Knowledge Tree
ketamine
synthesized from dimensionsKetamine is a synthetic, dissociative pharmacological agent originally developed as an anesthetic [fact:28|Ketamine and phencyclidine (PCP) are synthetic drugs], [fact:29|Ketamine and phencyclidine (PCP) were initially employed as anaesthetics]. In contemporary medicine, it has emerged as a significant, albeit complex, tool in psychiatry, recognized as the only NMDA antagonist currently approved for medical treatment [fact:55|Ketamine is currently the only NMDA antagonist recognized as a medical treatment]. It is increasingly utilized as a rapid-acting intervention for treatment-resistant depression (TRD) and is actively researched for its potential to mitigate suicidality and address 'diseases of despair,' including substance use disorders [fact:14|Modern medical researchers are investigating psychedelic compounds], [fact:15|Proponents of psychedelic-assisted therapy suggest that compounds like MDMA, LSD, psilocybin, and ketamine may help alter the perspectives of individuals suffering from 'diseases of despair'].
The therapeutic profile of ketamine is fundamentally linked to its role as a 'psychoplastogen'—a substance capable of promoting neuroplasticity Neuroplasticity as a convergent mechanism. Mechanistically, it modulates glutamatergic N-Methyl-D-Aspartate (NMDA) receptors [fact:18|Ketamine acts on glutamatergic N-Methyl-D-Aspartate receptors] and enhances brain-derived neurotrophic factor (BDNF) levels, which facilitates synaptogenesis and neurite growth [fact:33|Ketamine increases BDNF levels], [fact:35|Ketamine enhances synaptogenesis and neurite growth in young adult mice]. Additional research into its neurobiological impact highlights its influence on AMPA receptors, mTOR signaling Ketamine enhances structural plasticity, and the inhibition of stress-induced dendritic spine elimination.
Clinical application of ketamine has diverged into two primary frameworks: the biomedical approach and the psychedelic-assisted approach Research has diverged into two bodies. The biomedical model focuses on standardized pharmacological protocols—such as the 0.5 mg/kg intravenous infusion—often treating the drug's psychoactive effects as secondary or irrelevant to its antidepressant efficacy 0.5 mg per kg dosing protocol, Biomedical view of ketamine treatment. In contrast, integrative models, such as the 'Montreal model,' incorporate ketamine into a broader biopsychosocial intervention Montreal model integrates ketamine into therapy. These models emphasize the importance of the therapeutic 'frame,' utilizing preparation, music, and psychotherapy to help patients process the subjective, dissociative experiences—ranging from disembodiment to profound insights—that occur during administration Montreal model is a comprehensive approach.
Despite its potential, ketamine presents a dual profile regarding safety and efficacy. While sub-anesthetic, single-dose paradigms often yield positive outcomes, chronic or high-dose exposure is associated with risks, including potential neurotoxicity, cognitive deficits, and bladder complications [fact:56|Ketamine exhibits a dual profile regarding neurogenesis and neural plasticity], Ketamine use is associated with safety. Furthermore, the transient nature of its antidepressant benefits remains a significant clinical challenge, necessitating ongoing research into maintenance strategies and alternative delivery methods, such as slow-release tablets, to improve affordability and reduce side effects Antidepressant benefits typically fade, A slow-release, tablet form of ketamine with minimal side-effects has the potential to make treatment more affordable.
Current research is also investigating the metabolite 2R,6R-hydroxynorketamine (2R,6R-HNK), which may mediate ketamine's therapeutic benefits without the dissociative side effects associated with the parent compound The metabolite 2R,6R-hydroxynorketamine (2R,6R-HNK) may mediate the positive effects. As the field evolves, the integration of pharmacological, psychological, and neurobiological perspectives continues to define ketamine's role as a versatile, albeit potent, intervention in modern mental health care.
Model Perspectives (7)
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Ketamine is a synthetic NMDA antagonist [fact:28|Ketamine and phencyclidine (PCP) are synthetic drugs] originally used as an anesthetic [fact:29|Ketamine and phencyclidine (PCP) were initially employed as anaesthetics] that has emerged as a significant, though complex, tool in psychiatric treatment. It is currently the only recognized medical NMDA antagonist [fact:55|Ketamine is currently the only NMDA antagonist recognized as a medical treatment]. A major breakthrough in depression research, ketamine is now a prescribed treatment for treatment-resistant depression in countries including the USA and Israel [fact:60|Ketamine is a prescriptible treatment for treatment-resistant depression].
Its therapeutic potential is often attributed to neuroplasticity, as it modulates glutamatergic receptors [fact:18|Ketamine acts on glutamatergic N-Methyl-D-Aspartate receptors] and increases brain-derived neurotrophic factor (BDNF) levels, which promotes synaptogenesis and neurogenesis [fact:33|Ketamine increases BDNF levels]. However, ketamine exhibits a dual profile: while sub-anesthetic, single-dose paradigms often yield positive neuroplastic and antidepressant effects [fact:35|Ketamine enhances synaptogenesis and neurite growth in young adult mice], high-dose or neonatal exposure can induce neurotoxic effects, including mitochondrial damage, reduced synapsin expression, and long-term cognitive deficits [fact:36|Zuo and colleagues observed that administering 30 mg/kg/day of ketamine...], [fact:56|Ketamine exhibits a dual profile regarding neurogenesis and neural plasticity].
Research is also focused on 2R,6R-hydroxynorketamine (2R,6R-HNK), a ketamine metabolite that may mediate therapeutic benefits like increased BDNF levels without the dissociative side effects—such as hallucinations or mania—associated with standard ketamine use [fact:47|2R,6R-hydroxynorketamine (2R,6R-HNK) does not act as an NMDAR antagonist], [fact:58|The metabolite 2R,6R-hydroxynorketamine (2R,6R-HNK) may mediate the positive effects]. Current clinical investigations are exploring ketamine’s role in treating 'diseases of despair' such as addiction and suicidality [fact:14|Modern medical researchers are investigating psychedelic compounds], [fact:15|Proponents of psychedelic-assisted therapy suggest that compounds like MDMA, LSD, psilocybin, and ketamine may help alter the perspectives of individuals suffering from 'diseases of despair']. Emerging delivery methods, such as slow-release tablets, are being researched to potentially improve affordability and minimize side effects [fact:1|A slow-release, tablet form of ketamine with minimal side-effects has the potential to make treatment more affordable].
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Ketamine is a pharmacological agent primarily investigated for its rapid-acting antidepressant effects Berman et al. (2000) reported antidepressant effects. Research into its clinical use has diverged into two main frameworks: the 'biomedical' approach and the 'psychedelic' approach Research has diverged into two bodies.
The biomedical approach emphasizes the drug's pharmacological and neural mechanisms, often viewing psychoactive side effects as unrelated to therapeutic efficacy Biomedical view of ketamine treatment. This model frequently employs dose-minimization strategies and standardized protocols, such as the 0.5 mg/kg intravenous infusion established in 2000 0.5 mg per kg dosing protocol. Conversely, the psychedelic approach, exemplified by the 'Montreal model,' integrates ketamine into a broader biopsychosocial intervention that includes psychotherapy and goal-oriented preparation, leveraging the patient's subjective experiences to support growth Montreal model integrates ketamine into therapy.
Mechanistically, ketamine is associated with neuroplasticity—a feature it shares with classical psychedelics Neuroplasticity as a convergent mechanism. Key biological mediators include Brain-Derived Neurotrophic Factor (BDNF) BDNF release is required for behavior, AMPA receptors, and mTOR signaling Ketamine enhances structural plasticity. While ketamine shows potential for treating treatment-resistant depression Montreal model is a comprehensive approach, anorexia Ketamine is being investigated as treatment, and substance use disorders Ketamine used for mental health disorders, it faces safety concerns, including abuse potential, cognitive risks, and bladder complications associated with chronic misuse Ketamine use is associated with safety. Furthermore, the transient nature of its antidepressant benefits remains a major clinical challenge Antidepressant benefits typically fade.
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Ketamine is a dissociative anesthetic with potential as a rapid-acting treatment for psychiatric conditions such as treatment-resistant depression and suicidality [21, 46]. While historically viewed through a biomedical lens, it is increasingly categorized as a 'psychoplastogen'—a substance that promotes neuroplasticity—and is applied in psychedelic-like treatment models [7, 3, 4]. Neuroimaging research suggests that ketamine shares core neural features with serotonergic psychedelics, including altered network connectivity and increased neural signal diversity [8]. Despite these similarities, ketamine's subjective effects are specifically noted for high levels of 'disembodiment' [12] and frequent experiences related to death and dying [48].
