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Ketamine

Ketamine and other potential glutamate antidepressants

Abstract

The need for rapid acting antidepressants is widely recognised. There has been much interest in glutamate mechanisms in major depressive disorder (MDD) as a promising target for the development of new antidepressants. A single intravenous infusion of ketamine, a N-methyl-daspartate (NMDA) receptor antagonist anaesthetic agent, can alleviate depressive symptoms in patients within hours of administration. The mechanism of action appears to be in part through glutamate release onto non-NMDA receptors including α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and metabotropic receptors. However these are also reported effects on 5-HT, dopamine and intracellular effects on the mammalian target of rapamycin (mTOR) pathway. The effects of SSRI (Selective Serotonin Reuptake Inhibitor) antidepressants may also involve alterations in NMDA function. The article reviews the effect of current antidepressants on NMDA and examines the efficacy and mechanism of ketamine. Response to ketamine is also discussed and comparison with other glutamate drugs including lamotrigine, amantadine, riluzole, memantine, traxoprodil, GLYX-13, MK-0657, RO4917523, AZD2066 and Coluracetam. Future studies need to link the rapid antidepressant effects seen with ketamine to inflammatory theories in MDD.

Dutta, A., McKie, S., & Deakin, J. W. (2014). Ketamine and other potential glutamate antidepressants. Psychiatry research, 225(1-2), 1-13. https://dx.doi.org/10.1016/j.psychres.2014.10.028

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Improvement in suicidal ideation after ketamine infusion: Relationship to reductions in depression and anxiety

Abstract

Objective

Suicide is a psychiatric emergency. Currently, there are no approved pharmacologic treatments for suicidal ideation. Ketamine is an N-methyl-D-aspartate (NMDA) receptor antagonist that rapidly reduces suicidal ideation as well as depression and anxiety, but the dynamic between these symptoms is not known. The aim of this analysis was to evaluate whether ketamine has an impact on suicidal thoughts, independent of depressive and anxiety symptoms.

Methods

133 patients with treatment-resistant depression (major depressive disorder or bipolar I/II disorder) received a single subanesthetic infusion of ketamine (0.5 mg/kg over 40 min). Post-hoc correlations and linear mixed models evaluated the relationship between suicidal ideation and depression and anxiety symptoms using the Hamilton Depression Rating Scale (HAMD), Scale for Suicidal Ideation (SSI), Beck Depression Inventory (BDI), and Hamilton Anxiety Rating Scale (HAMA) focusing on 230 min post-infusion.

Results

At 230 min post-infusion, correlations between changes in suicidal ideation and depression ranged from 0.23 to 0.44 (p < .05), accounting for up to 19% in the variance of ideation change. Correlations with anxiety ranged from 0.23 to 0.40 (p < .05), accounting for similar levels of variance. Ketamine infusion was associated with significant reductions in suicidal ideation compared to placebo, when controlling for the effects of ketamine on depression (F1,587 = 10.31, p = .001) and anxiety (F1,567 = 8.54, p = .004).

Conclusions

Improvements in suicidal ideation after ketamine infusion are related to, but not completely driven by, improvements in depression and anxiety. Investigation of the specific effects of ketamine on suicidal thoughts is warranted.

Ballard, E. D., Ionescu, D. F., Voort, J. L. V., Niciu, M. J., Richards, E. M., Luckenbaugh, D. A., … & Zarate, C. A. (2014). Improvement in suicidal ideation after ketamine infusion: relationship to reductions in depression and anxiety. Journal of psychiatric research, 58, 161-166. https://dx.doi.org/10.1016/j.jpsychires.2014.07.027

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Single Ketamine Infusion and Neurocognitive Performance in Bipolar Depression

Abstract

We estimated neurocognitive performance using the trail making test (TMT) and the Stroop color-word interference test before, and on the 3rd day after a single infusion of ketamine, in 18 bipolar depressed patients receiving mood-stabilizing drugs. The performance on all tests significantly improved on the 3rd day after ketamine infusion which correlated positively with baseline intensity of neuropsychological impairment and was not associated either with baseline intensity of depression or reduction of depressive symptoms after 3 or 7 days. The results suggest that in such population of patients, single ketamine infusion may improve neuropsychological performance independently of antidepressant effect.

