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Ketamine

Clinical Applications of Hallucinogens: A Review

Abstract

Hallucinogens fall into several different classes, as broadly defined by pharmacological mechanism of action, and chemical structure. These include psychedelics, entactogens, dissociatives, and other atypical hallucinogens. Although these classes do not share a common primary mechanism of action, they do exhibit important similarities in their ability to occasion temporary but profound alterations of consciousness, involving acute changes in somatic, perceptual, cognitive, and affective processes. Such effects likely contribute to their recreational use. However, a growing body of evidence indicates that these drugs may have therapeutic applications beyond their potential for abuse. This review will present data on several classes of hallucinogens with a particular focus on psychedelics, entactogens, and dissociatives, for which clinical utility has been most extensively documented. Information on each class is presented in turn, tracing relevant historical insights, highlighting similarities and differences between the classes from the molecular to the behavioral level, and presenting the most up-to-date information on clinically oriented research with these substances, with important ramifications for their potential therapeutic value.

Garcia-Romeu, A., Kersgaard, B., & Addy, P. H. (2016). Clinical applications of hallucinogens: A review. Experimental and clinical psychopharmacology, 24(4), 229. 10.1037/pha0000084
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Ketamine abuse potential and use disorder

Abstract

Ketamine is a noncompetitive antagonist of N-methyl-d-asparate (NMDA) receptor and has been long used as an anesthetic agent in humans and veterinary medicine. The present article reviews the epidemiology, pharmacology, neurochemistry, and treatment of ketamine abuse. Ketamine has a unique mood controlling property and a number of studies have demonstrated a significant and rapid antidepressant effect of ketamine. However, the therapeutic value of ketamine to treat psychiatric disorders faces a major challenge that ketamine also owns significant reinforcing and toxic effects. Its abuse has posted severe harms on individuals and society. Disrupted learning and memory processing has long been related with ketamine use. It is hypothesized that ketamine blocks NMDA receptors on gamma-aminobutyric acid (GABA) neurons inside the thalamic reticular nucleus, which leads to disinhibition of dopaminergic neurons and increased release of dopamine. Currently, there is no specific treatment for treating every ketamine patient presenting peripheral toxicity. Interestingly, ketamine psychotherapy has been suggested to be a promising approach to treat addiction of other drugs. Future research can continue to develop creative ways to investigate potential mechanism and treatments related to ketamine abuse that have posted severe individual and social harms.

Liu, Y., Lin, D., Wu, B., & Zhou, W. (2016). Ketamine abuse potential and use disorder. Brain research bulletin. http://dx.doi.org/0.1016/j.brainresbull.2016.05.016
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Major Depressive Disorder Induced by Chronic Ketamine Abuse: A Case Report

Abstract

Ketamine, an NMDA (N-methyl-d-aspartate) glutamate antagonist, commonly used as an anesthetic agent, has emerged as a major substance of abuse particularly in Asia.1 Here, we present, to our knowledge, the first case of a patient who developed major depressive episodes after heavy and long-term ketamine use.

Chang, H., Huang, M. C., & Chen, L. Y. (2016). Major Depressive Disorder Induced by Chronic Ketamine Abuse: A Case Report. The Primary Care Companion for CNS Disorders, 18(3). 10.4088%2FPCC.15l01881
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Potential involvement of serotonergic signaling in ketamine’s antidepressant actions: A critical review

Abstract

A single i.v. infusion of ketamine, classified as an N-methyl-d-aspartate (NMDA) receptor antagonist, may alleviate depressive symptoms within hours of administration in treatment resistant depressed patients, and the antidepressant effect may last for several weeks. These unique therapeutic properties have prompted researchers to explore the mechanisms mediating the antidepressant effects of ketamine, but despite many efforts, no consensus on its antidepressant mechanism of action has been reached. Recent preclinical reports have associated the neurotransmitter serotonin (5-hydroxytryptamine; 5-HT) with the antidepressant-like action of ketamine. Here, we review the current evidence for a serotonergic role in ketamine’s antidepressant effects.

The pharmacological profile of ketamine may include equipotent activity on several non-NMDA targets, and the current hypotheses for the mechanisms responsible for ketamine’s antidepressant activity do not appear to preclude the possibility that non-glutamate neurotransmitters are involved in the antidepressant effects. At multiple levels, the serotonergic and glutamatergic systems interact, and such crosstalk could support the notion that changes in serotonergic neurotransmission may impact ketamine’s antidepressant potential. In line with these prospects, ketamine may increase 5-HT levels in the prefrontal cortex of rats, plausibly via hippocampal NMDA receptor inhibition and activation of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors. In addition, a number of preclinical studies suggest that the antidepressant-like effects of ketamine may depend on endogenous activation of 5-HT receptors. Recent imaging and behavioral data predominantly support a role for 5-HT1A or 5-HT1B receptors, but the full range of 5-HT receptors has currently not been systematically investigated in this context. Furthermore, the nature of any 5-HT dependent mechanism in ketamine’s antidepressant effect is currently not understood, and therefore, more studies are warranted to confirm this hypothesis and explore the specific pathways that might implicate 5-HT.

