Effects of Ketamine Anesthesia on Efficacy, Tolerability, Seizure Response, and Neurocognitive Outcomes in Electroconvulsive Therapy
Bibliographic record
Abstract
Electroconvulsive therapy (ECT) remains the most effective treatment for major depressive disorder. Ketamine is an anesthetic gaining attention for its rapid antidepressant effect. Numerous randomized controlled trials have investigated the effect of ketamine anesthesia in ECT on various clinical outcomes. Previous systematic reviews have not found benefit for overall depression response, although some have found evidence of benefit early in the ECT course. Clear quantitative conclusions have not been established regarding other outcomes, particularly while only using data from high-quality studies. We aimed to examine all data from double-blind randomized controlled trials comparing ketamine to other anesthetics via meta-analysis, to make recommendations regarding ECT practice and future research. Data were extracted for depressive symptoms, seizure duration and electrical dose, neuropsychological performance, and adverse effects. Effect sizes were calculated using Hedge's g and odds ratios. Eighteen studies (n = 915) were included in the meta-analysis. Ketamine was not found to enhance improvement of depressive symptoms, either early in ECT course or at end of study. Ketamine had a large effect on increasing seizure duration both overall (Hedge's g = 0.71, P = 0.038) and in the subgroup receiving ketamine in combination with another anesthetic (Hedge's g = 0.78, P < 0.01), and on decreasing electrical dose (Hedge's g = 1.98, P = 0.039). There was no significant effect of ketamine on any individual neuropsychological domain. Ketamine was not associated with increased adverse effects, except for hypertension in patients receiving ketamine monotherapy. Significant heterogeneity was present for many outcomes, and sensitivity analyses suggested a relation to methodological variation in most cases. This study supports the finding that ketamine does not enhance ECT's antidepressant effect, including on early improvement, but provides substantial evidence for enhancing seizure duration and reducing electrical dose. No significant benefit was found on neurocognitive outcomes, but analysis was limited by small sample sizes and high heterogeneity. Ketamine is generally safe in ECT, particularly as a coanesthetic. Our findings provide meta-analytic support to the recommendations in ECT clinical guidelines for use of coadjuvant ketamine in ECT where seizures are suboptimal. Further studies targeting neurocognitive outcomes are encouraged.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.011 | 0.029 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.005 | 0.015 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".