Bipolar depression has one of the shortest treatment shelf lives in psychiatry. For decades, the list of approved options has stayed thin, and most of what’s on it comes with side effects that are hard to live with. A randomized trial published in JAMA Psychiatry 2026 (Orsini, Di Luch, Rosenblat et al.) adds a new name to the conversation for people who have run out of good choices: IV ketamine for bipolar depression.
This article walks through what the Ket-BD study found, why the finding matters, where the evidence is still cautious, and what it means for anyone weighing their options. IV ketamine is a low dose of the anesthetic ketamine delivered slowly through an IV under medical supervision, a very different thing from a daily pill.
The short answer
In the Ket-BD trial, adults with treatment-resistant bipolar I or II depression who received four ketamine infusions over two weeks improved more than those who received a placebo-like comparison drug. The improvement was clinically meaningful, and, importantly, ketamine did not trigger mania or psychosis in this group. The study was small, and one contrasting trial urges caution, so this is promising early evidence rather than a settled conclusion.
If you or someone you love lives with bipolar depression, that nuance matters. Let’s unpack it.
Why bipolar depression is so underserved
People often picture bipolar disorder as the manic highs. In practice, most of the illness is spent in the depressive lows. And the menu for treating those lows is remarkably short.
Only a handful of medications carry an FDA label for acute bipolar depression:
- Quetiapine (Seroquel): bipolar I and II depression
- Lurasidone (Latuda): bipolar I depression
- Cariprazine (Vraylar): bipolar I depression
- Lumateperone (Caplyta): bipolar I and II depression
- Olanzapine–fluoxetine combination (Symbyax): bipolar I depression
Nearly all of these are atypical antipsychotics. They can help, and for many people they do. But they also carry side effects that are genuinely hard to tolerate: weight gain, metabolic changes, restlessness (akathisia), and, with long-term use, movement disorders like tardive dyskinesia. Lithium, the most famous mood stabilizer, is valuable for long-term stability but isn’t a treatment for an acute depressive episode.
There’s also an economics problem behind the short list. Fewer people live with bipolar depression than with unipolar (major) depression, so when a company develops a new antidepressant, it has a strong incentive to study and label it for the larger market. Bipolar depression trials are also harder to win: the drug-versus-placebo gap tends to be narrow because bipolar depression can lift on its own, and quickly. Smaller market plus higher trial risk is a discouraging combination for anyone deciding where to invest. The result is a field that’s been slow to add genuinely new options.
That’s the backdrop that makes a positive, controlled trial worth paying attention to.
What the Ket-BD study found about IV ketamine for bipolar depression
The Ket-BD study (Ketamine for Treatment-Resistant Bipolar Disorder) was an investigator-led, double-blind, randomized clinical trial run at three sites in Ontario, Canada, and published in JAMA Psychiatry. Here’s the design in plain terms, per MedPage Today’s coverage of the results:
- Who: 63 adult outpatients, ages 21–65, with bipolar I or II disorder in a moderate-to-severe depressive episode (a Montgomery-Åsberg Depression Rating Scale, or MADRS, score of at least 21). Everyone had already failed at least two evidence-based medications.
- What: Four flexibly dosed, 40-minute infusions of either ketamine (0.5–0.75 mg/kg) or midazolam (0.02–0.03 mg/kg) over two weeks. Midazolam is a sedative used as an “active placebo” because it produces some short-term effects, which helps keep the study blinded.
- On top of usual care: Everyone stayed on a stable dose of at least one mood stabilizer or antipsychotic. So this tested ketamine as an add-on, not a replacement.
- The main measure: Change in MADRS depression score from the start to day 14.
The MADRS (Montgomery-Åsberg Depression Rating Scale) is a standard clinician-rated tool for measuring how severe depression is. A higher score means more severe symptoms.
The result: At day 14, depression scores were significantly lower in the ketamine group than in the midazolam group, with a between-group difference of –7.3 points on the MADRS (95% CI, –12.0 to –2.5; P=0.003). Response rates, meaning a reduction of more than half in symptoms, were 35.3% with ketamine versus 11.8% with midazolam, and remission rates were 17.6% versus 8.8%. The advantage for ketamine held for about a week after the final infusion.