du Jardin, K. G., Müller, H. K., Elfving, B., Dale, E., Wegener, G., & Sanchez, C. (2016). Potential involvement of serotonergic signaling in ketamine’s antidepressant actions: A critical review. Progress in Neuro-Psychopharmacology and Biological Psychiatry. http://dx.doi.org/10.1016/j.pnpbp.2016.05.007
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Potential involvement of serotonergic signaling in ketamine's antidepressant actions: A critical review

Abstract

A single i.v. infusion of ketamine, classified as an N-methyl-d-aspartate (NMDA) receptor antagonist, may alleviate depressive symptoms within hours of administration in treatment resistant depressed patients, and the antidepressant effect may last for several weeks. These unique therapeutic properties have prompted researchers to explore the mechanisms mediating the antidepressant effects of ketamine, but despite many efforts, no consensus on its antidepressant mechanism of action has been reached. Recent preclinical reports have associated the neurotransmitter serotonin (5-hydroxytryptamine; 5-HT) with the antidepressant-like action of ketamine. Here, we review the current evidence for a serotonergic role in ketamine’s antidepressant effects.

The pharmacological profile of ketamine may include equipotent activity on several non-NMDA targets, and the current hypotheses for the mechanisms responsible for ketamine’s antidepressant activity do not appear to preclude the possibility that non-glutamate neurotransmitters are involved in the antidepressant effects. At multiple levels, the serotonergic and glutamatergic systems interact, and such crosstalk could support the notion that changes in serotonergic neurotransmission may impact ketamine’s antidepressant potential. In line with these prospects, ketamine may increase 5-HT levels in the prefrontal cortex of rats, plausibly via hippocampal NMDA receptor inhibition and activation of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors. In addition, a number of preclinical studies suggest that the antidepressant-like effects of ketamine may depend on endogenous activation of 5-HT receptors. Recent imaging and behavioral data predominantly support a role for 5-HT1A or 5-HT1B receptors, but the full range of 5-HT receptors has currently not been systematically investigated in this context. Furthermore, the nature of any 5-HT dependent mechanism in ketamine’s antidepressant effect is currently not understood, and therefore, more studies are warranted to confirm this hypothesis and explore the specific pathways that might implicate 5-HT.

du Jardin, K. G., Müller, H. K., Elfving, B., Dale, E., Wegener, G., & Sanchez, C. (2016). Potential involvement of serotonergic signaling in ketamine’s antidepressant actions: A critical review. Progress in Neuro-Psychopharmacology and Biological Psychiatry. http://dx.doi.org/10.1016/j.pnpbp.2016.05.007
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Efficacy and safety of oral ketamine versus diclofenac to alleviate mild to moderate depression in chronic pain patients: A double-blind, randomized, controlled trial

Abstract

Background: Ketamine is a glutamate N-methyl-d-aspartate receptor antagonist capable of exerting antidepressive effects in single or repeated intravenous infusions. The objective of this study was to investigate the safety and the efficacy of oral ketamine vs. diclofenac monotherapy in reducing symptoms of mild to moderate depression among patients with chronic pain.

Methods: This study is a 6-week, randomized, double-blind, controlled, parallel-group trial with two intervention arms (ketamine, fixed daily dosage of 150 mg vs. diclofenac, fixed daily dosage of 150 mg). Twenty participants in each arm completed the trial program all of whom had two post-baseline measurements at week 3 and week 6. Reduction in depression symptoms was assessed using the Hamilton Depression Rating Scale (HDRS) and the hospital anxiety and depression subscale for depression (HADSDepression) scores at baseline and week 3 and week 6 post-intervention.

Results: Significantly lower HDRS scores were observed in the ketamine treatment group as early as 6 weeks post-intervention (P=0.008). By comparison, mean (±standard deviation) HADS depression subscale scores were significantly lower for individuals receiving ketamine compared to diclofenac for both post-baseline measures at week 3 (6.95±1.47 vs. 8.40±1.6, P=0.005) and week 6 (6.20±1.15 vs. 7.35±1.18, p=0.003).

Limitations: The limitations of the present study were its small sample size and the short-term follow-up period.

Conclusions: Oral ketamine appears to be a safe and effective option in improving depressive symptoms of patients with chronic pain with mild-to-moderate depression.