Permoda-Osip, A., Kisielewski, J., Bartkowska-Sniatkowska, A., & Rybakowski, J. K. (2014). Single Ketamine Infusion and Neurocognitive Performance in Bipolar Depression. Pharmacopsychiatry. https://dx.doi.org/10.1055/s-0034-1394399

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Ketamine: Promising Path or False Prophecy in the Development of Novel Therapeutics for Mood Disorders?

Abstract

Large ‘real world’ studies demonstrating the limited effectiveness and slow onset of clinical response associated with our existing antidepressant medications has highlighted the need for the development of new therapeutic strategies for major depression and other mood disorders. Yet, despite intense research efforts, the field has had little success in developing antidepressant treatments with fundamentally novel mechanisms of action over the past six decades, leaving the field wary and skeptical about any new developments. However, a series of relatively small proof-of-concept studies conducted over the last 15 years has gradually gained great interest by providing strong evidence that a unique, rapid onset of sustained, but still temporally limited, antidepressant effects can be achieved with a single administration of ketamine. We are now left with several questions regarding the true clinical meaningfulness of the findings and the mechanisms underlying the antidepressant action. In this Circumspectives piece, Dr Sanacora and Dr Schatzberg share their opinions on these issues and discuss paths to move the field forward.

Sanacora, G., & Schatzberg, A. F. (2015). Ketamine: Promising Path or False Prophecy in the Development of Novel Therapeutics for Mood Disorders&quest. Neuropsychopharmacology, 40(2), 259-267. https://dx.doi.org/10.1038/npp.2014.261

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Ketamine and Rapid-Acting Antidepressants: A Window into a New Neurobiology for Mood Disorder Therapeutics

Abstract

Ketamine is the prototype for a new generation of glutamate-based antidepressants that rapidly alleviate depression within hours of treatment. Over the past decade, there has been replicated evidence demonstrating the rapid and potent antidepressant effects of ketamine in treatment-resistant depression. Moreover, preclinical and biomarker studies have begun to elucidate the mechanism underlying the rapid antidepressant effects of ketamine, offering a new window into the biology of depression and identifying a plethora of potential treatment targets. This article discusses the efficacy, safety, and tolerability of ketamine, summarizes the neurobiology of depression, reviews the mechanisms underlying the rapid antidepressant effects of ketamine, and discusses the prospects for next-generation rapid-acting antidepressants.

Abdallah, C. G., Sanacora, G., Duman, R. S., & Krystal, J. H. (2015). Ketamine and Rapid-Acting Antidepressants: A Window into a New Neurobiology for Mood Disorder Therapeutics. Medicine, 66. https://dx.doi.org/10.1146/annurev-med-053013-062946

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Anti-anhedonic effect of ketamine and its neural correlates in treatment-resistant bipolar depression

Abstract

Anhedonia—which is defined as diminished pleasure from, or interest in, previously rewarding activities—is one of two cardinal symptoms of a major depressive episode. However, evidence suggests that standard treatments for depression do little to alleviate the symptoms of anhedonia and may cause reward blunting. Indeed, no therapeutics are currently approved for the treatment of anhedonia. Notably, over half of patients diagnosed with bipolar disorder experience significant levels of anhedonia during a depressive episode. Recent research into novel and rapid-acting therapeutics for depression, particularly the noncompetitive N-Methyl-D-aspartate receptor antagonist ketamine, has highlighted the role of the glutamatergic system in the treatment of depression; however, it is unknown whether ketamine specifically improves anhedonic symptoms. The present study used a randomized, placebo-controlled, double-blind crossover design to examine whether a single ketamine infusion could reduce anhedonia levels in 36 patients with treatment-resistant bipolar depression. The study also used positron emission tomography imaging in a subset of patients to explore the neurobiological mechanisms underpinning ketamine’s anti-anhedonic effects. We found that ketamine rapidly reduced the levels of anhedonia. Furthermore, this reduction occurred independently from reductions in general depressive symptoms. Anti-anhedonic effects were specifically related to increased glucose metabolism in the dorsal anterior cingulate cortex and putamen. Our study emphasizes the importance of the glutamatergic system in treatment-refractory bipolar depression, particularly in the treatment of symptoms such as anhedonia.