A 7-point difference isn’t a rounding error. Researchers generally consider a 7-to-9-point change on the MADRS to be the smallest difference that’s clinically meaningful, so this landed right in that range.
Just as important is what didn’t happen. Lead author Joshua D. Rosenblat, MD, and colleagues reported that ketamine “was not associated with treatment-emergent mania or psychosis,” the exact safety worry that has historically kept people with bipolar disorder out of ketamine trials. In his words, if other treatments aren’t working, “it would be reasonable to consider ketamine” as a second-line option.
The honest caveats
Good news deserves an honest frame, so here’s where the picture stays cautious.
The trial was small. Sixty-three participants is enough to detect a signal, not enough to settle the question. Larger trials are needed before anything changes at the level of FDA labels or insurance coverage.
Blinding is hard with ketamine. About 47% of participants correctly guessed which treatment they’d received after the very first infusion, largely because ketamine produces noticeable dissociation, a temporary sense of feeling detached from your body, thoughts, or surroundings, that midazolam doesn’t fully mimic. When people can tell what they’re getting, expectation can color the results.
Not every ketamine trial agrees. A separate 2025 JAMA Psychiatry trial, KARMA-Dep 2, tested serial ketamine infusions against midazolam in 65 hospitalized adults with unipolar or bipolar depression and found no significant difference between the two. Both groups improved substantially. Different setting (inpatient), different population, but a real reminder that the evidence isn’t uniform. When credible trials disagree, the responsible reading is “promising and worth studying further,” not “proven.”
There’s still no FDA-approved ketamine for bipolar depression. IV ketamine is used off-label. A related medication, esketamine (Spravato), a nasal spray derived from ketamine, is FDA-approved for treatment-resistant unipolar depression, but not for bipolar depression. Off-label doesn’t mean unsafe; it means the treatment is used based on clinical evidence and judgment rather than a specific regulatory label.
Why the medical setting is the whole point
Ketamine’s safety profile in a study like Ket-BD is inseparable from how it was delivered: precise, weight-based dosing, slow infusion, and continuous monitoring by clinicians. That’s the model that makes the risk-benefit math work, and it’s the difference between a carefully supervised medical treatment and an unpredictable one.
For bipolar disorder specifically, supervision does a few concrete jobs:
- Screening comes first. A thorough medical and psychiatric evaluation confirms the diagnosis, reviews your full medication list, and checks for anything that would make ketamine a poor fit.
- Mood-stabilizer coverage is confirmed. In Ket-BD, everyone stayed on a stabilizer or antipsychotic. Coordinating ketamine on top of your existing regimen, not instead of it, is central to using it safely in bipolar disorder.
- Real-time monitoring. Vitals and your subjective experience are watched throughout, and the dose is controlled to the person, not to a fixed script.
At Nushama, this is how ketamine care is structured: physician-led IV ketamine infusions, dosed and supervised by clinicians, with comprehensive screening before anyone begins. For people with bipolar disorder, that means confirming mood-stabilizer coverage and coordinating with your existing prescriber, the approach we describe in our guide to ketamine for bipolar disorder.
Where preparation and integration fit
A single number on a depression scale doesn’t capture what recovery feels like. The infusion is a catalyst; what surrounds it helps turn a two-week signal into durable change.
That’s the role of integration, the reflective work, often with a therapist or coach, of making sense of what came up during a session and translating it into everyday life. Preparation before a series and integration afterward aren’t extras layered on top of the medicine. For lasting change, they’re part of the treatment. Environment matters too: a calm, private, well-supported setting supports the kind of inner work this care asks of people.
What this means for you
If you live with bipolar depression and the standard medications either haven’t worked or have worn you down with side effects, the Ket-BD study is a genuine reason for measured hope. It’s the first randomized trial to test a full course of ketamine specifically for treatment-resistant bipolar depression, and the result was both positive and, on the safety front, reassuring.
It’s also not a finish line. The evidence is early, the trial was small, and ketamine for bipolar depression remains an off-label treatment that belongs in careful medical hands. The right next step isn’t a leap. It’s a conversation.
If you’re wondering whether supervised IV ketamine might fit your situation, speak with our care team. A consultation is a low-pressure way to ask questions, review your history, and understand what a safe, medically supervised path could look like for you.
2026 Mar 4;17:1777402. doi: 10.3389/fpsyt.2026.1777402
