What is Ketamine Therapy?
Ketamine therapy is a medical intervention that uses ketamine, a dissociative anesthetic, to treat psychiatric conditions—primarily treatment-resistant depression, PTSD, anxiety, and suicidal ideation. Ketamine began as a safer anesthetic in 1962, gaining FDA approval in 1970. Since the 2000s, research has documented rapid antidepressant effects occurring within hours rather than weeks, distinguishing ketamine from traditional psychiatric medications. It is administered in clinical settings via intravenous (IV) infusion, intramuscular injection, or sublingual tablets, sometimes paired with structured psychotherapy.
Ketamine is currently the only safe, effective and legal widely available psychedelic-like medicine. Unlike classical psychedelics such as psilocybin or MDMA, ketamine operates as an NMDA receptor antagonist, temporarily disrupting glutamate transmission in the brain. The treatment may be delivered as standalone ketamine infusions in medical clinics or as ketamine-assisted psychotherapy (KAP), where therapeutic support is integrated before, during, and after dosing sessions to maximize psychological integration and durability of effects.
Origins & Lineage
Ketamine was first synthesized in 1962 by Dr. Calvin Stevens, a chemistry consultant working with Parke-Davis Pharmaceuticals at Wayne State University. The original goal was a better anesthetic with fewer of the psychiatric side effects of phencyclidine (PCP). Ketamine received FDA approval as Ketalar in 1970. By the time it did, the U.S. military had already been using it extensively in Vietnam. It was used extensively during the Vietnam War as an anesthetic agent due to its ease of administration and safety profile.
By the late 1970s, ketamine was used in underground psychedelic therapy, with some researchers exploring its mental health potential while others warned of its hallucinogenic risks. During the 1990s, ketamine became a popular party drug, known as “Special K,” for its dissociative and euphoric effects. Despite increased recreational use and stricter regulation, clinical research into ketamine’s psychiatric applications continued.
In 2000, a team at Yale School of Medicine published the first randomized controlled trial to demonstrate ketamine’s antidepressant effects. In the 2000s, studies began to emerge highlighting ketamine’s rapid antidepressant effects, producing significant improvements in depressive symptoms within hours. This research marked the beginning of ketamine’s reemergence as a psychiatric treatment tool.
On March 5, 2019, the U.S. Food and Drug Administration (FDA) approved SPRAVATO (esketamine) nasal spray in conjunction with an oral antidepressant for the treatment of treatment-resistant depression (TRD) in adults. Esketamine, the S-enantiomer of ketamine, is the only FDA-approved form of ketamine for psychiatric use. Racemic ketamine itself remains off-label for mental health treatment, though widely prescribed by clinicians.
How It’s Practiced
Ketamine therapy takes two primary forms: ketamine infusion therapy and ketamine-assisted psychotherapy (KAP).
Ketamine Infusion Therapy: In these clinics, clients are typically given a series of IV infusions several times a week and are not necessarily engaged in any formal psychotherapy. Sessions generally last 40-60 minutes and patients are monitored in a clinical setting. While helpful for acute symptoms such as suicidality, when ketamine infusions are given without therapeutic support, the neuroplastic benefits may be minimized. Patients often recline in a treatment chair with eye masks and listen to music during the dissociative experience.
Ketamine-Assisted Psychotherapy (KAP): Ketamine-assisted psychotherapy is therapy-centered: the medicine is one tool inside a treatment relationship rather than the treatment itself. The number of sessions needed depends on individual goals and progress but our protocol will include one or two preparation sessions, four dosing sessions, and ongoing integration sessions. Administration of KAP is usually sublingual, using rapid dissolvable tablets or lozenges/troches, or intramuscular (injected into the deltoid muscle). KAP is psychotherapy-centered: I provide preparation before each session, therapeutic support during the ketamine experience, and integration therapy afterward.
During dosing sessions, patients typically experience dissociation—a state of detachment from ordinary reality—alongside potential mystical or introspective experiences. During ketamine treatment, people report sudden clarity, awe, or profound understanding. As the grip on habitual thought patterns softens and the sense of the physical body fades, people can achieve a new perspective about pre-existing issues.
