Talking Ketamine Podcast

For anyone struggling with treatment-resistant depression (TRD), starting ketamine therapy represents a major investment of time, money, and emotional hope. In this episode, we tackle the ultimate question: is there a way to predict if ketamine will actually work for you before you commit? We explore the groundbreaking research of Omer Ahmed Syed from the University of Toronto, which pairs a systematic review of 112 clinical studies spanning two decades with a real-world retrospective analysis of 77 patients receiving repeated intravenous (IV) ketamine infusions. The baseline results are highly encouraging, showing that over half (50.6%) of these difficult-to-treat patients achieved a full response, with another 22.1% experiencing a partial response.

Spotting the early signs of success turns out to be surprisingly simple. By tracking symptom scores infusion by infusion, researchers identified a clear split between future responders and non-responders after just the second dose. The key early warning signal is a mere 4.1% reduction on the standard Patient Health Questionnaire-9 (PHQ-9) scale. While a 4% improvement might feel barely noticeable to the patient, this tiny drop acts as a perfect positive predictor (PPV of 1.0)—meaning every single patient who hit this threshold went on to achieve a successful treatment outcome. Like the first slow turn of a massive ship, this minor drop signals that the biological mechanism has been successfully engaged, even if the person cannot feel the full turn yet. Conversely, the hosts emphasize that early non-improvement does not mean failure; nearly half (47.5%) of the patients who showed zero improvement after dose two still achieved a full or partial response by the end of the course, making a strong case for sticking with the protocol.

When it comes to predicting success before treatment even begins, the study successfully busts several common clinical myths. Demographic factors like age and sex, as well as baseline depression severity, anxiety, trauma history (such as adverse childhood experiences or PTSD), and even the intensity of dissociation experienced during the infusion, had no significant association with the final antidepressant outcome. However, a major headwind emerged: a history of failed oral antidepressants. Patients who had tried and failed more than six different medications in their lifetime were 78% less likely to respond to ketamine, suggesting a pharmacological "line in the sand." Interestingly, a history of neuromodulation therapies like ECT or TMS did not affect the odds, indicating that this resistance is drug-specific. This clinical boundary suggests that ketamine should be considered much earlier in the treatment timeline, before patients cycle through a long list of ineffective medications and endure unnecessary cognitive burdens.

Resources:

Syed, O. A., Sobolenko, V., Nestor, S. M., Husain, M. I., Lipsman, N., Alam, F., & Giacobbe, P. (2026). Clinical Predictors of Antidepressant Effects of Ketamine and Esketamine in Treatment-Resistant Unipolar and Bipolar Depression: A Systematic Review. CNS Drugs. Advance online publication. https://doi.org/10.1007/s40263-026-01296-7

(Note: The above journal citation represents the peer-reviewed publication of the systematic review from Chapter 4 of the thesis. The full Master's thesis containing the secondary 77-patient retrospective analysis is cited as: Syed, O. A. (2025). Predictors of the antidepressant effects of ketamine and psychedelic substances (Master's thesis, University of Toronto). TSpace. https://hdl.handle.net/1807/146039)

Undergoing surgery is a massive physiological trauma. Beyond the immediate incision, patients must navigate a gauntlet of bodily stress, anesthesia side effects, and hospital disruptions that frequently trigger postoperative sleep disturbance (PSD)—a condition affecting up to 72% of patients. For those already struggling with sleep before entering the operating room (identified by a score greater than five on the Pittsburgh Sleep Quality Index), surgery can be the tipping point that leads to delirium, heightened pain, and cognitive decline. In this episode, we unpack a clinical trial involving 130 high-risk patients that demonstrated how a continuous, subanesthetic infusion of esketamine during surgery can act as a powerful shield. On the first day after surgery, the esketamine group experienced a dramatic drop in sleep disturbances (falling from 65% to 43%), reported less pain, and required significantly fewer heavy opioid painkillers like hydromorphone.

