Bitemporal v. high-dose right unilateral electroconvulsive therapy for depression: a systematic review and meta-analysis of randomized controlled trials

Psychol Med. 2017 Feb;47(3):518-530. doi: 10.1017/S0033291716002737. Epub 2016 Oct 26.


Background: Brief-pulse electroconvulsive therapy (ECT) is the most acutely effective treatment for severe depression though concerns persist about cognitive side-effects. While bitemporal electrode placement is the most commonly used form worldwide, right unilateral ECT causes less cognitive side-effects though historically it has been deemed less effective. Several randomized trials have now compared high-dose (>5× seizure threshold) unilateral ECT with moderate-dose (1.0-2.5× seizure threshold) bitemporal ECT to investigate if it is as effective as bitemporal ECT but still has less cognitive side-effects. We aimed to systematically review these trials and meta-analyse clinical and cognitive outcomes where appropriate.

Method: We searched PubMed, PsycINFO, Web of Science, Cochrane Library and EMBASE for randomized trials comparing these forms of ECT using the terms 'electroconvulsive' OR 'electroshock' AND 'trial'.

Results: Seven trials (n = 792) met inclusion criteria. Bitemporal ECT did not differ from high-dose unilateral ECT on depression rating change scores [Hedges's g = -0.03, 95% confidence interval (CI) -0.17 to 0.11], remission (RR 1.06, 95% CI 0.93-1.20), or relapse at 12 months (RR 1.42, 95% CI 0.90-2.23). There was an advantage for unilateral ECT on reorientation time after individual ECT sessions (mean difference in minutes = -8.28, 95% CI -12.86 to -3.70) and retrograde autobiographical memory (Hedges's g = -0.46, 95% CI -0.87 to -0.04) after completing an ECT course. There were no differences for general cognition, category fluency and delayed visual and verbal memory.

Conclusions: High-dose unilateral ECT does not differ from moderate-dose bitemporal ECT in antidepressant efficacy but has some cognitive advantages.

Keywords: Depression; electroconvulsive therapy; electrode placement; meta-analysis.

Publication types

  • Comparative Study
  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Depressive Disorder / therapy*
  • Electroconvulsive Therapy* / adverse effects
  • Electroconvulsive Therapy* / methods
  • Electroconvulsive Therapy* / statistics & numerical data
  • Humans
  • Outcome and Process Assessment, Health Care / statistics & numerical data*
  • Randomized Controlled Trials as Topic / statistics & numerical data*