Jafarinia, M., Afarideh, M., Tafakhori, A., Arbabi, M., Ghajar, A., Noorbala, A. A., … & Akhondzadeh, S. (2016). Efficacy and Safety of Oral Ketamine versus Diclofenac to Alleviate Mild to Moderate Depression in Chronic Pain Patients: A Double-Blind, Randomized, Controlled Trial. Journal of Affective Disorders. http://dx.doi.org/10.1016/j.jad.2016.05.076

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Ketamine for Treatment of Suicidal Ideation and Reduction of Risk for Suicidal Behavior

Abstract

Ketamine, an NMDA receptor antagonist with efficacy as a rapid anti-depressant, has early evidence for action to reduce suicidal ideation. This review will explore several important questions that arise from these studies. First, how do we measure reductions in suicidal ideation that occur over minutes to hours? Second, are the reductions in suicidal ideation after ketamine treatment solely a result of its rapid anti-depressant effect? Third, is ketamine only effective in reducing suicidal ideation in patients with mood disorders? Fourth, could ketamine’s action lead us to a greater understanding of the neurobiology of suicidal processes? Last, do the reductions in depression and suicidal ideation after ketamine treatment translate into decreased risk for suicidal behavior? Our review concludes that ketamine treatment can be seen as a double-edged sword, clinically to help provide treatment for acutely suicidal patients and experimentally to explore the neurobiological nature of suicidal ideation and suicidal behavior.

Mallick, F., & McCullumsmith, C. B. (2016). Ketamine for Treatment of Suicidal Ideation and Reduction of Risk for Suicidal Behavior. Current psychiatry reports, 18(6), 1-14. http://dx.doi.org/10.1007/s11920-016-0680-7
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Ethical Considerations for Clinical Research and Off-label Use of Ketamine to Treat Mood Disorders: The Balance between Risks and Benefits

Abstract

Tishler & Gordon (1999) highlighted ethical concerns behind challenge studies inducing psychosis with ketamine and made recommendations to enhance ethical standards. Recently, there is a plethora of clinical trials evaluating the efficacy of ketamine to treat mood disorders which lead to complex ethical issues. Pharmaceutical companies and researchers hope to profit by developing patentable variations on ketamine for treating depression. Media has labelled ketamine as a “miracle” antidepressant. Some clinics offer expensive off-label use of ketamine to treat mood disorders. This article examines the ecological validity of ketamine trials, measures to protect patients, informed consent procedures, financial inducements to participants and conflict of interest of researchers, therapeutic misconception, concealment and deception. Further recommendations are purposed to improve ethical standard of clinical research involving ketamine.

Zhang, M. W., & Ho, R. C. (2016). Ethical Considerations for Clinical Research and Off-label Use of Ketamine to Treat Mood Disorders: The Balance between Risks and Benefits. Ethics & Behavior. http://dx.doi.org/10.1080/10508422.2016.1189333
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Mood and neuropsychological effects of different doses of ketamine in electroconvulsive therapy for treatment-resistant depression

Abstract

BACKGROUND: Treatment-resistant depression (TRD) is a growing clinical challenge. Electroconvulsive therapy (ECT) is an effective tool for TRD treatment. However, there remains a subset of patients who do not respond to this treatment with common anesthetic agent. Ketamine, a noteworthy anesthetic agent, has emerged as an augmentation to enhance the antidepressant efficacy of ECT. Trials of i.v. ketamine in TRD indicated dose-related mood enhancing efficacy. We aimed to explore anesthetic and subanesthetic concentrations of ketamine in ECT for TRD with respect to their impact on mood and neuropsychological effects.
METHODS: Ninety TRD patients (36 males, 54 females; average age, 30.6 years old) were randomly assigned to receive either ketamine (0.8mg/kg) (n=30), subanesthetic ketamine (0.5mg/kg) plus propofol (0.5mg/kg) (n=30) or propofol (0.8mg/kg) (n=30) as an anesthetic and underwent 8 ECT sessions. The primary outcome measures were the 17-item Hamilton Depression Rating Scale (HDRS-17), cognitive assessments and seizure parameters.
RESULTS: The ketamine group had an earlier improvement in HDRS-17, longer seizure duration, lower electric quantity, a higher remission rate, and a lower degree of executive cognitive impairment compared to the ketamine+propofol and propofol groups. The ketamine+propofol group showed earlier improvement in the HDRS-17, a longer seizure duration and a different seizure energy index when compared to the propofol group.
LIMITATIONS: The postoperative dissociative side effect was not assessed.
CONCLUSIONS: Both anesthetic and subanesthetic concentrations of ketamine have rapid mood enhancing actions in ECT for TRD, while anesthetic concentrations results in larger magnitudes of antidepression and cognitive protection. ECT with ketamine anesthesia might be an optimized therapy for patients with TRD.
Zhong, X., He, H., Zhang, C., Wang, Z., Jiang, M., Li, Q., … & Huang, X. (2016). Mood and neuropsychological effects of different doses of ketamine in electroconvulsive therapy for treatment-resistant depression. Journal of Affective Disorders, 201, 124-130. http://dx.doi.org/10.1016/j.jad.2016.05.011
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Online Event - Psychedelic Care in Recreational Settings - 3 October 2024

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