Clinical implementation of ketamine faces challenges regarding long-term maintenance, as its antidepressant effects often require repeated dosing [1]. To address these challenges, the 'Montreal model' has emerged as an integrative approach that combines biomedical administration with evidence-based psychotherapy [22, 27]. This model emphasizes the 'window of opportunity' for behavioral change following treatment [31] and utilizes the SMART framework for goal-setting [32, 33]. Unlike common practices where ketamine is administered in isolation [18], the Montreal model mandates concurrent psychotherapy [38] and encourages the discontinuation of benzodiazepines, which may dampen ketamine's efficacy [35, 36].
A critical component of the Montreal approach is the 'framing' of the ketamine experience. Rather than dismissing the drug's psychoactive effects as meaningless dissociation [53], clinicians frame them as potentially meaningful reflections of the patient's inner landscape [55]. This approach acknowledges that psychoactive effects—which can range from therapeutic insights to distress or panic [2, 39, 54]—are influenced by non-pharmacological factors such as the use of music [60], blindfolds [58], and the clinician's own attitude [52]. By providing a structured therapeutic frame, practitioners aim to transform potentially disorienting 'ketamine dreams' into opportunities for psychological exploration and catharsis [47, 56].
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Ketamine is an off-label treatment for depression that may offer symptomatic relief through enhanced neuroplasticity potential psychiatric benefits. While research into its use is expanding interest in re-emerging treatments, the "Montreal model" represents a specific biopsychosocial approach to its administration developed through clinical experience. This model emphasizes experiential learning to counter the passivity and rigidity often associated with Treatment-Resistant Depression (TRD) corrective force for TRD.
The Montreal model protocol involves six intravenous infusions of 0.5 mg/kg over 4 weeks standard treatment course, a schedule designed to spread the total duration of altered states of consciousness similarly to psilocybin treatment, but over a longer timeframe duration of altered states. The process includes preparatory sessions, music selection, and mindfulness exercises nine goals of preparation, aiming to help patients defuse difficult thoughts and engage with emotions gentle psychological approach.
Clinicians associated with this model caution that psychedelic-like administration carries risks, such as the potential for false memories or patient disappointment if expected mystical experiences do not occur clinical and ethical risks. Furthermore, developers of the Montreal model aim to minimize the frequency of ketamine treatments due to concerns regarding cost, burden, and potential long-term harms minimizing ongoing treatments, preferring a maintenance strategy that includes conventional psychotherapy and other medical interventions maintenance phase components.
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Ketamine is categorized as a non-classic hallucinogen, alongside substances like MDMA and ibogaine non-classic hallucinogens include. It is a psychoactive compound showing therapeutic promise for various psychiatric conditions, including major depressive disorder and mood disorders ketamine, 3,4-methylenedioxymethamphetamine (mdma), and ibogaine are. Scientific research into ketamine spans its neurobiological mechanisms—such as its role as an NMDA antagonist and its influence on neurotrophic factors like BDNF—to its clinical efficacy, safety, and potential for abuse the nmda antagonist ketamine and the 5-ht agonist psilocybin produce, ketamine, harmala alkaloids, and certain psychoactive tryptamines promote.
Clinical research has extensively evaluated ketamine for depression, including meta-analyses on its rapid antidepressant effects han et al. published a meta-analysis in 2016 and reviews of maintenance treatment smith-apeldoorn et al. published a 2022 systematic review. While it is often studied using single-dose paradigms 80% of ketamine studies utilize a single-dose paradigm, researchers are exploring its use in assisted psychotherapy, though models for this are less formalized than those for psilocybin psychedelic-assisted psychotherapy models for psilocybin are more formalized. Beyond mood disorders, ketamine has been investigated for its effects on substance use disorders, such as cocaine addiction a human-controlled trial at the new york state, as well as its neurocognitive impacts when chronically self-administered morgan et al. (2010) conducted a 1-year longitudinal.
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Ketamine is a pharmacologically active substance with diverse applications in clinical research, ranging from anesthesia and euthanasia [22] to the treatment of neuropsychiatric conditions. It is frequently studied for its rapid-acting antidepressant properties [34] and its potential to mitigate suicidal ideation [1, 6, 26, 41].
Clinical research has explored various delivery methods, including intravenous [1, 26], sublingual [27, 32], and oral administration [14]. In the context of depression and anxiety, ketamine is often compared to electroconvulsive therapy (ECT) [9, 33, 43], while its use as an adjunct in psychotherapy—often termed Ketamine-Assisted Psychotherapy (KAP)—has been documented across various practices [7, 18, 45]. Additionally, researchers have investigated ketamine's role in treating substance use disorders, such as cocaine dependence [19] and alcohol use disorder [5], and its potential utility in managing benzodiazepine withdrawal [20]. However, some studies suggest that concomitant use of benzodiazepines may undermine ketamine's antidepressant efficacy [30, 36].
Neuroscientifically, ketamine is characterized as a dissociative agent [16, 37] that exerts complex effects on the brain. Studies using magnetoencephalography (MEG) have reported that psychoactive doses increase spontaneous signal diversity [25, 29]. Research has also focused on its impact on glutamate and GABA neurotransmission [4, 24], its ability to inhibit stress-induced dendritic spine elimination via parvalbumin interneurons [17], and its influence on reward anticipation [35] and default mode network connectivity [13]. Furthermore, its psychotropic effects, including potential for induced unpleasant dreams [23] and its historical modeling of psychosis [12], continue to be a subject of investigation [11, 42].
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Ketamine is the subject of extensive neuroscience and psychiatry research, particularly regarding its psychotropic, antidepressant, and neurobiological effects. Muetzelfeldt et al. explored phenomenological aspects of ketamine use, including the 'K-hole' experience, published in Drug and Alcohol Dependence (2008). Polis et al. highlighted variability in rodent ketamine depression research in Behavioural Brain Research (2019). E.F. Domino discussed taming the ketamine tiger in Anesthesiology (2010), implying strategies for managing its potent effects. Lee et al. proposed ketamine's anti-suicide effects via procognition in the Journal of Clinical Psychopharmacology (2016). Cichon et al. found that ketamine triggers neocortical excitatory switch in Nature Neuroscience (2022). Earlier work by Hansen et al. examined ketamine's psychotropic effects in the Journal of Psychoactive Drugs (1988). Varley et al. compared ketamine and propofol on brain dynamics in PLOS Computational Biology (2020), while Spencer et al. studied ketamine's impact on inflammatory cytokines in rats, published in the Journal of Neuroinflammation (2022). These studies from Frontiers in Psychiatry references portray ketamine as a versatile compound with rapid psychiatric and neural impacts.
Facts (285)
Sources
The Montreal model: an integrative biomedical-psychedelic ... frontiersin.org 195 facts
procedureThe Montreal model clinical team proposes a trial of benzodiazepine and related sedative (BZDR) discontinuation for all patients, which typically entails a slow taper such that final doses occur within several days of the first ketamine treatment, due to evidence that benzodiazepines may dampen or shorten the antidepressant effects of ketamine.
measurementThe Montreal model's six intravenous ketamine treatments provide patients with a similar amount of time in an altered state of consciousness as two doses of psilocybin.
claimMost biomedical ketamine studies do not standardize or report non-pharmacological factors, such as the presence or absence of music during treatment sessions.
claimHuman studies have observed that ketamine transiently alters cerebral GABA and glutamate concentrations, increases neural activity in reward-processing areas, and potentially normalizes default mode network connectivity abnormalities associated with depression.
claimThe authors of the paper 'The Montreal model: an integrative biomedical-psychedelic ...' found that presenting ketamine experiences as reflective of the patient's inner landscape is consistent with the phenomenology of the drug and is beneficial.
claimA randomized controlled trial (RCT) investigating music with ketamine found that both music and non-music interventions were effective and tolerable in a patient population characterized by high rates of comorbidity, suicidality, and chronicity.
claimKetamine is considered a putative psychedelic with several advantages, including a long medical track record, efficacy in treating severe Treatment-Resistant Depression (TRD) and suicidality, treatment sessions that are approximately 75% shorter than other psychedelic therapies, minimal drug–drug interactions, and safety in patients with bipolar affective disorder 1.
claimThe use of blindfolds during ketamine treatment reduces external stimuli, which patients describe as increasing the intensity and degree of perceptual changes.
