Success Rates & Evidence
What the numbers actually say
No marketing hype. Here's the honest, peer-reviewed evidence on how often ketamine works — and for whom — drawn directly from clinical trials.
The data
Ketamine response rates in clinical research
Response = at least 50% reduction in symptom scores. Remission = scores drop to normal or near-normal range. Here's what the major trials show:
| Study / Population | Response Rate | Notes |
|---|---|---|
| Treatment-resistant depression (multiple trials) | 50-70% | vs. 33% for first antidepressant (STAR*D) |
| Bipolar depression (Zarate et al., Yale) | 60-71% | Single infusion, on mood stabilizer |
| PTSD (Feder et al., 2014) | 60% | At 24 hours post-infusion |
| Chronic pain (CRPS, neuropathy) | 30-60% | Smaller studies, more variable |
Sources: Kirsch et al., Lancet Psychiatry; Zarate et al., Biological Psychiatry; Feder et al., JAMA Psychiatry; Corriger & Niesters, Cochrane Review.
Response vs. remission
What 'working' actually means
Response (50-70%)
A meaningful reduction in symptom severity — enough that a patient or their family notices a difference. Measured objectively using validated scales (MADRS, PHQ-9, GAD-7). Most ketamine clinical trials report response rates, not remission rates, because meaningful improvement is achievable even when complete resolution isn't.
Remission (25-50%)
Complete or near-complete resolution of symptoms. In the STAR*D study of conventional antidepressants, only about 33% of patients achieved remission with a first medication — and 20% with the fourth. Ketamine offers significantly higher remission rates in treatment-resistant populations.
What real-world data shows
Beyond the clinical trial
Clinical trial populations are carefully selected — they may represent a different group than real-world patients with complex histories and multiple comorbidities. That said, real-world ketamine clinic data has generally been consistent with trial results.
A 2023 analysis of over 1,000 ketamine infusions at 18 US clinics found that 52% of patients with treatment-resistant depression had a clinically meaningful response, with 33% achieving remission. These real-world numbers are lower than in tightly controlled trials, but still substantially better than what conventional antidepressants achieve in the same population.
Common questions
Frequently asked questions
What is the success rate for ketamine therapy?
Across major clinical trials, 50-70% of patients experience a significant reduction in depressive symptoms after a series of IV ketamine infusions. In the STAR*D trial, the standard first-line antidepressant response rate was about 33%. For ketamine in treatment-resistant patients — those who've failed multiple antidepressants — many studies show 50-70% response rates, defined as at least a 50% reduction in symptom scores.
How do you define 'success' in ketamine research?
Researchers typically define response as a ≥50% reduction in symptom severity (measured by scales like MADRS or PHQ-9) and remission as achieving a score below a threshold (meaning symptoms are minimal or absent). Not every patient who responds achieves full remission — but even partial response can meaningfully improve quality of life.
Why do some people not respond to ketamine?
About 30-50% of patients don't respond to ketamine therapy. Factors that may predict non-response include: longer duration of depression, higher severity of baseline symptoms, presence of anxiety or PTSD comorbidities, and certain genetic factors. This doesn't mean ketamine won't work for you — many non-responders to a single condition respond to a different condition or to a different course of ketamine.
How long does the antidepressant effect last?
After a single ketamine infusion, antidepressant effects typically last days to weeks (median 2-3 weeks in many studies). After a full induction series (6 infusions), patients commonly report sustained improvement for weeks to months. With maintenance therapy (monthly or quarterly infusions), many patients maintain their improvement over the long term.
What percentage of patients achieve remission with ketamine?
Remission rates (complete or near-complete symptom resolution) are lower than response rates — typically 25-50% in clinical trials of IV ketamine for treatment-resistant depression. Response (meaningful improvement) rates are higher at 50-70%. Individual results vary based on condition severity, prior treatment history, and other factors.
Does ketamine work better for some conditions than others?
Ketamine has the strongest evidence base for treatment-resistant depression, with 40+ randomized controlled trials. The evidence for PTSD, anxiety, and bipolar depression is growing but smaller. The evidence for chronic pain is more limited but promising. We discuss the evidence base for your specific condition honestly during your consultation.
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