Lally, N., Nugent, A. C., Luckenbaugh, D. A., Ameli, R., Roiser, J. P., & Zarate, C. A. (2014). Anti-anhedonic effect of ketamine and its neural correlates in treatment-resistant bipolar depression. Translational psychiatry, 4(10). https://dx.doi.org/10.1038/tp.2014.105

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The role of ketamine in treatment-resistant depression: a systematic review

Abstract

BACKGROUND:

At least 10-20% of the patients suffering from depression meet criteria for treatment-resistant depression (TRD). In the last decades, an important role of glutamate in mood modulation has been hypothesized and ketamine, a non noncompetitive antagonist of the N-methyl-D-aspartate (NMDA) receptors, has been demonstrated to be effective in both MDD and TRD. However, concerns emerged about the optimal dosage, and frequency of administration of this treatment.

METHODS:

aiming to systematically review the current literature focusing on the main pharmacological properties and impact of ketamine in TRD, a detailed literature search in PubMed/Medline and ScienceDirect databases was conducted. Twenty-four manuscripts including a total of 416 patients fulfilled inclusion criteria.

RESULTS:

Most studies demonstrated that the NMDA antagonist ketamine has rapid antidepressant effects in TRD patients, confirming the active role of glutamate in the pathophysiology of this complex condition. Ketamine has been demonstrated to be rapidly effective and was associated with a significant clinical improvement in depressive symptoms within hours after administration. Also, ketamine was also found to be effective in reducing suicidality in TRD samples.

LIMITATIONS:

The long-term efficacy of ketamine has not been investigated by most studies. The psychotomimetic properties may complicate the application of this pharmacological agent.

CONCLUSIONS:

Ketamine may be considered a valid and intriguing antidepressant option for the treatment of TRD. Further studies are needed to evaluate its long-term antidepressant efficacy in patients with TRD.

Serafini, G., H Howland, R., Rovedi, F., Girardi, P., & Amore, M. (2014). The Role of Ketamine in Treatment-Resistant Depression: A Systematic Review. Current neuropharmacology, 12(5), 444-461. https://dx.doi.org/10.2174/1570159X12666140619204251
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Blood d-serine levels as a predictive biomarker for the rapid antidepressant effects of the NMDA receptor antagonist ketamine

Excerpt from the content

The N-methyl-d-aspartate (NMDA) receptor antagonist ketamine is the most effective antidepressant drug for patients with treatment-resistant major depressive disorder (MDD) or bipolar disorder (BD) (Krystal et al. 2013). A single subanesthetic dose (0.5 mg/kg) of ketamine produces rapid antidepressant effects in up to two-thirds of patients with MDD and BD, and this effect can last for 7 days or more (Krystal et al. 2013; Zarate et al. 2012). However, the biochemical pathways defining the differences between patients who respond to ketamine and those who do not are currently unknown.

We read with great interest the article entitled “d-serine plasma concentration is a potential biomarker of (R,S)-ketamine antidepressant response in subjects with treatment-resistant depression,” by Moaddel et al. (2014). d-Serine acts as an endogenous, obligatory co-agonist at the NMDA receptor, and in their study, the authors reported that plasma levels of d-serine in the ketamine responder group (3.02 ± …

Hashimoto, K. (2014). Blood d-serine levels as a predictive biomarker for the rapid antidepressant effects of the NMDA receptor antagonist ketamine. Psychopharmacology, 231(20), 4081-4082. https://dx.doi.org/10.1007/s00213-014-3735-7

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Ketamine safety and tolerability in clinical trials for treatment-resistant depression

Abstract

OBJECTIVE: Ketamine has demonstrated rapid antidepressant effects in patients with treatment-resistant depression (TRD); however, the safety and tolerability of ketamine in this population have not been fully described. Herein we report the largest study to date of the safety, tolerability, and acceptability of ketamine in TRD.

METHOD: Data from 205 intravenous (IV) ketamine infusions (0.5 mg/kg over 40 minutes) in 97 participants with DSM-IV-defined major depressive disorder (MDD) were pooled from 3 clinical trials conducted between 2006 and 2012 at 2 academic medical centers. Safety and tolerability measures included attrition, adverse events (AEs), hemodynamic changes, and assessments of psychosis and dissociation.