procedureIn the biomedical approach to ketamine treatment, psychoactive effects are often mitigated through strategies such as dose-minimization, reassurance, distraction, and the administration of sedatives.
referenceAbbar et al. conducted a double-blind, randomised, placebo-controlled trial published in the BMJ in 2022, which investigated the use of ketamine for the acute treatment of severe suicidal ideation.
referenceAnand et al. compared the efficacy of ketamine versus electroconvulsive therapy (ECT) for nonpsychotic treatment-resistant major depression in a study published in the New England Journal of Medicine in 2023.
claimFraming ketamine experiences as potentially meaningful can increase their attributed importance and clarity for patients.
claimThe authors of the Montreal model report that a brief course of ketamine evokes psychological dynamics that resemble an accelerated short-term psychotherapy more closely than a course of electroconvulsive therapy (ECT).
claimThe Montreal model utilizes concomitant psychotherapy, which allows patients to continue conventional psychotherapy sessions semi-independently of the ketamine treatment process at regular or as-needed frequencies.
claimKetamine provides therapeutic benefits against suicidality and cognitive symptoms of depression, which are partially independent of core mood improvements.
accountThe Montreal model was developed over 6 years and based on more than 500 ketamine treatments administered to inpatients and outpatients with severe treatment-resistant depression at two McGill University hospitals.
referenceHan et al. published a meta-analysis in 2016 in Neuropsychiatric Disease and Treatment on the efficacy of ketamine for the rapid treatment of major depressive disorder, based on randomized, double-blind, placebo-controlled studies.
claimThe clinical growth of at-home ketamine care models was partially accelerated by the relaxation of telehealth prescribing rules in the United States during the COVID-19 pandemic.
claimResearch into strategies to maintain or augment the antidepressant response to ketamine has yielded disappointing results for drugs including clonidine, D-cycloserine, lamotrigine, lithium, rapamycin, rapamycin, and riluzole.
claimThe term 'dreaming' was proposed by the creators of ketamine anesthesia before the label 'dissociative' was chosen.
claimKetamine experiences are often described as visions of current and past events juxtaposed with perceptual distortions, similar to how dreams contain bizarre transformations of memories and emotions.
referenceKenwood et al. (2019) explored the mechanisms of ketamine's antidepressant effects, specifically examining the role of vascular endothelial growth factor (VEGF) in mediating plasticity processes.
claimKetamine and psilocybin appear to act as 'psychoplastogens,' which are agents that rapidly boost neuroplasticity.
claimKetamine clinical trials frequently employ active comparators, such as midazolam, to reduce placebo effects and unblinding caused by the drug's psychoactive properties.
referenceS.T. Wilkinson, T.G. Rhee, J. Joormann, R. Webler, M. Ortiz Lopez, B. Kitay, et al. published 'Cognitive behavioral therapy to sustain the antidepressant effects of ketamine in treatment-resistant depression: a randomized clinical trial' in PPS in 2021.
referenceThe study 'Journey through the K-hole: phenomenological aspects of ketamine use' by Muetzelfeldt et al. was published in Drug and Alcohol Dependence in 2008.
claimEsketamine is utilized in clinical protocols that feature gradually less-frequent dosing, similar to the protocols used for intravenous ketamine.
claimMusic can significantly influence the content of ketamine experiences, with patients reporting that music generates vivid synesthetic visions, reduces anxiety, and supports the exploration of the experience.
referenceSilberbauer et al. conducted a human in vivo multivoxel magnetic resonance spectroscopy study on the effect of ketamine on limbic GABA and glutamate, published in Frontiers in Psychiatry.
referenceE. Dakwar, F. Levin, C.L. Hart, C.C. Basaraba, J. Choi, M. Pavlicova, et al. published 'A single ketamine infusion combined with motivational enhancement therapy for alcohol use disorder: a randomized midazolam-controlled pilot trial' in AJP in 2019.
claimThe Montreal model is an approach to integrating ketamine into a broader biopsychosocial intervention for treatment-resistant depression, designed to deliver feasible and robust clinical benefits.
referenceGrunebaum et al. (2017) conducted a midazolam-controlled randomized clinical trial to evaluate the use of ketamine for the rapid reduction of suicidal thoughts in major depression.
referenceJ. Dore, B. Turnipseed, S. Dwyer, A. Turnipseed, J. Andries, G. Ascani, et al. published 'Ketamine assisted psychotherapy (KAP): patient demographics, clinical data and outcomes in three large practices administering ketamine with psychotherapy' in the Journal of Psychoactive Drugs in 2019.
claimPsilocybin currently has stronger evidence than ketamine supporting the therapeutic potential of 'emotional breakthroughs' and mystical experiences in the treatment of depression.
claimThe ketamine treatment situation in the Montreal model is considered an ideal opportunity for behavioral modifications because patients' high expectations and desire to optimize treatment response translate into high levels of engagement in pursuing changes.
procedurePatients in the Montreal model are required to establish at least three mutually acceptable SMART goals to be initiated before beginning ketamine treatments and maintained throughout the process.
procedureThe Montreal model protocol for ketamine treatment involves six relatively brief ketamine infusions over a period of 4 weeks, which differs from the one or two longer psilocybin sessions typically employed in other psychedelic-assisted psychotherapy (PAP) studies.
procedureThe Montreal model requires patients to engage in at least one hour of weekly evidence-based psychotherapy, beginning at least two weeks before the initiation of ketamine treatments.
claimKetamine can provide 'windows of opportunity' for symptomatic relief from depression and psychologically beneficial treatment experiences, both of which facilitate longer-term efforts toward recovery.
referencePolis et al. examined the variability in rodent ketamine depression-related research, published in Behavioural Brain Research in 2019.
accountThe biomedical approach to ketamine treatment originated from a randomized controlled trial published in 2000, where seven depressed patients received an intravenous dose of 0.5 mg per kg of bodyweight infused over 40 minutes.
claimExperiences of death and dying are more common with ketamine than with any other psychotropic drug.
referenceMathew et al. (2019) published the ELEKT-D study protocol in Contemporary Clinical Trials, which compares electroconvulsive therapy (ECT) to ketamine for patients with treatment-resistant depression.
procedureThe Montreal model clinicians orient all phases of the ketamine treatment process toward cultivating curiosity for current-moment experiences, defusing challenging thoughts, and taking value-driven actions.
perspectiveThe authors of the Montreal model view ketamine experiences as valuable opportunities for experiential learning when paired with appropriate settings and mindsets, rather than viewing them as either essential drivers of psychological benefits or merely inconvenient treatment side-effects.
referenceBrendle et al. (2022) analyzed the cost-effectiveness of esketamine nasal spray compared to intravenous ketamine for patients with treatment-resistant depression in the United States, utilizing clinical trial efficacy and real-world effectiveness estimates.
claimThe biological mechanisms underlying ketamine's psychiatric benefits, including the role of NMDA receptors, remain a subject of ongoing research and debate.
claimKetamine and psilocybin can both produce rapid improvements in psychiatric conditions like depression that persist for days or weeks beyond the excretion of the drugs and their metabolites.
claimThe authors of the Montreal model suggest that establishing a 'psychotherapy-grade' therapeutic frame is vital for the safety and efficacy of ketamine treatment, especially when treating treatment-resistant depression (TRD) in patients with comorbidities like personality disorders.
claimKetamine treatment experiences can generate emotionally charged and potentially distressing psychological content, which can be harmful or treatment-interfering without adequate follow-up, but can lead to fruitful psychotherapeutic exploration with proper support.
referenceCeban et al. (2021) reviewed the prevention and management of common adverse effects associated with ketamine and esketamine treatment in patients with mood disorders.
referenceThe study 'The incidence of unpleasant dreams after sub-anaesthetic ketamine' by Blagrove et al. was published in Psychopharmacology in 2009.
measurementA randomized controlled trial (RCT) involving 32 patients compared the effects of music versus matched non-music support (such as relaxation or mindfulness exercises) during ketamine treatments.
referenceMcMillan and Muthukumaraswamy published an integrative review on the neurophysiology of ketamine in Reviews in the Neurosciences in 2020.
procedureKetamine treatment sessions in the Montreal model last approximately 2 hours and require at least one clinician to be present for safety monitoring and accompaniment in a dedicated room.
referenceEvans et al. (2018) measured default mode connectivity in patients with major depressive disorder up to 10 days following the administration of ketamine, as published in Biological Psychiatry.
