Electroconvulsive therapy, or ECT, is one of the treatments used for severe depression when other approaches haven't helped. It involves a controlled electrical pulse delivered to the brain under anaesthesia, and it has a long track record of effectiveness. Ketamine, a medication more commonly known as an anaesthetic, has more recently been used to treat depression too, often producing improvement more quickly than standard antidepressants.
A 2022 systematic review and meta-analysis by Rhee and colleagues looked at how ketamine compares with ECT for people experiencing a major depressive episode. Before this research, that comparison had not been clearly established.
The question matters for practical reasons. ECT requires anaesthesia and a medical team, and it can carry side effects such as memory difficulties. Ketamine is given differently and may be easier for some patients to access or tolerate. Understanding how the two treatments compare, in terms of both benefit and safety, helps clinicians and patients weigh up which option might suit a given person.
Work like this feeds into the conversations doctors and psychiatrists have with patients about treatment options for severe depression, particularly when earlier treatments haven't worked.
If you are living with depression, especially depression that hasn't responded to previous treatment, it is worth speaking with a GP or mental health professional about what might help in your situation. You don't need to work out the options on your own.
Making sense of the evidence: what a meta-analysis actually does
Before getting into results, it helps to understand the method. A systematic review is a structured search of the scientific literature, following a strict protocol, to find every relevant study on a question. A meta-analysis then pools the numerical results from those studies into one combined estimate, giving a more statistically powerful answer than any single trial could. Rhee et al. followed the PRISMA guidelines, a widely used reporting standard that makes systematic reviews transparent and checkable.
To compare depression outcomes across different studies (which often use different rating scales), researchers use a standardised mean difference (SMD), often calculated as Hedges g. This expresses the size of a treatment difference in a common statistical unit, independent of which specific scale was used. An SMD is reported with a 95% confidence interval (CI) — the range within which the true effect most likely lies — and researchers also check for heterogeneity (how much studies disagree with each other), often summarised by the I² statistic, where higher values mean more inconsistency between studies.
What the study did
Rhee et al. searched major databases (PubMed, MEDLINE, Cochrane Library, Embase) plus clinical trial registries, from the earliest records through April 2022. They included studies that diagnosed depression using standard criteria, directly compared ECT with ketamine, and measured depressive symptoms with validated tools. Six clinical trials met these criteria, totalling 340 patients (162 receiving ECT, 178 receiving ketamine). Five of the six were randomised controlled trials (RCTs) — the design considered most reliable for testing treatment effects, since patients are randomly assigned to a group, reducing bias. Notably, all six studies were conducted in inpatient settings and enrolled patients who were medically eligible for ECT, which matters for interpreting the results.
What it found
The pooled result showed an SMD of -0.69 (95% CI, -0.89 to -0.48) favouring ECT over ketamine for reducing depression severity. This is generally considered a moderate-to-large effect in psychological research. Heterogeneity between studies was low-to-moderate (I² = 39%), meaning the studies were reasonably consistent with each other. When it came to cognition and memory performance, or serious adverse events such as suicide attempts or deaths, there were no statistically significant differences between the two treatments. Each treatment did have its own distinct side-effect pattern: ketamine carried lower risk of headache and muscle pain, while ECT carried lower risk of blurred vision, vertigo, double vision/nystagmus (involuntary eye movements), and the short-lived dissociative or depersonalisation feelings (a sense of being detached from oneself or reality) sometimes caused by ketamine.
Why it matters, and its limits
This evidence suggests ECT may work better than ketamine at reducing depression severity in the acute phase of a major depressive episode, without a clear cognitive or safety trade-off. But the authors themselves flag that the underlying trials were of low-to-moderate methodological quality and often underpowered (too small to reliably detect smaller differences). The sample was also restricted to inpatients already eligible for ECT, so the findings may not extend neatly to outpatients or people who couldn't receive ECT for medical reasons. As the authors conclude, treatment choice should still be individualised and made together with a clinician.
If you're navigating a decision like this, please don't do it alone — a mental health professional can help you weigh these options for your own situation.