In a visual analysis of electroencephalograms (EEGs) obtained in 33 melancholic men before and after six brief pulse right unilateral, left unilateral, or bilateral electroconvulsive therapy (ECT) treatments, the authors were unable to detect the relation between therapeutic outcome and differential hemispheric lateralization of ECT-induced EEG slowing that had been reported previously for sine wave ECT at the same clinical site. These results may be related to differences in neurophysiologic effects between sine wave and brief pulse ECT, and do not support the hypothesis that lateralization of ECT-induced EEG slowing is central to the antidepressant effects of ECT.