Role of Anesthesia in ECT for Major Depressive Disorder

Electroconvulsive therapy (ECT) is an established treatment of major depressive disorder (MDD), particularly in severe cases and in cases resistant to pharmacological interventions. Anesthesia plays an important role in optimizing patient tolerability during ECT but may attenuate the treatment effect, as anesthetic agents elevate the seizure threshold. This review aims to examine the impact of commonly used anesthetics as well as the timing and dosing of anesthetics on seizure dynamics, patient safety and tolerability, and clinical outcomes of ECT for MDD. A systematic search was conducted in PubMed on September 23, 2024. Keywords included "anesthesia," "ECT," and "depression." Fifty-nine clinical trials, observational studies and meta-analyses were selected for in-depth analysis. We found that ketamine and etomidate are associated with longer seizures than other anesthetic agents. The use of etomidate is limited by its suppression of the adrenal synthesis of cortisol. Ketamine can, to a greater extent than other anesthetics, cause depersonalization, derealization, and audio-visual perceptual alterations. Lower doses of anesthesia and longer intervals between anesthetic administration and ECT have been related to longer seizures and also increased likelihood of response to ECT for MDD, although this has not yet been demonstrated in randomized controlled trials. Clinical outcomes are generally similar among different anesthetics, though ketamine anesthesia is associated with a more rapid effect of ECT. The choice of an anesthetic should be based on patient-specific factors such as cardiovascular health. Further research on optimized anesthetic dosing and timing is needed, especially with a focus on the clinical outcome of ECT.