Ketamine Therapy

What Is Ketamine Therapy? How It Works for Depression

Ketamine therapy is the supervised use of low-dose ketamine to treat depression and related conditions that have not responded to standard treatment. Ketamine began as an anesthetic used safely for decades; at much lower doses it appears to act rapidly on the brain's mood circuits. Many people notice a shift within hours to days rather than the weeks antidepressants usually take. It is given under medical supervision, and results vary from person to person.

Reviewed by Anna Stouffer, PMHNP-BC Last reviewed 2026-06-01 3 min read

Quick answer

Ketamine therapy is the supervised use of low-dose ketamine to treat depression and related conditions that have not responded to standard treatment. Originally an anesthetic used safely for decades, ketamine at much lower doses appears to rapidly affect the brain's mood circuits. People often feel a shift within hours to days, rather than the weeks antidepressants usually take. It is given under medical supervision, and results vary from person to person.

If you are in crisis, call or text 988 for the Suicide and Crisis Lifeline, or call 911 for an emergency.

How Does Ketamine Work in the Brain?

Ketamine works mainly through the brain's glutamate system rather than the serotonin system that most antidepressants target. By blocking certain glutamate receptors, it appears to trigger a rapid increase in synaptic connections, a process researchers call synaptogenesis. In simple terms, it seems to help the brain form new connections quickly, which may be why relief can come faster than with traditional medications.

This different mechanism is the whole point. If you have not responded to drugs that adjust serotonin, a medication that works through an entirely separate pathway may help where the others have not. It is not better or worse than antidepressants; it is different, and that difference is what makes it useful for treatment-resistant cases.

What Conditions Does Ketamine Therapy Treat?

Ketamine therapy is used most for treatment-resistant depression, and there is a smaller and less settled body of evidence for its use in treatment-resistant anxiety, post-traumatic stress disorder, and the rapid reduction of suicidal thoughts. It is generally considered after standard treatments have been tried at adequate doses without enough relief, not as a first step.

Research has also reported rapid effects on suicidal thinking (Wilkinson et al., 2018); that is a research finding, not a service Ascend offers, and ketamine is not an emergency intervention. If you are in crisis, call or text 988. Suicidal ideation, where speed matters most. For chronic depression, it is typically delivered as a short series of sessions followed by a maintenance plan. A provider confirms your diagnosis and reviews your history before recommending it.

Is Ketamine Therapy the Same as Recreational Ketamine?

No. Therapeutic ketamine uses carefully measured low doses, in a clinical setting, with medical monitoring and a treatment plan, which is fundamentally different from recreational use. The goal is symptom relief, not intoxication, and the dosing and oversight are built around safety. Recreational misuse, by contrast, involves unregulated doses without monitoring and carries real risks, including bladder and cognitive harm with heavy long-term use.

What Forms Does Ketamine Therapy Come In?

Ketamine therapy is delivered as an IV infusion, an intramuscular or subcutaneous injection, a sublingual (under-the-tongue) lozenge, or as an intranasal spray. Each has tradeoffs in how precisely the dose is controlled, how it is monitored, and what it costs. The supervised in-clinic routes are the most studied. Ascend administers ketamine as a subcutaneous injection and does not offer IV, intranasal, or lozenge programs.

The right form depends on your diagnosis, your medical history, and the level of monitoring appropriate for you. This is a clinical decision made with a provider, not a menu to pick from on your own. If you are weighing the options, our guide to at-home vs in-clinic ketamine breaks down how the settings differ on evidence and monitoring.

Frequently asked questions

How quickly does ketamine therapy work?

Many people notice a change within hours to a few days, which is much faster than the 4 to 6 weeks antidepressants typically need. The initial effect can fade, which is why treatment usually involves a series of sessions and a maintenance plan.

Is ketamine therapy approved by the FDA?

Ketamine is not FDA-approved for mood conditions, and the ketamine used at Ascend is a compounded preparation, which is not FDA-approved for any use.

Does ketamine therapy require stopping my antidepressant?

Not usually. Many people continue their current medications during ketamine treatment, but your prescriber decides this individually. Do not change psychiatric medications on your own.

Who should not try ketamine therapy?

People with uncontrolled high blood pressure, unstable heart disease, active psychosis or mania, or active substance misuse involving ketamine should not undergo treatment until those issues are addressed. A candidacy evaluation screens for these. Our guide on whether ketamine therapy is right for you walks through candidacy in more detail.

Is ketamine therapy legal in Florida?

Yes. Generic ketamine is a Schedule III medication that Florida-licensed clinicians can prescribe for mood conditions, which is legal and common in medical practice. At Ascend, supervised ketamine sessions are conducted in Wesley Chapel.

Can I drive myself home after ketamine therapy?

No. Because ketamine temporarily affects coordination and judgment, you cannot drive for the rest of the day after a session and must arrange a ride home in advance. This applies to in-clinic infusions and to intranasal treatment, which requires a monitoring period before you leave.

Medically reviewed by

Anna Stouffer, PMHNP-BC

View clinician profile · Last reviewed 2026-06-01

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

  1. Krystal JH, et al. Ketamine: A Paradigm Shift for Depression Research and Treatment. Neuron, 2019. https://pubmed.ncbi.nlm.nih.gov/30844397/
  2. U.S. Food and Drug Administration. FDA approves new nasal spray medication for treatment-resistant depression. https://www.fda.gov/news-events/press-announcements/fda-approves-new-nasal-spray-medication-treatment-resistant-depression-available-only-certified
  3. National Institute of Mental Health. Depression. https://www.nimh.nih.gov/health/topics/depression

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