ECT vs ketamine for depression: meta-analysis finds ECT improves symptoms faster

The question

For major depression, does electroconvulsive therapy (ECT) or ketamine given by injection or infusion reduce symptoms more, once you account for how quickly each works?

What they did

Researchers searched three medical databases for studies published up to 31 November 2024 comparing ECT with ketamine in people diagnosed with major depressive disorder. Studies had to have comparable treatment lengths and measure depression on a standard rating scale at two or more time points. Seven studies with 731 participants were included out of 1220 articles identified. Instead of comparing single end points, the team used a statistical model that treated time as a variable, so differences in when studies measured outcomes were less of a problem.

What they found

People in the ketamine groups started with lower (less severe) depression scores than those in the ECT groups (standardized mean difference, or SMD, -0.28; p = 0.018; 95% confidence interval -0.51 to -0.05). After adjusting for those baseline differences, ECT showed a faster rate of improvement over time (β = 0.018; p < 0.0001; 95% CI 0.009 to 0.026), roughly 0.02 SMD per day in favour of ECT. Projected out to four weeks, that amounted to a predicted difference of SMD = 0.59 (95% CI -0.26 to 1.43), which the authors describe as a moderate advantage for ECT.

The fine print

Only seven studies and 731 people were pooled, and the ketamine groups were less depressed at the start, which the analysis had to adjust for statistically. The headline four-week estimate has a wide confidence interval that includes no difference at all, so the size of the advantage is uncertain. The abstract reports no data on side effects, cognitive effects, relapse, or outcomes beyond four weeks, and does not state how many of the included studies were randomized. This summary is based on the abstract alone.

What it means

Pooled evidence suggests ECT reduces depression symptoms faster than injected ketamine over a four-week course, though the size of that difference remains uncertain and this analysis says nothing about side effects or longer-term results.

Evidence grade: Moderate. A meta-analysis of seven comparative studies with 731 people, but the groups differed at baseline and the key four-week estimate is imprecise.

This summary is based on the study’s published abstract.