Most antidepressants work by adjusting chemical levels — ketamine works by physically rebuilding the brain’s communication infrastructure. For patients with treatment-resistant depression who have cycled through medications without lasting relief, this distinction matters enormously. At InfuseRVA Ketamine & Wellness in South Chesterfield, Virginia, we offer IV ketamine infusion therapy because the science behind how it works is unlike anything that came before it.
What Happens in a Brain with Treatment-Resistant Depression
To understand what ketamine does, it helps to understand what depression does first. Treatment-resistant depression — a clinical designation for major depressive disorder that has not responded adequately to two or more antidepressant trials at therapeutic doses — is not simply a serotonin deficiency. Research has shown that in many patients with this condition, the glutamate system (the brain’s primary excitatory neurotransmitter network) is dysregulated, and the physical architecture of the brain’s neural pathways is compromised (Kim et al., 2022).
Specifically, prolonged depression is associated with reduced synaptic density — fewer and weaker connections between neurons in regions like the prefrontal cortex and hippocampus, areas responsible for mood regulation, decision-making, and emotional processing. The brain, in a sense, loses some of its structural capacity to process and regulate emotional experience. This is why patients often describe depression not just as sadness, but as a flattening, a cognitive fog, an inability to feel anything at all. The underlying biology reflects exactly that: a brain with fewer functioning pathways.
Conventional antidepressants, which primarily target serotonin and norepinephrine, do not directly address glutamate system dysregulation or synaptic loss. For patients with treatment-resistant depression, this is precisely why those medications may have fallen short.
How Ketamine Acts on the Glutamate System
Ketamine is an NMDA receptor antagonist — meaning it works by temporarily blocking a specific type of glutamate receptor called the N-methyl-D-aspartate receptor. This sets off a cascade of events in the brain that unfolds differently from anything conventional antidepressants produce.
When ketamine blocks NMDA receptors on inhibitory neurons called GABAergic interneurons, it triggers a surge of glutamate release in the prefrontal cortex. That glutamate surge activates a different type of receptor — the AMPA receptor — which then initiates a series of intracellular signaling events involving two key molecular pathways: the mTOR pathway (mechanistic target of rapamycin) and BDNF-TrkB signaling. BDNF stands for brain-derived neurotrophic factor, a protein that supports the growth, survival, and maintenance of neurons. The mTOR pathway regulates protein synthesis inside cells (Kim et al., 2022).
Together, these pathways drive synaptogenesis — the formation of new synaptic connections — and promote the growth of new dendritic spines, the structures neurons use to receive signals from neighboring cells. In practical terms, ketamine may actively help the brain rebuild some of the neural architecture that depression eroded. This is the foundation of what researchers mean when they discuss ketamine’s neuroplastic effects.
Ketamine also acts simultaneously at the postsynaptic level. When NMDA receptors at rest are antagonized, a specific enzyme called eEF2 kinase is deactivated. That enzyme normally suppresses BDNF production. By removing that suppression, ketamine creates a second mechanism — independent of AMPA receptor activation — by which BDNF levels rise and neuroplasticity is enhanced (Kim et al., 2022). These dual pathways working in parallel are part of why ketamine’s effects can be both rapid and, for many patients, more sustained than a single neurotransmitter adjustment.
Brain Network Changes Observed in Research
The effects of ketamine are not limited to the molecular level. Neuroimaging research has documented measurable changes in how entire brain networks function following ketamine administration. The Default Mode Network, the Central Executive Network, and the Salience Network — three interconnected systems involved in self-referential thinking, cognitive control, and the prioritization of emotional stimuli — are all frequently disrupted in patients with depression. Studies using functional neuroimaging have demonstrated that ketamine produces alterations in the activity and connectivity of these networks (Kadriu et al., 2024).
This is meaningful for patients who have wondered whether their depression would ever respond to anything. The changes visible on neuroimaging are not subjective — they reflect measurable reorganization of brain function. For many patients with treatment-resistant conditions, this represents a genuinely different category of treatment than anything they may have tried previously. To learn more about the range of conditions we address, visit our conditions page.
What This Means at the Clinical Level
The neuroplastic and network-level effects of ketamine translate into something that patients and their families often find striking: speed. Where traditional antidepressants can take four to eight weeks to produce noticeable effects — if they produce them at all — many patients receiving IV ketamine infusion therapy report mood improvements within hours to days of their first treatment. This rapid onset is directly connected to the mechanism described above. Synaptogenesis and BDNF elevation can occur quickly once the glutamate cascade is initiated; the brain does not need weeks to synthesize new receptors the way it does with serotonin-targeted medications.
At InfuseRVA, we administer ketamine intravenously, which provides the most consistent bioavailability and the most direct route to the neurological effects described here. Our standard approach involves a series of six infusions, each lasting approximately 40 to 60 minutes, with each patient evaluated by our medical team before beginning treatment. Because ketamine’s effects vary by individual — and because pre-existing conditions, current medications, and personal history all affect how a patient responds — we conduct a thorough evaluation before any treatment begins. We also strongly recommend that patients maintain a relationship with a therapist throughout their treatment course. The neuroplastic window that ketamine may open — a period of heightened synaptic flexibility — can be a meaningful opportunity to reinforce new thought patterns and coping strategies through psychotherapy.