referenceRosenblat et al. (2019) conducted a systematic review on the use of oral ketamine for the treatment of depression.
claimKetamine is an off-label treatment that may yield significant but transient psychiatric benefits, potentially by acting through enhanced neuroplasticity.
referenceThe article 'Taming the ketamine tiger' by E.F. Domino was published in Anesthesiology in 2010.
claimKetamine's acute psychoactive effects can cause distress, ranging from mild discomfort to acute panic attacks, which may lead to premature termination of treatment.
claimIntranasal esketamine, the s-enantiomer of ketamine, is dosed to minimize psychoactive effects and has received regulatory approval in multiple countries for unipolar treatment-resistant depression when used with conventional oral antidepressants.
claimThe Montreal model psychological approach to ketamine treatment is summarized as gentle encouragement to feel emotions, defuse thoughts, and change behaviors.
referenceNg et al. found that ketamine and the selective activation of parvalbumin interneurons inhibit stress-induced dendritic spine elimination, published in Translational Psychiatry in 2018.
referenceLiu et al. published a 2016 study in Brain Research Bulletin regarding ketamine abuse potential and use disorder.
claimSome at-home ketamine care models are described as partially 'psychedelic' because they frame the effects of ketamine in a specific way and incorporate elements such as telehealth psychological support.
referenceWinstock et al. (2012) investigated the prevalence and natural history of urinary symptoms among recreational ketamine users.
claimSerotonergic psychedelic and ketamine experiences exhibit significant phenomenological overlap.
referenceSmith-Apeldoorn et al. published a 2022 systematic review in The Lancet Psychiatry on the efficacy, safety, and tolerability of maintenance ketamine treatment for depression.
claimThe development of NMDA modulators intended to replicate ketamine's antidepressant effects without its psychoactive effects has largely failed, with drugs like memantine proving ineffective and many candidates being abandoned after costly clinical trials.
claimKetamine's subjective effects are distinguished from psilocybin primarily by higher scores on the 'disembodiment' subscale.
referenceKolp, Friedman, Krupitsky, Jansen, et al. published 'Ketamine psychedelic psychotherapy: focus on its pharmacology, phenomenology, and clinical applications' in the International Journal of Transpersonal Studies in 2014 (doi: 10.24972/ijts.2014.33.2.84), examining the clinical use of ketamine.
claimThe Montreal model developers aim to minimize the need for ongoing ketamine treatments because such treatments can be burdensome, costly, and potentially associated with long-term psychological and physiological harms.
referenceE. Dakwar, E.V. Nunes, C.L. Hart, R.W. Foltin, S.J. Mathew, K. Carpenter, et al. published 'A single ketamine infusion combined with mindfulness-based behavioral modification to treat cocaine dependence: a randomized clinical trial' in the American Journal of Psychiatry in 2019.
claimThe Montreal model clinicians suggest that the psychological processes underlying psychedelic ketamine experiences are not specific to ketamine or Treatment-Resistant Depression, but may arise in any therapeutic situation where a patient receives a powerful psychoactive drug with psychological accompaniment.
claimThe Montreal model recommends screening for obstructive sleep apnea during the medical history assessment for ketamine treatment, as it is a condition commonly associated with depression.
measurementIn a cohort study of treatment-resistant depression (TRD) patients receiving ketamine under the Montreal model, all patients were willing to attempt benzodiazepine receptor (BZDR) discontinuation, nearly all achieved total abstinence during treatment, and the majority remained BZDR-free after an average follow-up of one year.
claimPurcell et al. published a paper in Cureus in 2021 identifying ketamine as a potential adjunct for severe benzodiazepine withdrawal.
claimKetamine use is associated with safety considerations including stimulatory hemodynamic effects, abuse potential, and long-term risks such as cognitive and bladder harms.
claimThe differences in care models for psilocybin and ketamine are likely driven by sociohistorical factors, such as ketamine's established use as a medical anesthetic versus psilocybin's disappearance and recent re-emergence, rather than pharmacological or neural differences.
procedureThe Montreal model requires two to three preparatory sessions, ranging from 30 to 60 minutes in length, for patients deemed good candidates for ketamine treatment prior to beginning the treatment process.
claimResearch on ketamine in psychiatry has diverged into two bodies of thought: the 'biomedical' approach and the 'psychedelic' approach.
claimPsilocybin-assisted psychotherapy (PAP) protocols serve as the primary basis for most contemporary psychedelic ketamine models, despite a lack of clinical trials specifically employing psychedelic models for ketamine.
claimRecent neuroimaging research indicates that despite pharmacological differences, serotonergic psychedelics and ketamine share neural features, specifically heightened neural signal diversity, reduced within-network connectivity, and enhanced between-network connectivity.
claimThe Montreal model of ketamine administration may be valuable for treating patients grappling with depression in the final stages of life.
claimThe 0.5 mg per kg intravenous dosing protocol established in the year 2000 remains the most commonly used ketamine administration protocol globally, though modifications exist for specific patient populations or side-effect mitigation.
referenceJohnston et al. provided an update on the mechanisms and biosignatures underlying rapid-acting antidepressant treatment involving ketamine and serotonergic psychedelics, published in Neuropharmacology in 2023.
procedureThe Montreal model incorporates the 'Specific Measurable Achievable Relevant Timely' (SMART) framework for behavioral goal-setting during the evaluation and preparation phases of ketamine treatment.
claimThe Montreal model's flexible approach to psychotherapy integration provides feasibility benefits by removing the requirement for all treating clinicians to be experts in both conventional psychotherapy and ketamine or psychedelic-assisted approaches.
claimThe Montreal model for ketamine treatment seeks to enhance patient engagement in evidence-based psychotherapy by leveraging ketamine's pro-cognitive and anti-suicide effects, as well as the psychological experiences of dosing sessions.
procedureThe Montreal model ketamine treatment process includes the following steps: (1) beginning each treatment with brief exercises like body scans or mindful focusing of attention on the breath, (2) encouraging patients to avoid suppressing emotions or labeling sensations with judgmental terms, (3) encouraging patients to fully experience sensations without becoming entangled in associated cognitions, and (4) maintaining this orientation throughout the ketamine experience and between sessions.
referenceAndrade (2017) reviewed clinical parameters for ketamine use in depression, specifically addressing dosage, rate of administration, route, duration, and frequency.
accountTwo recent ketamine-psychotherapy trials administered ketamine disjointly from mindfulness-based psychotherapy, meaning patients did not receive psychological support or psychedelic-like contexts during the ketamine infusions.
claimPatients are prone to dismissing ketamine experiences as meaningless if the experiences are introduced to them as pathological or meaningless.
claimThe Montreal team incorporated inspiration from emerging psychedelic research into their ketamine dosing sessions while simultaneously building upon the evidence base for conventional psychiatric and psychotherapeutic interventions.
procedureThe Montreal model for ketamine treatment includes four major components: a targeted psychiatric assessment, goal-oriented preparation, weekly concomitant psychotherapy, and a course of intravenous (IV) racemic ketamine infusions consisting of six subanesthetic doses administered over 4 weeks in psychedelic-like treatment contexts.
referenceBahji et al. (2021) conducted a systematic review of ketamine use for bipolar depression.
referenceThe study 'Brief report: the effect of suggestion on unpleasant dreams induced by ketamine administration' by Cheong et al. was published in Anesth Analg in 2011.
referenceVankawala et al. published a 2021 meta-analysis in Frontiers in Psychiatry regarding hemodynamic responses to sub-anesthetic doses of ketamine in patients with psychiatric disorders.
procedureThe authors of the Montreal model mitigate the risks of patient disappointment and potential suicidality by systematically incorporating explicit discussions about treatment expectations during initial evaluations, emphasizing behavioral changes and establishing backup plans if ketamine treatment is unsuccessful.
referenceAbdallah et al. (2018) investigated the effects of ketamine on prefrontal glutamate neurotransmission in both healthy and depressed subjects, as published in Neuropsychopharmacology.
claimAdministering ketamine in psychedelic-like contexts carries clinical and ethical risks, including the potential for false memories of past traumas and patient disappointment when expected mystical experiences do not occur.
referenceWilkinson et al. conducted a systematic review and individual participant data meta-analysis on the effect of a single dose of intravenous ketamine on suicidal ideation, published in the American Journal of Psychiatry in 2018.
claimThe Montreal model of ketamine treatment spreads the total duration of altered states of consciousness over 4 weeks, whereas psilocybin treatment typically occurs over one or two sessions.
