A Hypothesis to Explain Divergent Findings Among Studies Comparing the Efficacy of Unilateral and Bilateral ECT in...

This article explains divergent reports on the relative efficacy of unilateral and bilateral electroconvulsive therapy (ECT) by hypothesizing a therapeutic effect of both seizure and electrical stimulus, with the seizure's effect based on its intensity and generalization. The effect of the stimulus is normally obscured by the seizure but emerges with reduced electrical dosage or elevated threshold. These circumstances favor a therapeutic advantage for bilateral ECT, which introduces more electrical charge into a larger and differently distributed volume of brain and induces greater seizure generalization, more diencephalic stimulation, and a relative decrease in left relative to right hemisphere electroencephalographic (EEG) frequencies.