Can Ketamine Improve Electroconvulsive Therapy for Depression?

What you need to know

• Electroconvulsive therapy (ECT) remains the most effective treatment for major depression, especially treatment-resistant cases.
• Recent studies have examined whether using ketamine as the anesthetic for ECT could enhance its antidepressant effects or reduce cognitive side effects.
• Meta-analyses suggest ketamine may accelerate antidepressant response to ECT but does not increase its overall efficacy or improve cognitive outcomes.

Background on ECT and Ketamine

Electroconvulsive therapy (ECT) involves applying electrical currents to the brain to trigger a brief seizure. It is considered the most effective treatment for severe, treatment-resistant depression, with response rates of 65-80%. However, ECT can cause temporary cognitive side effects, particularly memory issues.

Ketamine is an anesthetic drug that has been approved for use in ECT. In recent years, studies have found that ketamine itself has rapid antidepressant effects when given intravenously at low doses. This led researchers to investigate whether using ketamine as the anesthetic for ECT could enhance its antidepressant effects or reduce side effects.

Potential Benefits of Ketamine in ECT

Some proposed advantages of using ketamine as the anesthetic for ECT include:

• It may lower the seizure threshold, allowing for effective seizures with less electrical current
• It could potentially reduce cognitive side effects like short-term memory loss
• It provides pain relief that continues after the procedure
• It can be given intramuscularly if needed
• It may be safer for patients with certain conditions like porphyria or lung disease

Review of Research Findings

The author reviewed six meta-analyses that examined randomized controlled trials comparing ECT with ketamine anesthesia to ECT with other anesthetics. Key findings include:

• Some evidence that ketamine may accelerate the onset of antidepressant effects in the first 1-2 weeks of ECT
• No clear advantage in overall antidepressant efficacy by the end of the ECT course
• No consistent evidence that ketamine reduces cognitive side effects
• Possible increased risk of confusion and delirium immediately after ECT with ketamine

The author notes that many of the individual studies had small sample sizes and methodological differences that make it difficult to draw firm conclusions.

Recent Studies

The review also discusses some recent studies not included in the meta-analyses:

• A 2020 study (Brunelin et al.) found no benefit to adding low-dose ketamine to propofol anesthesia for ECT. The ketamine group actually had worse outcomes.

• A 2021 study (Zou et al.) in older adults found faster antidepressant effects with ketamine + propofol after 4-6 ECT sessions, but no difference in overall efficacy or cognitive outcomes.

• A 2020 study (Chen et al.) found patients receiving ketamine + propofol needed 1-3 fewer ECT sessions to achieve response/remission compared to propofol alone.

Conclusions

• The available evidence suggests ketamine anesthesia may accelerate the initial antidepressant response to ECT.
• However, it does not appear to increase the overall efficacy of ECT or consistently reduce cognitive side effects.
• Larger, well-designed studies are still needed to definitively determine the risks and benefits of using ketamine anesthesia for ECT in depression.

The author concludes that while ketamine shows some promise for potentially enhancing ECT, more research is needed before it can be recommended as a standard approach. Clinicians should weigh the potential risks and benefits for individual patients when considering ketamine anesthesia for ECT.