Response of depressed patients to sequential unilateral nondominant brief-pulse and bilateral sinusoidal ECT.

Of 37 endogenously depressed patients given a course of unilateral nondominant brief-pulse ECT, 20 responded well and received no further treatment; 17 showed minimal clinical improvement but improved significantly after a subsequent course of bilateral sinusoidal ECT. These findings suggest that there may be subgroups of depressed patients who respond differentially to unilateral and bilateral ECT, to high- and low-energy stimuli, or to combinations thereof. Seizure duration did not appear to be a crucial variable in the efficacy of ECT; among the unilateral nonresponders, seizures of equal duration induced by unilateral stimulation were not as therapeutically effective as those induced by bilateral ECT. Response to the first three ECTs appeared to be the only predictor of unilateral responsiveness.