claimKetamine can cause distressing psychoactive effects in both recreational and medical contexts, leading to debate regarding the therapeutic importance of these altered states of consciousness.
claimWhile some experts define the term 'psychedelic' specifically as agonists of serotonin 2A receptors (such as psilocybin), psychedelic treatment models have been applied to diverse psychoactive drugs including MDMA, ibogaine, cannabis, and ketamine.
referenceHassan et al. (2022) performed a retrospective study on the safety, effectiveness, and tolerability of sublingual ketamine for the treatment of depression and anxiety in an at-home, off-label setting.
claimThe Montreal model uses the Dutch Method to stage treatment resistance in patients undergoing psychiatric assessment for ketamine treatment.
procedureThe Montreal model for ketamine treatment discharges patients once they are psychologically and physiologically ready, with vital signs within normal limits, and provides them with safety reminders and instructions to contact clinicians in case of adverse reactions or distress.
measurementThe Montreal model's six ketamine treatments yield approximately the same amount of time in an altered state of consciousness as 12 psilocybin treatments, but spread out over multiple sessions.
claimThe Montreal model was evaluated in a pragmatic randomized controlled trial (RCT) examining how music influences the physiological and psychological effects of ketamine.
referenceLee et al. proposed a new perspective on the anti-suicide effects of ketamine treatment, suggesting it acts through a procognitive effect, as published in the Journal of Clinical Psychopharmacology in 2016.
referenceSchartner, Carhart-Harris, Barrett, Seth, and Muthukumaraswamy published 'Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin' in Scientific Reports in 2017 (doi: 10.1038/srep46421), reporting on MEG signal changes.
accountThe Montreal model of psychedelic therapy was evaluated in a randomized controlled trial (RCT) examining the effects of music on ketamine infusions in patients with treatment-resistant depression (TRD).
referenceA clinical trial titled 'Music as an intervention to improve hemodynamic tolerability of ketamine in depression' is registered on ClinicalTrials.gov (NCT04701866) as of 2023.
claimThe Montreal model clinicians utilize the concept of a 'window of opportunity' following ketamine treatment, which refers to a period of symptomatic improvement and potentially enhanced neuroplasticity.
procedureThe Montreal model maintenance phase for treatment-resistant depression (TRD) consists of three forms: medication/neurostimulation, concomitant psychotherapy, and maintenance ketamine treatments.
claimThe RAPID intravenous ketamine study, published by Feeney et al. in the Journal of Clinical Psychiatry in 2022, investigated the effect of concomitant benzodiazepines on the antidepressant effects of ketamine.
referenceFeifel, Dadiomov, and Lee published a 2020 study in Pharmaceuticals regarding the safety of repeated parenteral ketamine administration for depression.
claimThe 'rolling' therapeutic rhythm associated with the Montreal model of ketamine administration is potentially well-suited for managing patient expectations, navigating psychological challenges, and supporting behavioral changes in highly refractory cases.
procedureTypical biomedical models of care for parenteral ketamine involve administering treatments twice or thrice weekly for several weeks to induce remission, followed by maintenance treatments at a decreasing frequency.
claimPsychedelic-assisted psychotherapy models for psilocybin are more formalized and better supported by clinical research than equivalent models for ketamine.
referenceMcMullen et al. published a 2021 study in Advances in Therapy regarding strategies to prolong the efficacy of ketamine in adults with treatment-resistant depression.
referenceConley et al. published a meta-analysis in Psychopharmacology in 2021 evaluating the efficacy of ketamine for major depressive episodes at 2, 4, and 6 weeks post-treatment.
referenceCichon et al. reported that ketamine triggers a switch in excitatory neuronal activity across the neocortex, published in Nature Neuroscience in 2022.
claimThe Montreal model for ketamine treatment incorporates nonpharmacological psychedelic adjuncts, such as music and psychological support, to ensure treatment experiences serve as opportunities for psychotherapeutic growth.
referenceMathai et al. (2020) performed a systematic review on the relationship between subjective effects induced by a single dose of ketamine and the subsequent treatment response in patients with major depressive disorder.
accountThe authors of the paper 'The Montreal model: an integrative biomedical-psychedelic ...' have administered ketamine in settings ranging from dedicated outpatient spaces to barren inpatient facilities.
referenceHull et al. (2022) conducted a large, prospective, open-label effectiveness trial which found that at-home, sublingual ketamine telehealth is a safe and effective treatment for moderate to severe anxiety and depression.
measurementSubanesthetic dosages of ketamine (e.g., 0.5 mg/kg) can produce powerful psychedelic experiences, including high scores on the Mystical Experience Questionnaire, when combined with contextual factors like blindfolds.
accountA clinical trial evaluating whether Cognitive Behavioral Therapy (CBT) could prolong the benefits of ketamine in patients who responded to six infusions over three weeks yielded mixed results.
claimThe antidepressant benefits of ketamine for treatment-resistant depression typically fade within days or weeks of administration.
claimClinical trials and observational studies have confirmed that intravenous ketamine has rapid antidepressant effects in unipolar depression and, with less evidence, in bipolar depression.
procedureThe Canadian Biomarker Integration Network in Depression (CAN-BIND) study protocol utilizes an ECT-like approach to intravenous ketamine, consisting of an acute treatment period of thrice-weekly doses followed by maintenance doses that decrease in frequency over six months, moving from weekly to monthly intervals.
claimThe personal significance of ketamine experiences is shaped by the framing provided to the patient, similar to how the interpretation of dreams varies across cultures and psychotherapy schools.
claimKetamine is considered by the authors to be the most forgiving putative psychedelic due to its short duration of action and lower levels of distress compared to classical psychedelics like psilocybin and LSD when administered in medical environments.
accountThe authors of the paper 'The Montreal model: an integrative biomedical-psychedelic ...' shifted their clinical approach to presenting ketamine's effects as reflections of the patient's mind and context, rather than as meaningless dissociation.
perspectiveThe Montreal model for ketamine treatment aims to utilize the rapid, transient antidepressant effects of ketamine to facilitate evidence-based psychiatric care, including lifestyle modifications and medication optimization.
claimScientific publications describing the use of ketamine in psychedelic-like models appeared within a decade of ketamine's discovery in 1962.
claimThe Montreal model administers ketamine treatments using 'psychedelic paradigm' hallmarks, which include the use of blindfolds, 'rolling' integrative and preparatory psychological support, and music or mindfulness exercises.
measurementKetamine treatment sessions for psychedelic-assisted approaches range from one to dozens of sessions, with dosages ranging from 0.1 mg up to and beyond 4 mg/kg administered parenterally, and routes of administration including intravenous, sublingual, intramuscular, and oral.
measurementThe Montreal model offers one-off ketamine maintenance sessions for responders at a frequency of approximately every 4–6 months.
referenceEkstrand et al. (2021) conducted a randomized, open-label, non-inferiority trial (KetECT) comparing racemic ketamine to electroconvulsive therapy for the treatment of unipolar depression.
claimThe Montreal model for ketamine treatment does not mandate a specific type of psychotherapy, but instead requires the use of any evidence-based approach, such as Cognitive Behavioral Therapy (CBT) or Acceptance and Commitment Therapy (ACT), that the patient is willing to pursue.
referenceDuman published an article titled 'The dazzling promise of ketamine' in the journal Cerebrum in 2018.
referenceWilkinson et al. (2019) analyzed the impact of using midazolam versus saline as a control on effect size estimates in controlled trials of ketamine as a rapid-acting antidepressant.
referenceGarel et al. explored the potential role of ketamine for depression in requests for medical aid in dying, published in International Clinical Psychopharmacology in 2023.
claimThe Montreal model aims to facilitate experiential learning with ketamine treatments to cultivate engaged, collaborative, and flexible life orientations as a corrective force to the passivity, rigidity, and nihilism commonly found in Treatment-Resistant Depression (TRD).
claimKetamine and psilocybin have both been used as experimental models of psychosis.
claimThe Montreal model of ketamine treatment incorporates patient choice regarding music selection, behavioral goals, and the nature of psychological support (such as quiet accompaniment, breathing exercises, or guided body scans) during the six treatment sessions.
referenceFrancois et al. (2016) conducted a cross-species translational neuroimaging study published in Neuropsychopharmacology, which demonstrated that ketamine suppresses the ventral striatal response to reward anticipation.
claimClinicians can influence a patient's perception of a ketamine experience through explicit statements or implicit communications, such as demonstrating curiosity.
