Speed of electroconvulsive therapy for depression: Effects of electrode placement

Electroconvulsive therapy (ECT) is a rapidly effective treatment for severe depression. Treatment with right unilateral (RUL) or bitemporal (BT) ECT may explain individual differences in speed of ECT effectiveness. There is limited evidence for demographic and clinical factors that predict speed of response and remission with ECT. We aimed to investigate differences in speed of improvement as well as achieving response and remission between twice-weekly brief-pulse high-dose (6 × seizure threshold) RUL ECT and moderate-dose (1.5 × seizure threshold) BT ECT. We also explored demographic and clinical characteristics that predict speed of response and remission.

Weekly 24-item Hamilton Depression Rating Scale scores were assessed among patients with severe depression who participated in the EFFECT-Dep trial (ISRCTN23577151). Speed of improvement in patients randomised to RUL ECT (n = 69) or BT ECT (n = 69) was compared using independent sample t tests. Pearson's chi-square and Fisher's exact tests compared proportions of responders and remitters at each weekly assessment. Predictors of speed of response and remission were explored using Cox regression analyses.

There were no significant differences between RUL and BT ECT in speed of improvement, response or remission. Exploratory analyses indicated that speed of response and remission were not predicted by a wide variety of demographic and clinical characteristics.

ECT electrode placement did not have predictive value when determining speed of improvement, response and remission with ECT. Other clinical factors, such as cognitive side-effects, may be more relevant when making the clinical choice between RUL and BT ECT.