While esketamine's clinical success is impressive, the study's most surprising discovery came from saliva samples. The mouth serves as the second most diverse microbial community in the human body, acting as a sensitive barometer for systemic stress. When this ecosystem falls into a state of imbalance, known as dysbiosis, it can trigger neuropsychiatric and sleep disorders. The researchers found that esketamine actively reshaped the oral microbiome, promoting beneficial genera like Streptococcus and Peptostreptococcus while suppressing Bacteroidota. Conversely, patients who suffered from poor sleep and severe pain showed higher levels of Haemophilus and Neisseria. This microbial protection was particularly pronounced in patients aged 50 to 65, the very demographic most vulnerable to postoperative complications.

How does an intravenous anesthetic target bacteria living in the mouth? The answer lies in systemic ecology. Surgery ignites an immunological wildfire, flooding the body with pro-inflammatory cytokines. Esketamine acts as a powerful anti-inflammatory that tempers this systemic fire. Rather than acting as a direct disinfectant, it alters the host environment—essentially "changing the soil so different plants can grow," making the body less hospitable to stress-related microbes. Furthermore, the gut-oral axis reveals that these ecosystems are not isolated islands. As esketamine stabilizes the gut microbiome, the benefits ripple up the nervous and immune pathways to the oral cavity. Ultimately, esketamine's therapeutic power is ecological, restoring balance to our nerves, immune cells, and microbial partners alike.

Resources:

Li, X.-Y., Qiu, D., Du, N., Hashimoto, K., Wang, X.-M., & Yang, J.-J. (2025). Esketamine prevents postoperative sleep disturbance in patients with preoperative sleep disorders: A role for oral microbiota. Translational Psychiatry, 15, 501. https://doi.org/10.1038/s41398-025-03705-9

Catatonia is often misunderstood as simple immobility, but it is a terrifying, life-threatening syndrome of stupor, mutism, and extreme negativism—a state where the brain is essentially “frozen.” For decades, the standard protocol has been to step on the “brake pedal” using GABA-ergic drugs like lorazepam, followed by Electroconvulsive Therapy (ECT) if medication fails. But what happens when the brakes don’t work, and ECT is medically unsafe or unavailable?

This episode analyzes a new systematic review of 10 unique case reports that suggests NMDA receptor antagonists like ketamine and esketamine could be the “skeleton key” for these desperate scenarios. We explore the neurochemistry of switching from the failed inhibitory (GABA) pathway to directly targeting the excitatory (Glutamate) system. The theory? Refractory catatonia may be driven by a massive glutamate hypo-function—the brain’s engine isn’t firing—and ketamine triggers the necessary surge to reset the circuit.

The clinical results discussed are striking: 100% of the patients in the review showed symptom improvement, often within hours to days. We also debunk the common fear that ketamine might destabilize these fragile patients by triggering mania or psychosis; the review found these risks were not supported by the data. Finally, we highlight the practical game-changer of intranasal esketamine, which allows clinicians to bypass the resistance often seen in mute, withdrawn patients who cannot swallow pills.

Reference:

van der Meer, P. B., Verboeket, S., Slooter, A. J. C., Schoones, J. W., van Noorden, M. S., Somers, M., Batalla, A., & Dols, A. (2025). Treatment with (es)ketamine in catatonia: A systematic review of case reports. The Journal of Clinical Psychiatry, 86(4), Article 25br15940. https://doi.org/10.4088/JCP.25br15940

Catatonia is often misunderstood as simple immobility, but it is a terrifying, life-threatening syndrome of stupor, mutism, and extreme negativism—a state where the brain is essentially “frozen.” For decades, the standard protocol has been to step on the “brake pedal” using GABA-ergic drugs like lorazepam, followed by Electroconvulsive Therapy (ECT) if medication fails. But what happens when the brakes don’t work, and ECT is medically unsafe or unavailable?

This episode analyzes a new systematic review of 10 unique case reports that suggests NMDA receptor antagonists like ketamine and esketamine could be the “skeleton key” for these desperate scenarios. We explore the neurochemistry of switching from the failed inhibitory (GABA) pathway to directly targeting the excitatory (Glutamate) system. The theory? Refractory catatonia may be driven by a massive glutamate hypo-function—the brain’s engine isn’t firing—and ketamine triggers the necessary surge to reset the circuit.