referenceWilkinson et al. published a 2018 study in the Journal of Clinical Psychiatry on acute and longer-term outcomes of using ketamine as a clinical treatment at the Yale psychiatric hospital.
claimKetamine experiences involving autobiographical memories, symbolism, or media exposure can provide catharsis or insight, provided there is supportive context and psychological support.
claimAndrashko et al. reported in European Neuropsychopharmacology in 2019 that concurrent benzodiazepines undermine the antidepressant effect of ketamine.
referenceSanacora et al. (2017) published a consensus statement regarding the use of ketamine in the treatment of mood disorders.
referenceThe article 'A unified model of ketamine’s dissociative and psychedelic properties' by Marguilho et al. was published in the Journal of Psychopharmacology in 2023.
referenceThe article 'The psychotropic effect of ketamine' by Hansen et al. was published in the Journal of Psychoactive Drugs in 1988.
referenceVarley et al. investigated the differential effects of propofol and ketamine on critical brain dynamics, published in PLOS Computational Biology in 2020.
accountPatients in the early Montreal model ketamine trials experienced "termination reactions," characterized by reemergent symptoms near the end of the treatment course, because a positive clinical response resulted in fewer treatment sessions and less contact with the clinical team, which patients perceived as beneficial.
claimA notable strength of the ketamine clinical literature is the frequent inclusion of real-world treatment-resistant depression (TRD) patients who are often excluded from other clinical trials due to severity and comorbidity.
claimKetamine and serotonergic psychedelics are re-emerging as potential treatments for depression, generating considerable interest.
procedureThe Montreal model of ketamine treatment for depression is conducted similarly to acute treatments, with an emphasis on revisiting behavioral goals and experiential learning.
referenceThe Cochrane Common Mental Disorders Group (2021) published a systematic review in the Cochrane Database of Systematic Reviews regarding the use of ketamine and other glutamate receptor modulators for treating adults with unipolar major depressive disorder.
referenceThe Montreal model is a comprehensive biopsychosocial approach to using ketamine for severe treatment-resistant depression that was refined over six years in public healthcare settings.
claimPatients referred to the Montreal model service often arrive with unrealistically high expectations for ketamine, anticipating miraculous benefits, a phenomenon the authors describe as paralleling a broader psychedelic 'hype bubble'.
claimFraming ketamine experiences as meaningful can increase their vividness and perceived insight, but can also increase the distress associated with negative experiences like near-death experiences.
claimIn the Montreal model, the vast majority of patients receive conventional medications, such as antidepressants and mood stabilizers, before, during, and after the ketamine treatment process, and some patients also opt for neurostimulation treatments like transcranial magnetic stimulation.
claimThe Montreal model clinical team observed that ketamine treatment differs from electroconvulsive therapy (ECT) because termination of treatment is a critical consideration in psychotherapy, whereas it is generally only a subject of interest in psychiatry.
claimKetamine's rapid benefits against suicidality and the cognitive impairments of depression theoretically reduce obstacles to productive psychotherapy.
procedureThe Montreal model for ketamine treatment preparation involves nine specific goals: (1) establishing a treatment frame, (2) cultivating a therapeutic alliance, (3) psychoeducation and management of expectations, (4) determining behavioral treatment goals, (5) optimizing medications, (6) framing the ketamine experience, (7) trial mindfulness exercise, (8) music discussion, and (9) arranging for concomitant psychotherapy.
claimAnesthesia literature uses both the terms 'dissociative anesthetic' and 'ketamine dreams' to describe the effects of ketamine.
claimN,N-Dimethyltryptamine (DMT) and nitrous oxide are short-acting psychedelic-like drugs that may be employed in therapeutic models similar to the Montreal model of ketamine administration.
claimPreclinical and clinical evidence suggests that ketamine can mitigate psychological benzodiazepine receptor (BZDR) withdrawal symptoms.
claimCellular and animal studies indicate that ketamine can promote neuroplasticity, such as dendritic spinogenesis, reduce inflammation, and alter neural dynamics.
claimThe Montreal model for ketamine treatment excludes patients with active substance use due to potential iatrogenic harms, but does not exclude patients with personality disorders or acute suicidality, provided safety concerns are managed.
claimSome clinical studies have evaluated at-home sublingual or oral ketamine doses prescribed up to three times per day, which represents an approach more resemblant of oral antidepressants than the ECT-like parenteral models.
measurementWhen measured on the Altered States of Consciousness Rating Scale, ketamine and psilocybin produce similar results, including elevations in subscales for insightfulness, audio-visual synesthesia, and changed meaning of precepts.
referenceZhou et al. found that cognitive function mediates the anti-suicide effect of repeated intravenous ketamine in adult patients with suicidal ideation, as published in Frontiers in Psychiatry in 2022.
claimKetamine demonstrates safety and benefits in suboptimal real-world contexts, even without psychological support, and is effective for highly severe patients, including those with active suicidality and bipolar disorder.
accountAt the outset of the clinic, the Montreal model clinical team proposed a protocol of three ketamine infusions for appropriate patients, with subsequent treatments decided based on clinical response, similar to the protocol used for electroconvulsive therapy (ECT).
measurementThe standard ketamine treatment course in the Montreal model consists of six infusions administered over 4 weeks, with a dosage of 0.5 mg/kg infused over 40 minutes, twice per week for the first 2 weeks and once weekly for the final 2 weeks.
referenceL. Li and P.E. Vlisides published 'Ketamine: 50 years of modulating the mind' in Frontiers in Human Neuroscience in 2016.
claimThe Montreal model's approach of conducting psychotherapy concomitantly with, but somewhat independently of, ketamine treatments is atypical for psychedelic-assisted therapy but common in standard psychiatric care models.
claimThe Montreal model of ketamine treatment frames the intervention as one that can yield significant benefits, but notes that these benefits are likely to be transient.
referenceMorgan et al. (2010) conducted a 1-year longitudinal study on the consequences of chronic ketamine self-administration, finding impacts on neurocognitive function and psychological wellbeing.
referencePhillips et al. (2020) published a study protocol in BMC Psychiatry for a randomized, crossover comparison of ketamine and electroconvulsive therapy for the treatment of major depressive episodes, conducted by the Canadian Biomarker Integration Network in Depression (CAN-BIND).
claimNo published clinical trial has explored the use of ketamine with concomitant psychotherapy to treat depression.
claimClinical use of ketamine or esketamine has not been associated with iatrogenic dependence, cognitive decline beyond transient memory disruption, or toxic bladder effects.
referenceThe Montreal model of ketamine for treatment-refractory depression is a biopsychosocial approach developed gradually over years of real-world clinical experiences and research endeavors.
perspectiveThe biomedical view of ketamine treatment considers dose-related psychoactive effects to be unrelated to therapeutic efficacy and emphasizes pharmacological and neural effects as the primary mechanisms of action.
claimThe most common strategy for prolonging the benefits of ketamine in treatment-resistant depression is the readministration of ketamine, despite a lack of evidence regarding the long-term safety, efficacy, and feasibility of this practice.
referenceSpencer et al. studied the effects of an intravenous ketamine infusion on inflammatory cytokine levels in male and female Sprague–Dawley rats, published in the Journal of Neuroinflammation in 2022.
claimKetamine abuse has been linked to serious urinary tract complications and long-lasting adverse impacts on the nervous system and cognitive functioning, including the loss of gray matter volume.
claimAntidepressant response to ketamine is primarily achieved and maintained through repeated dosing, which may be required on an indefinite basis, leading to potential issues with long-term expense, inconvenience, imperfect adherence, and adverse side effects.
referenceWei et al. (2020) provided a historical review of the antidepressant effects of ketamine and its enantiomers.
