Ketamine Met a Noninferiority Benchmark Against ECT in a Depression Trial

A 2023 New England Journal of Medicine trial found intravenous ketamine noninferior to electroconvulsive therapy, or ECT, for short-term response in adults with treatment-resistant major depression without psychosis. The finding informs a difficult treatment decision, but it should not become a claim that ketamine replaces ECT for every form of severe depression.

What the trial compared

The ELEKT-D study randomized 403 patients at five clinical sites. Participants had been referred to ECT clinics and were assigned to a three-week course of ketamine or ECT. Some withdrew before starting their assigned treatment; 195 received ketamine and 170 received ECT.

The primary outcome was treatment response, defined as at least a 50% reduction on a patient-reported depression scale. Response occurred in 55.4% of the ketamine group and 41.2% of the ECT group. The trial met its prespecified statistical criterion for ketamine's noninferiority.

Noninferiority is a specific question

A noninferiority study asks whether a treatment is not worse than a comparator by more than a predefined margin. It is not simply an unrestricted contest to declare a universal winner. Interpretation depends on that margin, the patient population, the treatment protocols, and the outcomes selected.

The study was open-label: patients and clinicians knew the assigned treatment. Expectations and treatment preferences could influence self-reported symptoms and participation. Withdrawals before treatment also matter when evaluating how closely the findings reflect the original randomized comparison.

Different side-effect profiles

ECT was associated with a greater short-term reduction in memory recall on a study test, with gradual recovery during follow-up. Ketamine was associated with dissociation, while ECT had musculoskeletal adverse effects. Patient-reported quality-of-life improvement was similar between the treatment groups.

These findings support individualized discussion rather than a simplistic ranking. A person may weigh memory concerns, dissociation, anesthesia, medical conditions, previous treatment response, and practical access differently. A short study also cannot answer every question about maintenance treatment, repeated exposure, or eventual relapse.

Who do the results apply to?

The trial specifically concerned nonpsychotic treatment-resistant depression. It does not establish ketamine's equivalence to ECT in psychotic depression, catatonia, or every urgent psychiatric presentation. Those conditions can involve different evidence and clinical priorities. The study's three-week treatment comparison should remain visible in any headline.

The regulatory distinction is equally important. Intravenous ketamine for depression is off-label; the trial did not change ketamine's approved anesthetic indication. FDA-approved esketamine nasal spray is a different product with its own label and monitoring program. Patients considering either treatment should review the actual formulation, indication, safety plan, and longer-term care strategy with a qualified clinician. Neither option should be selected solely from one headline or marketed as a guaranteed cure.

Sources

• New England Journal of Medicine: ELEKT-D trial
• Full journal report
• FDA: Esketamine nasal spray prescribing information