The clinical results discussed are striking: 100% of the patients in the review showed symptom improvement, often within hours to days. We also debunk the common fear that ketamine might destabilize these fragile patients by triggering mania or psychosis; the review found these risks were not supported by the data. Finally, we highlight the practical game-changer of intranasal esketamine, which allows clinicians to bypass the resistance often seen in mute, withdrawn patients who cannot swallow pills.

Reference:

van der Meer, P. B., Verboeket, S., Slooter, A. J. C., Schoones, J. W., van Noorden, M. S., Somers, M., Batalla, A., & Dols, A. (2025). Treatment with (es)ketamine in catatonia: A systematic review of case reports. The Journal of Clinical Psychiatry, 86(4), Article 25br15940. https://doi.org/10.4088/JCP.25br15940

The post Ketamine for Catatonia appeared first on Talking Ketamine Podcast.

We move beyond depression and anesthesia to examine ketamine’s role in fighting one of the most severe types of chronic pain imaginable: Complex Regional Pain Syndrome (CRPS). This condition is marked by wildly disproportionate and persistent pain , exemplified by the case of a 15-year-old athlete whose simple hand fracture healed, but whose nervous system got stuck in a pathological pain loop.

The core problem in CRPS is central sensitization—the brain and spinal cord jamming the “volume knob” for pain on maximum, where a light touch (allodynia) is interpreted as excruciating.

Traditional treatments fail because the problem is upstream, residing in the central nervous system (CNS). Specialists employed a clever, multimodal strategy to finally break this refractory pain cycle:

* Gabapentin: To calm general static in the nervous system.

* Continuous Nerve Block: A regional anesthetic to temporarily silence all incoming peripheral pain signals from the arm.

* Continuous Ketamine Infusion: The NMDA receptor antagonist was the core component, performing a “software reboot” on the CNS. Ketamine acts as a master switch, physically blocking the NMDA receptor that powers the central sensitization system, thereby interrupting the vicious wind-up cycle.

The results were dramatic: pain, which was agonizing, dropped from 7/10 to 2/10 within 24 hours, resolving completely in 48 hours. Allodynia resolved, enabling the essential physiotherapy needed for long-term recovery. This case report is a powerful demonstration of ketamine’s versatility, showing it can act not just as a painkiller, but as a system reset for neurological conditions rooted in faulty learning.

Reference:

Medikondu, H., Davit, A., & Visoiu, M. (2025). Effective Adolescent Hand CRPS Type 1 Treatment Using Ketamine, Gabapentin, and Supraclavicular Nerve Block Catheter. Preprints.org. https://doi.org/10.20944/preprints202511.0755.v1

Chronic mental illnesses like severe MDD (major depressive disorder) and PTSD are alarms, not just for the mind, but for the body. This episode explores the fact that ongoing trauma and depression accelerate biological aging, leading to reduced health span and higher risks for chronic diseases. But can rapid, effective psychiatric treatment actually reverse this damage?

We dive into a compelling pilot study that gave a series of six sub-anesthetic ketamine infusions to 20 participants with treatment-resistant depression or PTSD. The researchers used second-generation epigenetic clocks to measure biological age—the actual cellular wear and tear, separate from chronological age. The most advanced clock used, OMICs-AGE, integrates DNA methylation with surrogates for over 40 proteins, metabolites, and clinical markers across eight physiological systems, showing the strongest link to mortality risk.

The findings are potentially groundbreaking:

* Age Reversal: The study found a clear, statistically significant reduction in epigenetic age across several markers after treatment. Critically, the signal captured by OMICs-AGE held up under stringent statistical correction, suggesting a genuine biological age deceleration.

* The Mechanism: This reversal is linked to specific anti-aging pathways. Ketamine treatment led to a significant reduction in CD4 T memory cells, which are markers for systemic inflammation and aging (immunosenescence). Further analysis revealed shifts in metabolic and neuroimmune markers clustered around circadian sleep regulation and T-cell differentiation.

While this was a small pilot study without a non-treatment control group , the robustness of the OMICs-AGE signal suggests a profound implication: the ultimate longevity treatment may lie not in anti-aging creams, but in aggressively treating the mental illness that accelerates the biological clock in the first place. Mental health truly is longevity health.

