Lateralized Hemispheric Mechanisms and the Antidepressant Effects of Right and Left Unilateral ECT

This article critically reviews the six controlled studies of the antidepressant effects of right unilateral versus left unilateral ECT (R-ECT, L-ECT), contrasting them with results recently obtained in double-blind, random assignment comparison of the two methods, using a square-wave stimulus, widely spaced temporoparietal electrode placement, and markedly supra-threshold stimulus charge. The author challenges the prevalent belief in a therapeutic advantage of R-ECT versus L-ECT, proposing instead the contrary case for a therapeutic advantage of L-ECT, based on the interaction of a hypothesized interhemispheric seizure threshold difference and a maximally efficient method of stimulus delivery.