Comparing bilateral to unilateral electroconvulsive therapy in a randomized study with EEG monitoring.

In a double-blind study, 48 DSM-III depressed patients were randomly assigned to either the bilateral or nondominant unilateral electroconvulsive therapy (ECT) group. Seizure length was monitored by electroencephalography (EEG). When seizures were less than 25 s, ECT was immediately readministered. When length of seizure and pretreatment depression scores were controlled between the two groups, there were no differences in treatment effectiveness, as measured by the Hamilton Rating Scale for Depression and the Beck Depression Inventory, or in the number of treatments required. This was true after five ECT treatments as well as after completing all ECT treatments. Thus, when ECT is monitored via EEG to assure the presence of an adequate seizure, bilateral and nondominant unilateral placement yield equivalent responses. If ECT had not been readministered immediately following a missed seizure, unilateral patients would have had significantly more missed seizures. Significant difficulties in both short- and long-term memory were found 24 hours after the fifth ECT in bilateral but not in nondominant unilateral patients. No apparent memory loss could be documented in nondominant unilateral ECT.