Reference:

Dawson, K. L., Carangan, A. M. J. M., Klunder, J., Carreras-Gallo, N., Sehgal, R., Megilligan, S., Askins, B. C., Mendez, T. L., Smith, R. M., Dawson, M. S., Mallin, M. P., Higgins-Chen, A. T., & Dwaraka, V. B. (2025). Epigenetic aging and DNA methylation biomarker changes following ketamine treatment in patients with MDD and PTSD: a pilot study. Translational Psychiatry, 15(1), 452. https://doi.org/10.1038/s41398-025-03683-y

The KARMA-Dep2 trial delivered a shocking headline: up to eight serial ketamine infusions were no better than the midazolam placebo for hospitalized adults with moderate to severe depression. In an era of intense hope for ketamine’s rapid antidepressant effects, this result demands a closer look.

This episode critically dissects why this large, pragmatic trial may have failed to show a significant difference, focusing on a central challenge in ketamine research: blinding.

* The Active Placebo Problem: The trial used midazolam as an active placebo to mimic the transient side effects (like sedation and disorientation) of ketamine. However, previous meta-analyses (Wilkinson et al., 2019) show that midazolam itself produces a substantial placebo/expectancy effect (around an 18% response rate), effectively setting a high floor that makes the pharmacological benefit of ketamine harder to detect.

* The Unblinding Issue: We contrast the KARMA-Dep2 outcome with the Dwyer et al. (2021) adolescent trial, where ketamine was significantly better than midazolam. Crucially, the adolescent study revealed a massive confound: 10 out of 10 patients on ketamine correctly guessed their treatment, illustrating the “functional unblinding” that allows expectation to heavily influence results.

* The Measurement Challenge: We discuss the inherent difficulty of using scales designed for slow-acting drugs (like MADRS and HAMD) to measure ketamine’s rapid antidepressant effects, leading to measurement workarounds like carrying over scores for symptoms like sleep and appetite.

The core question remains: Does midazolam give a truly realistic estimate of ketamine’s effect, or does chasing the “perfect blind” with an active placebo simply obscure the real-world value of a drug whose unique, powerful experience is inseparable from its clinical benefit?

Resources:

Wilkinson, S. T., Farmer, C., Ballard, E. D., Mathew, S. J., Grunebaum, M. F., Murrough, J. W., Sos, P., Wang, G., Gueorguieva, R., & Zarate, C. A., Jr. (2019). Impact of midazolam vs. saline on effect size estimates in controlled trials of ketamine as a rapid-acting antidepressant. Neuropsychopharmacology, 44, 1233–1238. https://doi.org/10.1038/s41386-019-0317-8

Dwyer, J. B., Landeros-Weisenberger, A., Johnson, J. A., Londono Tobon, A., Flores, J. M., Nasir, M., Couloures, K., Sanacora, G., & Bloch, M. H. (2021). Efficacy of Intravenous Ketamine in Adolescent Treatment-Resistant Depression: A Randomized Midazolam-Controlled Trial. American Journal of Psychiatry, 178(4), 352–362. https://doi.org/10.1176/appi.ajp.2020.20010018

Jelovac, A., McCaffrey, C., Terao, M., Shanahan, E., Whooley, E., McDonagh, K., McDonogh, S., Loughran, O., Shackleton, E., Igoe, A., Thompson, S., Mohamed, E., Nguyen, D., O’Neill, C., Walsh, C., & McLoughlin, D. M. (2025). Serial Ketamine Infusions as Adjunctive Therapy to Inpatient Care for Depression: The KARMA-Dep 2 Randomized Clinical Trial. JAMA Psychiatry. https://doi.org/10.1001/jamapsychiatry.2025.3019

For years, the most recognized physical risk of chronic ketamine abuse has been bladder damage, but a new clinical puzzle is emerging: severe injury to the liver and bile ducts, known as Ketamine-induced Sclerosing Cholangitis (K-SC). This episode dives into a recent case series detailing patients—including older and female European users—broadening the picture of who is at risk.

Sclerosing cholangitis is a progressive condition where chronic inflammation leads to severe scarring and narrowing of the bile ducts. This obstruction causes bile backup (cholestasis), which, if unchecked, can result in irreversible cirrhosis—often making a liver transplant the only option. We explain why laboratory markers like GGT and ALP are critical red flags for this damage.

