A Randomized Comparison of High-Charge Right Unilateral Electroconvulsive Therapy and Bilateral Electroconvulsive Therapy in Older Depressed Patients Who Failed to Respond to 5 to 8 Moderate-Charge Right Unilateral Treatments

Background: Electroconvulsive therapy (ECT) is the treatment of choice in some older patients with severe depression. When compared with younger depressed patients, older patients have been shown to be as likely to respond to ECT but more likely to develop cognitive impairment. This study addresses whether adults aged 50 years and over who have already failed to respond to at least 5 moderate-charge right unilateral (RUL) ECT treatments (150% above seizure threshold) are more likely to benefit from a switch to high-charge RUL ECT (450% above threshold) or to bilateral (BL) ECT.

Method: Twenty-four patients who were treated with 5 to 8 moderate-charge RUL ECT treatments and who failed to improve sufficiently were randomly assigned to receive either BL ECT (N=11) or high-charge RUL ECT (N=13). Depressive (24-item Hamilton Rating Scale for Depression) and cognitive scores (Mini-Mental State Examination [MMSE]) were compared under double-blind conditions at 3 phases of treatment.

Results: Patients in the BL ECT group exhibited significantly greater cognitive impairment (mean MMSE score decrease of 1.13) than those receiving high-charge RUL ECT (mean MMSE increase of 1.71). There were no statistically significant differences in clinical response to BL or high-charge RUL ECT (63.6% and 61.5%, respectively) or in depressive symptom remission (18.1% and 46.2%).

Conclusion: These results suggest that older patients who fail to respond to moderate-charge RUL ECT may benefit from a switch to high-charge RUL ECT rather than BL ECT. Larger future studies will be needed to compare clinical response in patients switched from moderate-dose RUL ECT to higher-dose RUL or to BL ECT.