RESULTS: The overall antidepressant response rate, defined as a ≥ 50% improvement in Montgomery-Asberg Depression Rating Scale score, was 67% (65 of 97 participants). Four of 205 infusions (1.95%) were discontinued due to AEs. The overall attrition rate was 3.1% (3 of 97). In the first 4 hours after the infusion, the most common general AEs were drowsiness, dizziness, poor coordination, blurred vision, and feeling strange or unreal. Approximately one third of individuals experienced protocol-defined hemodynamic changes. Ketamine resulted in small but significant increases in psychotomimetic and dissociative symptoms (all P <.05). There were no cases of persistent psychotomimetic effects, adverse medical effects, or increased substance use in a subgroup of patients with available long-term follow-up information.

CONCLUSIONS: In this relatively large group of patients with TRD, ketamine was safe and well tolerated. Further research investigating the safety of ketamine in severe and refractory depression is warranted.

Wan, L. B., Levitch, C. F., Perez, A. M., Brallier, J. W., Iosifescu, D. V., Chang, L. C., … & Murrough, J. W. (2014). Ketamine safety and tolerability in clinical trials for treatment-resistant depression. The Journal of clinical psychiatry. https://dx.doi.org/10.4088/JCP.13m08852

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Ketamine administration in depressive disorders: a systematic review and meta-analysis

Abstract

Introduction
Ketamine’s efficacy in depressive disorders has been established in several controlled trials. The aim of the present study was to determine whether or not ketamine administration significantly improves depressive symptomatology in depression and more specifically in major depressive disorder (MDD), bipolar depression, resistant depression (non-ECT studies), and as an anesthetic agent in electroconvulsive therapy (ECT) for resistant depression (ECT studies). Secondary outcomes were the duration of ketamine’s effect, the efficacy on suicidal ideations, the existence of a dose effect, and the safety/tolerance of the treatment.

Methods
Studies were included if they met the following criteria (without any language or date restriction): design: randomized controlled trials, intervention: ketamine administration, participants: diagnosis of depression, and evaluation of severity based on a validated scale. We calculated standardized mean differences (SMDs) with 95 % confidence intervals (CIs) for each study. We used fixed and random effects models. Heterogeneity was assessed using the I2 statistic.

Results
We included nine non-ECT studies in our quantitative analysis (192 patients with major depressive disorder and 34 patients with bipolar depression). Overall, depression scores were significantly decreased in the ketamine groups compared to those in the control groups (SMD = −0.99; 95 % CI −1.23, −0.75; p < 0.01). Ketamine’s efficacy was confirmed in MDD (resistant to previous pharmacological treatments or not) (SMD = −0.91; 95 % CI −1.19,−0.64; p < 0.01), in bipolar depression (SMD = −1.34; 95 % CI −1.94, −0.75), and in drug-free patients as well as patients under medication. Four ECT trials (118 patients) were included in our quantitative analysis. One hundred and three patients were diagnosed with major depressive disorder and 15 with bipolar depression. Overall, depression scores were significantly improved in the 58 patients receiving ketamine in ECT anesthesia induction compared to the 60 patients (SMD = −0.56; 95 % CI −1.10, −0.02; p = 0.04; I2 = 52.4 %). The duration of ketamine’s effects was assessed in only two non-ECT studies and seemed to persist for 2–3 days; this result needs to be confirmed. Three of four studies found significant decrease of suicidal thoughts and one found no difference between groups, but suicidal ideations were only studied by the suicide item of the depressive scales. It was not possible to determine a dose effect; 0.5 mg/kg was used in the majority of the studies. Some cardiovascular events were described (mostly transient blood pressure elevation that may require treatment), and ketamine’s use should remain cautious in patients with a cardiovascular history.

Conclusion
The present meta-analysis confirms ketamine’s efficacy in depressive disorders in non-ECT studies, as well as in ECT studies. The results of this first meta-analysis are encouraging, and further studies are warranted to detail efficacy in bipolar disorders and other specific depressed populations. Middle- and long-term efficacy and safety have yet to be explored. Extrapolation should be cautious: Patients included had no history of psychotic episodes and no history of alcohol or substance use disorders, which is not representative of all the depressed patients that may benefit from this therapy.

Fond, G., Loundou, A., Rabu, C., Macgregor, A., Lançon, C., Brittner, M. … Boyer, L. (2014). Ketamine administration in depressive disorders: a systematic review and meta-analysis. Psychopharmacology, 231, 3663-3676. http://dx.doi.org/10.1007/s00213-014-3664-5
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