Effects of psychedelics on neurogenesis and broader neuroplasticity link.springer.com Dec 19, 2024 61 facts
perspectiveResearchers suggest that ketamine-induced brain plasticity and subjective psychedelic experiences may offer benefits for addiction treatment and should be monitored in assisted psychotherapy.
referenceBrowne and Lucki (2013) reviewed the mechanisms underlying the fast-acting antidepressant effects of ketamine.
referenceBerman et al. (2000) reported that ketamine exhibits antidepressant effects in depressed patients.
claimThe discovery of ketamine's rapid antidepressant effect was considered by some researchers the greatest breakthrough in depression research over the past half-century.
claimKetamine has therapeutic potential for the treatment of alcohol use disorder, as discussed in a 2021 review published in Neuroscience & Biobehavioral Reviews.
claimKetamine exhibits a dual profile regarding neurogenesis and neural plasticity: it promotes synaptogenesis, neurite growth, and new neuron formation in single-dose paradigms, but high doses or neonatal exposure are linked to neurogenesis impairment and long-term cognitive deficits.
accountA human-controlled trial at the New York State Psychiatric Institute found that ketamine administered to cocaine-addicted patients who were not seeking treatment or abstinence reduced their cocaine self-consumption and resulted in high scores on the Hood Mysticism Scale (HMS) compared to the Clinician-Administered Dissociative States Scale (CADSS) and the Near-Death Experience Scale (NDES).
claimNOX2 knockout mice exhibit a reduced number of radial glial-like (RGL) cells compared to wild-type mice in adulthood, suggesting that NOX2 overexpression may play a role in ketamine's bimodal, dose-dependent effect on RGL proliferation.
claimHuang et al. (2016) reported that ketamine affects the neurogenesis of the hippocampal dentate gyrus in 7-day-old rats.
claimKetamine metabolites exhibit antidepressant actions that are independent of NMDAR inhibition, as reported in a 2016 study in Nature.
claimGoulart et al. (2010) observed that ketamine administration led to a dose-dependent attenuation of the BDNF increase normally stimulated by the novel object recognition (NOR) task when assessed approximately five hours post-training and injection.
claimIn the study by Huang et al. (2016), while cell levels in neonatal rats returned to control numbers 21 days after high-dose ketamine exposure, cognitive deficits persisted until at least postnatal day 60 as assessed by the Morris Water Maze (MWM).
claimKetamine is recognized for positively influencing adult neurogenesis subprocesses, including proliferation, differentiation, and survival of new neurons, through the upregulation of BDNF.
claimKetamine treatment in responders is associated with an increase in Slow Wave Sleep (SWS) duration, a finding observed by Duncan et al. (2013) and reproduced by Haile et al. (2014).
claimGSK-3 inhibition potentiates the synaptogenic and antidepressant-like effects of subthreshold doses of ketamine.
claimKetamine, harmala alkaloids, and certain psychoactive tryptamines promote the proliferation, differentiation, and survival of neurons in the adult brain, often through the upregulation of neurotrophic factors such as BDNF.
claim2R,6R-hydroxynorketamine (2R,6R-HNK) does not act as an NMDAR antagonist and lacks the dissociative side effects typically associated with ketamine.
claim2R,6R-hydroxynorketamine (2R,6R-HNK), a metabolite of ketamine, may play a significant role in mediating antidepressant and neuroplastic effects.
referenceA subset of psychoactive effects may be critical to the behavioral impact of ketamine on cocaine use disorder, according to a 2018 randomized, controlled laboratory study by Dakwar et al. published in Neuropharmacology.
claimHuang et al. (2016) found that high doses of ketamine administered to neonatal rats transiently reduced neuronal proliferation and altered differentiation in the dentate gyrus (DG).
referenceFan N, Luo Y, Xu K, et al. reported in a 2015 study in Schizophrenia Research that chronic ketamine abuse is associated with serum levels of TNF-α, IL-6, and IL-18 and schizophrenia-like symptoms.
claimKetamine induces a dissociative state, which may lead to side effects ranging from hallucinations to mania.
referenceCavalleri L, Merlo Pich E, Millan MJ, Chiamulera C, Kunath T, Spano PF, and Collo G published 'Ketamine enhances structural plasticity in mouse mesencephalic and human iPSC-derived dopaminergic neurons via AMPAR-driven BDNF and mTOR signaling' in 'Molecular Psychiatry' in 2018.
claimKetamine and its metabolite (2R,6R)-hydroxynorketamine induce lasting alterations in glutamatergic synaptic plasticity within the mesolimbic circuit, according to a 2018 study in Molecular Psychiatry.
claimKetamine is currently the only NMDA antagonist recognized as a medical treatment.
referenceSial OK, Parise EM, Parise LF, Gnecco T, and Bolaños-Guzmán CA published a review in 2020 titled 'Ketamine: the final frontier or another depressing end?' discussing the therapeutic potential and limitations of ketamine.
measurementA single 0.5 mg/kg ketamine infusion led to an increase in serum brain-derived neurotrophic factor (BDNF) levels when assessed 230 minutes after the infusion.
claimZuo and colleagues observed that administering 30 mg/kg/day of ketamine to male rats between postnatal days 35–42 resulted in a reduction of synapsin expression in the hippocampus.
claimMuscat S-A, Hartelius G, Crouch CR, and Morin KW proposed an integrative approach to ketamine therapy in 2021, suggesting it may enhance multiple dimensions of efficacy for treating treatment-resistant depression.
claimThe metabolite 2R,6R-hydroxynorketamine (2R,6R-HNK) may mediate the positive effects of ketamine, such as enhanced synaptic plasticity and increased BDNF levels, without causing the dissociative side effects associated with ketamine.
claimKetamine treatment in adolescent mice induces hyperlocomotion, anxiety, ataxia, stereotyped behaviour, mitochondrial damage, and morphological abnormalities in hippocampal and cortical cells, alongside increased dopamine and glutamate levels in the cortex and hippocampus.
claimHaile et al. (2014) investigated the relationship between plasma brain-derived neurotrophic factor (BDNF) levels and the response to ketamine in patients with treatment-resistant depression.
measurementHuang et al. (2016) found that four sub-anesthetic intraperitoneal injections of 10 mg/kg ketamine administered over 4 hours to postnatal day 7 (P7) rats led to a reduction in neuronal and glial proliferation up to 14 days post-injection, but levels returned to control levels by 21 days post-injection.
claimKetamine addiction can lead to low-grade inflammation.
referenceAleksandrova and Phillips (2021) identified neuroplasticity as a convergent mechanism shared by ketamine and classical psychedelics.
measurementIn treatment-resistant depression (TRD) patients, non-responsiveness to ketamine treatment is correlated with decreased brain-derived neurotrophic factor (BDNF) levels 7 and 14 days after a single 0.5 mg/kg ketamine infusion.
claimThe metabolite 2R,6R-HNK may contribute to the positive effects of ketamine on neurogenesis through the upregulation of brain-derived neurotrophic factor (BDNF).
referenceHashimoto (2019) provided a historical overview and future perspective on ketamine and its metabolites as rapid-acting antidepressants.
claimSome studies indicate that ketamine can cause neurotoxic effects, such as reductions in synapsin expression and mitochondrial damage, under certain conditions.
claimKetamine and phencyclidine (PCP) were initially employed as anaesthetics in the late 20th century.
measurementKetamine enhances synaptogenesis and neurite growth in young adult mice when administered at subanaesthetic doses ranging from 0.25 to 10 mg/kg/day.
claimAlcohol aggravates ketamine-induced behavioral, morphological, and neurochemical alterations in adolescent rats through the involvement of CREB-related pathways, according to a 2018 study in Behavioural Brain Research.
measurementAmong in vivo ketamine studies, the most frequently used behavioural assessment is the forced swim test (40%), followed by the open field test (20%).
referenceLepack AE et al. established that BDNF (Brain-Derived Neurotrophic Factor) release is required for the behavioral actions of ketamine.
claimSchiavone et al. (2020) found that intermittent administration of 30 mg/kg ketamine to neonatal rats (P7, P9, P11) caused a two-fold increase in NOX2 that persisted into adulthood, leading to neurochemical imbalances and oxidative stress.
claimKetamine treatment in patients with major depressive disorder induces plasticity, as indicated by concomitant changes in Brain-Derived Neurotrophic Factor (BDNF) levels and sleep slow waves.
claimA rat model of schizophrenia using ketamine showed increased neurogenesis.
claimKetamine is being investigated as a treatment for anorexia nervosa.
claimSerotonin can promote neurogenesis independently of BDNF, implying that ketamine's influence on neurogenesis may involve the modulation of serotonergic pathways.
claimGoulart et al. (2010) found that ketamine impairs recognition memory consolidation and prevents learning-induced increases in hippocampal brain-derived neurotrophic factor (BDNF) levels in rats.
claimKetamine and phencyclidine (PCP) are synthetic drugs originally discovered at the Parke-Davis Research Center and are among the most studied NMDA antagonists.
claimKetamine is used for the treatment of mental health and substance use disorders, as reviewed in a 2022 systematic review by Walsh et al. published in BJPsych Open.