Ketamine Therapy Today
Currently only 20% of the 2,500 ketamine clinics in the United States offer ketamine-assisted psychotherapy. Most ketamine clinics focus exclusively on infusion protocols for treatment-resistant depression and acute suicidality. The FDA approved an esketamine nasal spray (Spravato) for treatment-resistant depression in 2019, and clinical practice guidelines from the American Psychiatric Association include ketamine and esketamine as recommended options for treatment-resistant depression.
Ketamine is used off-label for depression, anxiety, PTSD, OCD, chronic pain, and addiction treatment. A substantial body of peer-reviewed research evaluates ketamine as a treatment for depression, anxiety, PTSD, and other mental health conditions, published across leading academic and clinical research institutions in the U.S. and internationally. Research continues to explore its role in addressing addiction, end-of-life distress, and other psychiatric conditions.
Beyond clinical psychiatry, ketamine therapy has gained attention in consciousness and spiritual communities. Research supports what many already intuit: a mystical experience during treatment often correlates with better outcomes. This trial adds evidence to the literature on the importance of mystical-type experiences in addiction treatment. Some practitioners integrate ketamine into trauma work, somatic therapy, and spiritual inquiry frameworks.
Common Misconceptions
Ketamine therapy is not a cure or permanent fix. KAP produced sustained reductions in anxiety, depression, and PTSD, with symptom improvement lasting well beyond the duration of dosing and integration sessions. These effects extended to as much as 5 months after the last KAP session. Many patients require ongoing maintenance sessions to sustain benefits.
Ketamine is not the same as esketamine (Spravato). Though esketamine is derived from racemic ketamine, they are not the same drug. Racemic ketamine—the form used in most clinics—is prescribed off-label; esketamine nasal spray is the only FDA-approved psychiatric formulation.
Ketamine therapy is not recreational use. Therapeutic dosing is sub-anesthetic and administered in supervised clinical environments with medical oversight. Esketamine is available only through certified physicians’ offices or clinics under a Risk Evaluation and Mitigation Strategy (REMS) program, because of the risk for serious adverse outcomes resulting from sedation and dissociation caused by esketamine treatment and the potential for abuse and misuse.
It is not a standalone treatment for all psychiatric conditions. The strongest evidence base, and the use case most people come in describing, is treatment-resistant depression. Ketamine is most effective for individuals who have not responded to multiple prior treatments.
Mystical experiences are not required for therapeutic benefit. Some studies suggest strong mystical experiences increase the number of people who respond positively to ketamine, while other research shows little impact on initial response rates. While some patients report profound spiritual or transcendent states, clinical outcomes do not depend on such experiences.
How to Begin
Individuals considering ketamine therapy should first consult with a psychiatrist or mental health provider experienced in psychedelic-assisted treatments. A thorough psychiatric evaluation is required to determine appropriateness, as ketamine is contraindicated for certain conditions such as uncontrolled hypertension, psychosis, or active substance use disorders.
If pursuing ketamine infusion therapy, research licensed medical clinics that specialize in IV ketamine for depression. Verify that physicians are trained in ketamine administration and that monitoring protocols are in place.
For ketamine-assisted psychotherapy, seek therapists certified through organizations such as the Psychedelic Research and Training Institute (PRATI), Polaris Insight Center, or the American Society of Ketamine Physicians, Psychotherapists, and Practitioners (ASKP3). These therapists work in partnership with prescribing medical providers.
Books such as The Ketamine Papers edited by Phil Wolfson and Glenn Hartelius (2016) and Psychedelic Medicine by Dr. Richard Louis Miller (2017) provide historical and clinical context. Online platforms like Psychedelic.Support and the Multidisciplinary Association for Psychedelic Studies (MAPS) offer directories of qualified practitioners.
Ensure financial clarity before beginning treatment, as most insurance does not cover off-label ketamine therapy. Esketamine (Spravato) may be covered for treatment-resistant depression under specific conditions.