, between November 2000 and September 2005. The para metric images of [¹¹C]FLB 457 binding were generated on the basis of a simplified reference tissue model. Voxel-based methods were used to assess the effect of ECT on D₂ receptor binding.

Results: There were no significant differences in D₂ receptor binding between patients with MDD and controls. All 7 patients showed clinical improvements in response to ECT treatment (P < .001). Significant changes in D2 receptor binding, a mean of 25.2% reduction, were found in the right rostral anterior cingulate (AC) following ECT (P < .001).

Conclusions: Electroconvulsive therapy decreased D₂ receptor binding in the rostral AC in MDD patients responding to ECT. Our finding suggests that one of the biologic mechanisms of ECT could be related to dopaminergic alteration in the rostral AC.

J Clin Psychiatry 2010;71(6):793–799

© Copyright 2009 Physicians Postgraduate Press, Inc.

Submitted: September 27, 2008; accepted January 30, 2009.
Online ahead of print: December 15, 2009 (doi:10.4088/JCP.08m04746blu).
Corresponding author: Tetsuya Suhara, MD, PhD, Department of Molecular Neuroimaging, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba, 263-8555, Japan (suhara@nirs.go.jp)