We also offer ketamine-assisted psychotherapy for patients who want to integrate therapeutic work directly into their treatment. For patients who qualify for FDA-approved esketamine therapy, we offer SPRAVATO® treatment as well. SPRAVATO® is FDA-approved specifically for treatment-resistant depression and for major depressive disorder with acute suicidal ideation or behavior; it is administered as a nasal spray in our office under direct supervision and is not the same formulation as IV ketamine.
Addressing Common Concerns About Pursuing Ketamine Therapy
One of the biggest barriers patients face is uncertainty about whether they are a candidate. Ketamine is not appropriate for everyone. Patients with certain cardiovascular conditions, active psychotic symptoms, or histories of substance use disorder may not be suitable candidates, and our evaluation process is designed to identify those factors early. The goal of that evaluation is not gatekeeping — it is ensuring that the patients we treat are the patients most likely to benefit, and that we can do so safely. Results vary by individual, and we never make promises about outcomes. What we can offer is a careful, personalized assessment that takes your full history seriously. If you have questions before committing to an evaluation, our ketamine infusion FAQs cover many of the most common concerns in detail.
Frequently Asked Questions
Is ketamine the same medication used in anesthesia? Yes — ketamine has been used safely as an anesthetic in medical settings for more than 60 years. At the sub-anesthetic doses used in psychiatric treatment, it produces a dissociative experience rather than full sedation, and the neurological effects on mood and neuroplasticity occur at a fundamentally different dose range than its anesthetic use. Medical supervision throughout every infusion is standard at our clinic.
How long do the neurological benefits of ketamine last? The duration of response varies considerably from patient to patient. Some individuals maintain improvements for weeks to months after a series of infusions; others may benefit from periodic maintenance treatments. Research on long-term maintenance protocols is ongoing, and we discuss what follow-up care may look like based on each patient’s individual response.
Does ketamine work differently for chronic pain than for depression? Ketamine’s NMDA receptor antagonism also affects pain pathways, which is why it may be helpful for certain chronic pain conditions. The mechanism overlaps with but is not identical to its antidepressant effects. Patients with both a mood disorder and a chronic pain condition may find that ketamine addresses both simultaneously, though responses vary and we evaluate each patient’s specific situation before recommending a course of treatment.
Do I need a referral to be evaluated at InfuseRVA? No referral is required. We ask that you bring documentation of your diagnoses, treatment history, current medications, and any adverse reactions to prior treatments. We do recommend informing your current physician or therapist about your plans to begin ketamine therapy before your first infusion.
What happens if I do not respond after the initial series? Not all patients respond to ketamine, and our evaluation continues throughout treatment. If you do not show a meaningful response, we will discuss that honestly and help you think through what options remain. We do not pressure patients to continue treatment that does not appear to be working, and we do not guarantee outcomes for any individual.
Key Takeaways
- Ketamine works through the glutamate system rather than serotonin, making it a mechanistically distinct option for patients whose depression has not responded to conventional antidepressants.
- Its neuroplastic effects — including increased BDNF production, mTOR activation, and new synapse formation — may help rebuild the neural architecture compromised by chronic depression.
- Neuroimaging research has documented measurable changes in key brain networks involved in mood regulation following ketamine treatment.
- Mood improvements may occur within hours to days, rather than the weeks required by traditional antidepressants.
- Results vary by individual; thorough medical evaluation before treatment and ongoing monitoring are essential to safe and appropriate use.
The brain changes that depression produces are real, and the changes that ketamine may produce in response are equally real. If you have worked through multiple medications without finding relief and are looking for a treatment grounded in a different kind of science, we encourage you to reach out to our team at InfuseRVA. Call us at804-895-4636 or contact us to schedule a consultation — your history matters, and we want to hear it before we recommend anything.
References
Kadriu, B., Musazzi, L., Johnston, J.N.K., Kalynchuk, L.E., Caruncho, H.J., & Bhatt, S. (2024). Beyond NMDA receptors: A narrative review of ketamine’s rapid and multifaceted mechanisms in depression treatment. International Journal of Molecular Sciences, 25(24), 13658. https://pmc.ncbi.nlm.nih.gov/articles/PMC11728282/
Kim, M.J.Y., Hebert, E.R., Villanueva, M., Bhatt, D.L., & Monteggia, L.M. (2022). The mechanisms behind rapid antidepressant effects of ketamine: A systematic review with a focus on molecular neuroplasticity. Frontiers in Psychiatry, 13, 860882. https://pmc.ncbi.nlm.nih.gov/articles/PMC9082546/
Jiang, M., Wang, M.H., & Bhatt, D.L. (2023). Antidepressant mechanisms of ketamine: A review of actions with relevance to treatment-resistance and neuroprogression. Frontiers in Neuroscience, 17, 1223145. https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2023.1223145/full
Medical Disclaimer
The information in this blog is for educational purposes only and does not constitute medical advice. IV ketamine infusion therapy and SPRAVATO® treatment should only be pursued under the supervision of a licensed medical professional familiar with your complete medical and psychiatric history. Individual results vary. Not all patients are candidates for ketamine therapy. If you are experiencing a mental health crisis or thoughts of self-harm, please call or text 988 to reach the Suicide and Crisis Lifeline or go to your nearest emergency room.
