Ketamine treats depression through low-dose infusions or a nasal spray, typically relieving symptoms within hours rather than the weeks required by traditional antidepressants. It’s primarily used for treatment-resistant depression, meaning cases where at least two other medications haven’t worked. The treatment is always administered in a medical setting under direct supervision.
Why Ketamine Works Differently
Traditional antidepressants target serotonin or similar chemical messengers and can take four to six weeks to show results. Ketamine works through an entirely different system: glutamate, the brain’s most abundant chemical signal. By blocking certain glutamate receptors, ketamine triggers a cascade that increases connections between brain cells in areas involved in mood regulation. Think of it as helping the brain rapidly rebuild communication pathways that depression has weakened or severed.
This rewiring process, called synaptogenesis, is driven by a growth factor called BDNF that acts like fertilizer for nerve cells. Ketamine ramps up production of this growth factor, which then activates pathways responsible for forming new synaptic connections. The result is measurable changes in brain plasticity that correspond with the rapid mood improvement patients experience, sometimes within hours of a single session.
Two Forms: IV Infusion and Nasal Spray
Ketamine for depression comes in two main forms, and they differ in how they’re regulated, administered, and covered by insurance.
IV Ketamine
Intravenous ketamine is the most studied form. The standard dose is 0.5 mg/kg of body weight, delivered slowly through an IV over 40 minutes. For patients with a BMI over 30, providers typically calculate the dose based on ideal body weight rather than actual weight to avoid over-dosing. IV ketamine for depression is considered “off-label,” meaning the drug itself is FDA-approved (originally as an anesthetic) but not specifically approved for depression. This distinction matters because insurance coverage is inconsistent, and out-of-pocket costs can run several hundred dollars per session.
Esketamine Nasal Spray (Spravato)
Esketamine is a closely related compound that the FDA approved in 2019 specifically for two conditions: treatment-resistant depression in adults, and depressive symptoms with acute suicidal thoughts or behavior. It’s self-administered as a nasal spray, but only inside a certified healthcare setting. You cannot take it home. After each dose, a healthcare provider monitors you for at least two hours before you’re cleared to leave. This restriction exists because of risks including sedation, dissociation, and the potential for misuse. Every clinic that offers Spravato must be enrolled in a special safety program called a REMS, and every patient must be registered in that program as well.
What a Treatment Course Looks Like
Both forms follow a similar pattern: an intensive initial phase followed by gradual tapering. For IV ketamine, the Department of Veterans Affairs protocol calls for sessions no more than twice a week, spaced at least two days apart, over a four-week induction period. That means roughly six to eight infusions in the first month.
Esketamine follows a comparable schedule. Treatment typically starts at twice a week for the first month. If symptoms improve, frequency decreases to weekly, then every two weeks, then monthly. The maintenance phase can last several weeks to months depending on how you respond. Your provider adjusts the schedule based on how long your symptom relief holds between sessions.
Each session itself is relatively brief. The infusion or nasal spray administration takes under an hour, but you should plan for a longer visit. With the required two-hour observation period, plus check-in time, expect to spend about three hours at the clinic per session. You’ll need someone to drive you home, as the medication causes temporary cognitive effects that make driving unsafe the same day.
How Quickly It Works
Speed is ketamine’s defining advantage. Symptoms can begin easing within hours of the first treatment. For many patients, noticeable improvement comes within the first one to three sessions. Relief from a single infusion can last days to weeks, though it does wear off, which is why repeated treatments are necessary.
Not everyone responds. The research on response rates varies, but a significant portion of patients with treatment-resistant depression do experience meaningful symptom reduction. The effect tends to build over the induction phase, with each session reinforcing the previous one. Some people who don’t notice much after the first infusion improve after subsequent sessions.
Side Effects During Treatment
Ketamine’s most common side effects happen during or shortly after administration and resolve within a couple of hours. Dissociation is the most distinctive: a feeling of being detached from your body or surroundings, sometimes described as dreamlike or floaty. This is temporary and is part of why the two-hour monitoring period exists.
Other common effects include nausea, dizziness, increased blood pressure, and a sense of sedation. Blood pressure typically rises during the infusion and returns to normal afterward. Providers monitor your vitals throughout the session. Some patients find the dissociative experience unsettling, while others describe it as neutral or even pleasant. The intensity of side effects often decreases with repeated treatments as you become familiar with the sensation.
Who Can and Cannot Receive Ketamine
Ketamine therapy isn’t appropriate for everyone with depression. It’s specifically designed for people who haven’t responded to conventional antidepressants, not as a first-line treatment. Before starting, you’ll go through screening to rule out conditions that make ketamine unsafe.
- Active substance use disorders disqualify most candidates. Clinics may require a negative drug screening before starting treatment and periodically throughout the course.
- History of psychosis is a firm exclusion, as ketamine’s dissociative properties can worsen psychotic symptoms.
- Uncontrolled high blood pressure or unstable heart disease are contraindications because ketamine raises blood pressure and heart rate.
- Pregnancy rules out treatment due to unknown risks to fetal development.
- Elevated pressure inside the skull is another exclusion, as ketamine can increase intracranial pressure.
- Previous bad reaction to ketamine would also disqualify you from further treatment.
Cost and Access
Access depends heavily on which form you’re pursuing. Esketamine (Spravato) has FDA approval for depression, which means insurance is more likely to cover it, though prior authorization is common and you’ll typically need documented failure of at least two antidepressants. IV ketamine, being off-label, is less consistently covered. Many clinics offering IV infusions operate on a cash-pay model, with individual sessions ranging from roughly $400 to $800. A full induction course can cost several thousand dollars.
Availability is also a factor. Certified Spravato clinics are concentrated in urban and suburban areas. IV ketamine clinics have expanded rapidly in recent years, but geographic coverage remains uneven. Some providers offer both options and can help determine which route makes the most sense given your insurance situation and clinical profile.