KARMA-Dep 2: Serial Ketamine Infusions for Inpatient Depression

Depression severe enough to require hospitalization represents one of the most difficult clinical challenges in psychiatry. Standard inpatient care typically involves medication adjustments and supportive therapy, but many patients are discharged without meaningful improvement. The KARMA-Dep 2 trial, published in JAMA Psychiatry in 2024, asked a straightforward question: can serial ketamine infusions, added to standard inpatient care, produce faster and more robust relief?

What Was the KARMA-Dep 2 Trial?

KARMA-Dep 2 was a multicenter, randomized controlled trial (RCT) conducted across several French hospitals. Researchers enrolled adults hospitalized for a major depressive episode who had not responded adequately to at least one prior antidepressant trial. This population, often described as having treatment-resistant depression (TRD), faces limited options when conventional medications fail.

Participants were randomly assigned to receive either serial intravenous ketamine infusions or a saline placebo, administered three times per week over a two-week period, alongside their standard inpatient psychiatric care. The primary outcome was the change in Montgomery-Asberg Depression Rating Scale (MADRS) scores at the end of the infusion series.

Key Findings

The results were notable. Patients receiving ketamine showed significantly greater reductions in MADRS depression scores compared to those receiving placebo. The treatment effect was clinically meaningful, not just statistically significant, with a substantial proportion of ketamine-treated patients meeting criteria for treatment response (50% or greater reduction in depression scores) and remission.

Several additional findings stood out:

• Speed of response: Improvements began appearing after the first few infusions, consistent with ketamine's known rapid-acting antidepressant properties.
• Serial dosing matters: The trial demonstrated that repeated infusions over two weeks produced cumulative benefits, with each session building on the last. This contrasts with single-infusion studies where effects often fade within days.
• Safety profile: Adverse events were largely transient dissociative symptoms and mild hemodynamic changes during infusions. No serious safety signals emerged, and the side effects resolved shortly after each session ended.
• Adjunctive design: Importantly, ketamine was added to existing care rather than replacing it. Patients continued their antidepressants, psychotherapy, and other treatments throughout.

Why This Trial Matters

The KARMA-Dep 2 trial is significant for several reasons. First, it studied one of the hardest-to-treat populations: hospitalized patients with TRD. Positive results in this group suggest the treatment effect is robust and not limited to milder forms of depression.

Second, the serial infusion protocol provides a practical framework. Earlier ketamine research often used single infusions, which produce dramatic but short-lived improvements. By establishing that repeated dosing extends and deepens the benefit, KARMA-Dep 2 supports treatment protocols that aim for sustained relief rather than a temporary reprieve.

Third, the adjunctive approach aligns with how ketamine therapy is increasingly being used in clinical practice. Rather than asking clinicians to choose between ketamine and traditional treatments, the data supports combining them for greater impact.

How This Connects to Outpatient Ketamine Therapy

While KARMA-Dep 2 focused on inpatient IV infusions, the underlying principle of serial ketamine dosing applies across treatment settings. At-home sublingual ketamine protocols, like those used at Isha Health, follow a similar logic: repeated sessions over a defined period to build cumulative neuroplastic and antidepressant effects.

Isha Health's clinical outcomes data from real-world patients demonstrates this principle in practice, showing significant and sustained improvements across multiple measures of depression and anxiety.

The trial also reinforces the importance of medical supervision during ketamine treatment. Even in a controlled hospital environment, careful monitoring was essential to manage the transient side effects that accompany each session.

What Patients Should Know

If you or a loved one has been hospitalized for depression, the KARMA-Dep 2 results offer a reason for cautious optimism. Serial ketamine infusions represent a genuine advancement for patients who have not responded to standard medications. While inpatient IV protocols are not widely available at every hospital, the growing evidence base is pushing more institutions to adopt them.

For patients seeking ketamine therapy outside of inpatient settings, at-home treatment options now make serial dosing protocols accessible without hospitalization. The key is working with a physician-led program that monitors progress and adjusts treatment as needed.

The Bottom Line

KARMA-Dep 2 adds rigorous, multicenter RCT evidence to the case for serial ketamine dosing in severe depression. The results confirm that repeated ketamine sessions, layered on top of standard psychiatric care, can meaningfully accelerate recovery for patients who have run out of conventional options.

Considering ketamine therapy? Isha Health offers physician-led at-home treatment with an 88.8% improvement rate. Check appointment availability.