Quick answer
For depression that has not responded to at least two antidepressants, ketamine is one of the most studied next-step options, and the evidence is genuinely encouraging. Clinical trials and real-world data show meaningful, often rapid improvement in a substantial share of people with treatment-resistant depression, including reductions in suicidal thinking within hours. It is not a cure and it does not work for everyone, but for a population that has run out of standard options, it is a serious, evidence-based choice. It is compounded and not FDA-approved, given under medical supervision, and results vary.
If you are in crisis, call or text 988 for the Suicide and Crisis Lifeline, or call 911 for an emergency.
How Well Does Ketamine Work for Treatment-Resistant Depression?
In studies of treatment-resistant depression, a meaningful portion of patients who had not responded to multiple antidepressants experience significant symptom reduction with ketamine, and some reach remission. Response rates vary across studies and individuals, so no honest provider quotes a guaranteed number. What is consistent is that ketamine helps a population that, by definition, had stopped responding to standard care.
The most reliable finding is speed. Where antidepressants take weeks, ketamine often shifts symptoms within a day or two. That speed is clinically important for people in deep depressive episodes or in crisis, where waiting six weeks is not safe.
How Fast Does Ketamine Work Compared to Antidepressants?
Ketamine commonly produces noticeable improvement within hours to a few days, while standard antidepressants typically need 4 to 6 weeks to take full effect. This difference is one of the main reasons ketamine is used in treatment-resistant cases and in situations involving acute suicidal thoughts, where rapid relief matters.
The tradeoff is durability. A single ketamine treatment's effect can fade over days to weeks, which is why it is delivered as a series rather than a one-time dose, and why pairing it with therapy and other supports is part of doing it well. For a side-by-side look at how the two approaches work, see ketamine vs antidepressants.
How Long Do the Effects of Ketamine Last?
The effects of a single ketamine session often last days to a couple of weeks, which is why an initial course is usually a series of sessions over a few weeks, followed by maintenance treatments spaced further apart. The goal is to extend and stabilize relief over time, not to rely on one dose.
How long relief lasts varies widely from person to person. Some people maintain gains with occasional maintenance sessions; others need a more structured schedule. Your provider tailors the plan based on how you respond and tracks it with standardized symptom measures.
Why Does Ketamine Work When Antidepressants Did Not?
Ketamine acts on the brain's glutamate system and appears to rapidly promote new synaptic connections, a completely different mechanism from the serotonin-focused action of most antidepressants. If your depression did not respond to serotonin-based drugs, a treatment that works through a separate pathway has a real chance of helping. Emerging research also links treatment-resistant depression to glutamate-system dysfunction, which fits why ketamine helps this group.
Care at Ascend: Learn more about Ketamine Therapy at Ascend Mind and Body, see our ketamine clinic in Wesley Chapel, or book an appointment.
Frequently asked questions
What counts as treatment-resistant depression?
Depression is generally called treatment-resistant when at least two different antidepressants, each taken at an adequate dose for 4 to 6 weeks, have not produced meaningful improvement. Stopping early due to side effects does not count as a failed trial. Our overview of treatment-resistant depression explains how it is assessed.
Does ketamine cure treatment-resistant depression?
No. Ketamine can produce meaningful and sometimes rapid relief, but it is not a permanent cure. Most people need a series of sessions plus a maintenance plan, and many pair it with therapy to consolidate gains.
Is ketamine safe for depression?
With proper screening and medical supervision, ketamine has a well-characterized safety profile for short-term therapeutic use. Candidacy evaluations screen for conditions like uncontrolled blood pressure, psychosis, and substance misuse that would make it unsafe.
Will insurance cover ketamine for depression?
Coverage is limited, and ketamine for mood conditions is often paid out of pocket. Ask your insurer which parts of your care, such as the initial evaluation and follow-up visits, may still be billable, and ask the clinic about cost and coverage before starting. See our full breakdown of ketamine therapy cost.
Does insurance cover ketamine for depression in Florida?
In Florida, as elsewhere, ketamine for depression is usually self-pay, because most Florida plans do not reimburse treatments that are not FDA-approved for the condition. Where a plan does consider any part of the care, prior authorization and documentation of previous antidepressant trials typically apply. Ask the clinic to verify your specific plan before starting.
Medically reviewed by
Anna Stouffer, PMHNP-BC
This article is for general educational purposes only and is not medical advice. It does not create a provider-patient relationship. Talk with a qualified Florida-licensed clinician about your individual situation.
Sources
- McIntyre RS, et al. Synthesizing the Evidence for Ketamine and Esketamine in Treatment-Resistant Depression. American Journal of Psychiatry, 2021. https://pubmed.ncbi.nlm.nih.gov/33726522/
- Wilkinson ST, et al. The Effect of a Single Dose of Intravenous Ketamine on Suicidal Ideation: A Systematic Review and Individual Participant Data Meta-Analysis. American Journal of Psychiatry, 2018. https://pubmed.ncbi.nlm.nih.gov/28969441/
- National Institute of Mental Health. Depression. https://www.nimh.nih.gov/health/topics/depression