One of the first things people ask before starting ketamine therapy for depression is how many sessions this will take. Most people do not want vague answers when they are already dealing with depression and trying to make a careful treatment decision.
There is a common starting pattern, but the total number usually changes based on how someone responds. This article walks through the usual structure, why the number varies, and how clinicians decide what makes sense over time.
Quick Answer Summary
Most ketamine treatment plans for depression begin with an induction phase of about six sessions over two to three weeks, followed by a personalized maintenance schedule. Research shows early symptom relief can occur within days, while ongoing booster sessions—often spaced every few weeks—help sustain improvement. The total number of treatments varies based on symptom severity, prior treatment history, response speed, and whether therapies like CBT are added to prolong benefits.
The Initial Induction Phase
Most ketamine programs begin with a short, more frequent phase, often called induction. In practice, this is where the familiar 6-session framework comes from.
A widely cited U.S. randomized trial from Yale and collaborating institutions used 6 intravenous ketamine infusions over 3 weeks for adults with treatment-resistant depression. In that study, 42 patients consented, and 28 later achieved a clinical response and moved into the next phase of care planning.
That same logic shows up in FDA-approved esketamine scheduling. The 2025 FDA prescribing information for Spravato lists an induction pattern with dosing twice per week in the early phase, then lower frequency afterward, and it specifically says clinicians should evaluate therapeutic benefit at the end of induction before deciding what comes next.
So even though IV ketamine and intranasal esketamine are not identical treatments, the treatment rhythm is similar: Early sessions are intentionally clustered to create momentum.
Maintenance and Boosters
After induction, most people do not stay on the same schedule forever. This is the point where ketamine treatment becomes more personalized.
The VA 2024 study gives a clear, real-world picture. In that veteran cohort, infusion frequency decreased from about every 5 days to every 3 to 4 weeks over the first 5 months, and patients received a mean of 18 total infusions over 12 months. The same paper noted that symptom improvements seen within the first 6 weeks stayed similar at 12 and 26 weeks, while frequency was reduced. That is a strong example of why maintenance exists: The goal is to hold gains with fewer sessions when possible.
The FDA labeling for Spravato outlines a gradual taper in visit frequency. Treatment starts more often, usually twice a week, then shifts to weekly sessions, and later moves to weekly or every two weeks based on how the patient is doing. The guidance also says clinicians should use the lowest frequency that still maintains improvement or remission. In practice, that is why booster sessions are viewed as routine maintenance, not a setback.
Factors That Influence Treatment Number
The total number of sessions depends on more than a diagnosis label. Clinicians usually look at several variables together before setting or changing a plan for ketamine infusion therapy.
Symptom Severity and Chronicity
People with long-standing, severe depression often need a longer runway before improvement becomes clear. In the VA group, the average starting PHQ-9 score was 18.6, showing substantial depression symptoms at baseline, and many patients still required continued treatment after the initial phase.
Previous Treatment History
In the same VA study, patients had a mean of 2.1 antidepressant trials in the past year and 6.1 trials over the prior 20 years. That is the kind of history that usually signals treatment resistance and helps explain why clinicians lean toward structured, repeated sessions instead of one-off dosing.
Individual Response Patterns
Response speed varies a lot. In the 2025 U.S. multicenter esketamine monotherapy trial, some participants showed measurable improvement by day 2, roughly 24 hours after the first dose. Researchers still followed outcomes through day 28, since early relief can shift. The study included 378 adults across 51 outpatient centers.
Co-occurring Conditions
Anxiety and trauma symptoms can shape both the treatment experience and the pace of improvement. In real clinical settings, many ketamine programs assess patients with treatment-resistant depression who also have PTSD or anxiety. That overlap is common, so providers usually factor it into timing, monitoring, and expectations from the start.
Integration Work
This part gets overlooked, but it matters. The Yale 2021 randomized trial tested CBT after ketamine and found a significant group-by-time interaction on one depression measure, favoring sustained improvement with CBT support. It was a small study, so it should not be overstated, but it supports the idea that therapy can affect how long benefits last and, by extension, how often boosters may be needed.
What Response Looks Like Over Time
Improvement does not always arrive in a clean, dramatic way. Sometimes it does. Often it comes in pieces.
The 2025 esketamine monotherapy trial showed that relief can begin early, sometimes within a day, but the bigger pattern becomes easier to see over a few weeks. By day 28, both esketamine doses outperformed placebo, with average MADRS score differences of 5.1 points for 56 mg and 6.8 points for 84 mg.
Some people feel relief after the first one or two sessions. Others notice smaller changes first, like less mental heaviness or better sleep, then stronger mood improvement later. Partial response still counts because it helps clinicians decide whether to continue, adjust timing, or combine care differently.
How Treatment Plans Evolve
The number of sessions is not fixed on day one. Clinicians reassess regularly, and the plan moves with the patient.
The FDA label for Spravato explicitly ties dosing decisions to ongoing evaluation and requires supervised administration with post-dose monitoring for at least 2 hours because of safety risks like sedation, dissociation, and respiratory depression.
It is also restricted through the Spravato REMS program, which means treatment must happen in certified settings. Those details shape the treatment plan just as much as symptom scores do.
Real-world treatment also changes based on tolerability. In the 2025 esketamine monotherapy trial, nausea affected 24.8% of patients, dissociation 24.3%, dizziness 21.7%, and headache 19.0%. Clinicians track these patterns closely when adjusting session timing and follow-up for each patient.
Build Your Personalized Path
The usual foundation is a short induction series, and 6 treatments are a common starting point for IV care, but the total number is rarely one-size-fits-all. The bigger goal is not to hit a magic number but to build a plan that creates lasting relief and still fits your symptoms, response pattern, and life.
At Zeam, we provide several ketamine treatment options, including IV ketamine, Spravato, and therapy-supported care. We do not force everyone into the same schedule because treatment works best when it fits the person. If you are exploring ketamine therapy in Sacramento, Folsom, or Roseville, our team can walk you through what a personalized plan may involve, what the timeline can look like, and what comes next. Reach out to schedule a consultation.
Key Takeaways
- A common starting point for IV ketamine is six infusions over about three weeks, forming the induction phase.¹
- FDA guidance for esketamine follows a similar pattern: frequent early dosing, then tapering to weekly or biweekly maintenance based on response.²
- Real-world data show treatment frequency often decreases from every few days to every 3–4 weeks, with patients averaging about 18 total infusions over one year.³
- Some patients experience measurable improvement within 24 hours, but clinicians reassess over several weeks to confirm durable response.⁴
- Side effects such as nausea, dissociation, dizziness, and headache are monitored in supervised clinical settings and influence scheduling decisions.²
- Adding CBT after ketamine may help sustain symptom improvement and reduce the need for frequent boosters.¹
- Treatment plans are individualized, with maintenance sessions used to preserve gains rather than signal relapse.
Citations
- Cognitive Behavioral Therapy to Sustain the Antidepressant Effects of Ketamine — Karger. (https://karger.com/pps/article-abstract/90/5/318/829016/Cognitive-Behavioral-Therapy-to-Sustain-the?redirectedFrom=fulltext)
- Spravato (esketamine) Prescribing Information, FDA, 2025. (https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/211243s016lbl.pdf)
- Clinical Outcomes of Intravenous Ketamine for Depression in the VA Health System — Journal of Clinical Psychiatry. (https://www.psychiatrist.com/jcp/clinical-outcomes-intravenous-ketamine-for-depression-va-health-system)
- Multicenter Esketamine Monotherapy Trial — PMC. (https://pmc.ncbi.nlm.nih.gov/articles/PMC12224050/)