How does this anesthetic target the liver’s plumbing? The leading hypothesis suggests chronic, high-dose exposure over time causes sustained spasms due to ketamine’s effect on NMDA receptors located in the bile duct smooth muscle. Crucially, the severity of this liver damage often tracks directly with the severity of a patient’s urinary symptoms, suggesting a systemic toxic effect on similar smooth muscle tissues in both the bladder and the biliary system.

Using diagnostic criteria, physicians confirmed K-SC by ruling out other look-alike conditions (like PSC, which is tied to IBD). The strongest evidence linking the drug to the severe damage was the dramatic clinical improvement in lab results immediately after patients ceased ketamine use.

The main takeaway for anyone concerned is non-negotiable: the absolute first line of defense is immediate and permanent cessation of all ketamine use. Management requires a comprehensive multidisciplinary team—gastroenterologists, urologists, and addiction specialists—to manage the devastating progression and provide essential addiction support. This exploration underscores a tragic potential consequence of long-term abuse and the urgent need for more longitudinal research.

Resources:

Vanrusselt, A., Nijs, J., Van den Bergh, L., Schoofs, N., Smets, S., Strybol, D., & Rappaport, A. (2025). Ketamine-induced sclerosing cholangitis: a case series. Acta Gastro-Enterologica Belgica, 88(3), 271–276. https://doi.org/10.51821/88.3.13914

This episode breaks down a truly radical theory of consciousness: The General Resonance Theory (GRT). Forget the traditional idea that consciousness comes from synapses firing—GRT proposes that it emerges from near-instantaneous, resonant electromagnetic field interactions within the brain, moving information up to 40,000 times faster than slow neuronal spikes. This electrical “field” is the true substrate of our unified sense of reality.

We use this theory to answer the biggest question in psychedelic science: Why does ketamine cause dissociation? While classic psychedelics are seen as “field resonance enhancers” that create feelings of unity and global synchronization, ketamine does the precise opposite. We reveal the precise mechanism: ketamine preferentially removes the “brakes” (NMDA receptors on inhibitory GABA neurons). This results in fragmented hyperactivity. Local circuits go wild, but they lose the coherence needed for a unified sense of self, leading to the subjective experience of dissociation and the ultimate breakdown of integrated consciousness—the K-hole.

Electrically, this shows up as a measurable decoupling between the frontal and parietal regions, the key areas for self and spatial awareness. Finally, we explore the provocative idea that ketamine’s rapid antidepressant effect might be due to this temporary, total electromagnetic reset—a complete shaking of the “snow globe” that forces the brain’s rigid, unhealthy field patterns to resettle into a more flexible configuration. This is mind-bending physics that reframes mental health treatment as an exercise in tuning the brain’s frequency.

Reference:

Hunt, T. (2025). Electrodynamics of the Psychedelic Experience. Preprints.org. https://doi.org/10.20944/preprints202509.1813.v1

When stroke strikes, the damage doesn’t stop once the blood flow is restored. This episode dives into the dark side of recovery: the Ischemia-Reperfusion (IR) Injury, a devastating “second wave” of damage that causes lasting neurological deficits.

We explore a fascinating preclinical study on esketamine, the S-enantiomer of ketamine. Researchers hypothesized that this powerful NMDA receptor antagonist could stop IR injury, which is fueled by excessive excitotoxicity. We reveal how esketamine, when administered immediately after blood flow is restored, actively helps the brain fight back.

The findings are compelling: esketamine significantly reduced markers of cell membrane damage (MDA) and, crucially, bolstered the brain’s own antioxidant defense system in the vulnerable hippocampal CA1 region. This dose-dependent effect points toward a new therapeutic window, allowing intervention hours or even days after a clot is removed. Could ketamine be the neuroprotectant that finally helps save the tissue we just rescued?

Tune in to understand the science behind this potential breakthrough and the challenge of finding the neuroprotective ‘sweet spot’ dose.

Reference:

Erfani, S., Amirhaidari, B., & Khoshnazar, S. M. (2025). Antioxidant Therapeutic Potential of S-Ketamin Against Cerebral Ischemia/Reperfusion Injury in Male Rats. Journal of Isfahan Medical School, 43(821), 749–758. https://doi.org/10.48305/jims.v43.i821.0749