referenceFive studies explored the effects of ketamine in humans, including one cross-sectional study with ketamine-addicted patients (Fan et al. 2015) and four controlled trials (Dakwar et al. 2018; Duncan et al. 2013; Haile et al. 2014; Rybakowski et al. 2013).
claimKetamine generally enhances neurogenesis and synaptic plasticity in adult subjects, which contrasts with the effects of high-dose ketamine in neonatal animals.
claimKetamine increases BDNF levels, which promotes synaptogenesis, neurite growth, and neurogenesis.
measurement80% of ketamine studies utilize a single-dose paradigm.
claimKetamine is a prescriptible treatment for treatment-resistant depression (TRD) in the USA and Israel, with many other countries implementing this treatment, according to Mathai et al. (2020).
referenceAkinfiresoye and Tizabi (2013) investigated the antidepressant effects of combining AMPA and ketamine, specifically examining the role of hippocampal BDNF, synapsin, and mTOR.
claimEarly high-dose ketamine exposure can disrupt neurogenesis during critical developmental periods, leading to lasting cognitive impairments, potentially mediated by alterations in BDNF signaling.
referenceThere is a relationship between subjective effects induced by a single dose of ketamine and the treatment response in patients with major depressive disorder.
measurementThe United States produced the highest number of studies on psychedelics (n = 18) in the analyzed sample, with a primary focus on ketamine (n = 7) and cannabinoids (n = 4).
Published Studies — Johns Hopkins Center for Psychedelic and ... hopkinspsychedelic.org 6 facts
referenceA 2023 systematic review by Medeiros et al. published in 'The Lancet Psychiatry' examined brain-based correlates of antidepressant response to ketamine.
referenceMathai, D. S., Mora, V., and Garcia-Romeu, A. published a study in Frontiers in Psychology in 2022 regarding the potential synergies of combining ketamine and psychotherapy.
referenceMathai, D. S., Lee, S. M., Mora, V., O’Donnell, K. C., Garcia-Romeu, A., and Storch, E. A. published a study in the Journal of Affective Disorders in 2022 regarding consent practices for the outpatient psychiatric use of ketamine.
referenceA 2025 study published in Acta Médica Portuguesa by Mota et al. examined the attitudes and perceptions of Portuguese psychiatrists and psychologists regarding the clinical use of ketamine.
referenceMathai, D. S., McCathern, A. G., Guzick, A. G., Schneider, S. C., Weinzimmer, S. A., Cepeda, S. L., Garcia-Romeu, A., and Storch, E. A. published 'Parental Attitudes Toward Use of Ketamine in Adolescent Mood Disorders and Suicidality' in the Journal of Child and Adolescent Psychopharmacology in 2021.
referenceA 2025 study published in bioRxiv by Agnorelli et al. utilized a multimodal approach to detect neuroplastic effects induced by ketamine in healthy human subjects.
Ancient Roots of Today's Emerging Renaissance in ... link.springer.com 6 facts
claimKetamine may be effective when administered in standard clinical infusions, according to Corriger and Pickering (2019).
claimIn the last decade, governing bodies have approved clinical trials for MDMA, ketamine, LSD, psilocybin, and dimethyltryptamine.
claimKetamine acts on glutamatergic N-Methyl-D-Aspartate receptors, and like classic psychedelics, it induces neuroplastic changes that may lead to therapeutic benefits.
referenceSatoshi Deyama and Ronald S. Duman published a study in 2020 in Pharmacology Biochemistry and Behavior regarding the neurotrophic mechanisms underlying the rapid and sustained antidepressant actions of ketamine.
referenceAlexandrine Corriger and Gisele Pickering published a narrative review in 2019 titled 'Ketamine and depression' in the journal Drug Design, Development and Therapy.
claimThere is a robust literature of studies establishing the safety and efficacy of ketamine-assisted treatment for depression (Salahudeen et al. 2020) and increasingly high-quality studies on psilocybin-based therapies for depression (Carhart-Harris et al. 2021; Davis et al. 2020), though larger and more robust clinical trials are still needed.
Neuroimaging in psychedelic drug development: past, present, and ... nature.com Sep 27, 2023 5 facts
claimWhile the authors focused their study outlines on 5-HT2AR agonist 'classic' psychedelics like psilocybin, LSD, and DMT, these study frameworks could be applied to other novel therapies such as ketamine, MDMA, and ibogaine.
claimNeuroplasticity is proposed as a convergent mechanism of action for both ketamine and classical psychedelics.
claimKetamine, 3,4-Methylenedioxymethamphetamine (MDMA), and ibogaine are psychoactive substances that hold promise for psychiatric treatment alongside classic serotonergic psychedelics.
referenceSumner RL, McMillan R, Spriggs MJ, Campbell D, Malpas G, Maxwell E, et al. authored 'Ketamine Enhances Visual Sensory Evoked Potential Long-term Potentiation in Patients With Major Depressive Disorder', published in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging in 2020, volume 5, pages 45–55.
claimModern research into classic psychedelics and related compounds includes the study of LSD, psilocybin, N,N-Dimethyltryptamine (DMT), MDMA, ketamine, and ibogaine.
Classification Schemes of Altered States of Consciousness - ORBi orbi.uliege.be 2 facts
referenceVollenweider, F.X., et al. (1997) published 'Metabolic hyperfrontality and psychopathology in the ketamine model of psychosis using positron emission tomography (PET) and [18F]fluorodeoxyglucose (FDG)' in European Neuropsychopharmacology, which investigates metabolic changes in the brain during ketamine-induced psychosis.
claimSchartner et al. (2017) reported that psychoactive doses of ketamine, LSD, and psilocybin lead to increased spontaneous MEG (magnetoencephalography) signal diversity.
Psychedelics, Sociality, and Human Evolution frontiersin.org 2 facts
claimThe NMDA antagonist ketamine and the 5-HT agonist psilocybin produce dissociable effects on the structural encoding of emotional face expressions.
referenceDe Gregorio et al. (2021a) reviewed preclinical and clinical studies on the use of hallucinogens, specifically LSD, psilocybin, MDMA, and ketamine, in mental health, published in the Journal of Neuroscience.
What Western medicine can learn from the ancient history of ... - BBC bbc.com Sep 11, 2024 2 facts
claimProponents of psychedelic-assisted therapy suggest that compounds like MDMA, LSD, psilocybin, and ketamine may help alter the perspectives of individuals suffering from 'diseases of despair'—such as suicide, drug overdose, and alcohol abuse—when used in conjunction with talking therapy.
claimModern medical researchers are investigating psychedelic compounds such as MDMA, LSD, psilocybin, and ketamine as potential treatments for psychiatric disorders including anxiety, depression, and substance abuse.
Psychedelics and Consciousness: Distinctions, Demarcations, and ... ouci.dntb.gov.ua 1 fact
claimSedatives (alcohol, zolpidem, triazolam), dissociatives (ketamine, dextromethorphan), psychedelics (psilocybin, MDMA), stimulants (dextroamphetamine, dextromethamphetamine), and cannabinoids (THC) each have idiosyncratic effects on episodic memory, differentially impairing certain mnemonic processes while sparing or facilitating others.
History and Current Status of Psychedelics and Entactogens ... - NCBI ncbi.nlm.nih.gov 1 fact
claimNon-classic hallucinogens include MDMA (also known as ecstasy or molly), ketamine, and ibogaine, according to Charles Grob.
Protocol for testing global neuronal workspace and integrated ... journals.plos.org 1 fact
procedureEuthanasia for mice is performed by infusion of ketamine (300 mg/kg) and dexmedetomidine (3 mg/kg) or prolonged exposure to CO2, consistent with American Veterinary Medical Association (AVMA) Guidelines on Euthanasia.
Psychedelic Drugs News - ScienceDaily sciencedaily.com 1 fact
claimA slow-release, tablet form of ketamine with minimal side-effects has the potential to make treatment more affordable.
DRUGS, RITUALS AND ALTERED STATES OF CONSCIOUSNESS semanticscholar.org 1 fact
referenceThe 2022 publication Frontiers in Psychology discusses psychotherapy involving the use of psychedelic substances, specifically identifying psilocybin, lysergic acid diethylamide (LSD), and ketamine as examples.
A Synergistic Workspace for Human Consciousness Revealed by ... elifesciences.org 1 fact
referenceThe study 'Consciousness and complexity during unresponsiveness induced by propofol, xenon, and ketamine' published in Current Biology examines consciousness and complexity in states of unresponsiveness induced by propofol, xenon, and ketamine.