OPEN Foundation

J. Murrough

Habenula Connectivity and Intravenous Ketamine in Treatment-Resistant Depression


Background: Ketamine’s potent and rapid antidepressant properties have shown great promise to treat severe forms of major depressive disorder (MDD). A recently hypothesized antidepressant mechanism of action of ketamine is the inhibition of N-methyl-D-aspartate receptor-dependent bursting activity of the habenula (Hb), a small brain structure that modulates reward and affective states.

Methods: Resting-state functional magnetic resonance imaging was conducted in 35 patients with MDD at baseline and 24 hours following treatment with i.v. ketamine. A seed-to-voxel functional connectivity (FC) analysis was performed with the Hb as a seed-of-interest. Pre-post changes in FC and the associations between changes in FC of the Hb and depressive symptom severity were examined.

Results: A reduction in Montgomery-Åsberg Depression Rating Scale scores from baseline to 24 hours after ketamine infusion was associated with increased FC between the right Hb and a cluster in the right frontal pole (t = 4.65, P = .03, false discovery rate [FDR]-corrected). A reduction in Quick Inventory of Depressive Symptomatology-Self Report score following ketamine was associated with increased FC between the right Hb and clusters in the right occipital pole (t = 5.18, P < .0001, FDR-corrected), right temporal pole (t = 4.97, P < .0001, FDR-corrected), right parahippocampal gyrus (t = 5.80, P = .001, FDR-corrected), and left lateral occipital cortex (t = 4.73, P = .03, FDR-corrected). Given the small size of the Hb, it is possible that peri-habenular regions contributed to the results.

Conclusions: These preliminary results suggest that the Hb might be involved in ketamine’s antidepressant action in patients with MDD, although these findings are limited by the lack of a control group.

Rivas-Grajales, A. M., Salas, R., Robinson, M. E., Qi, K., Murrough, J. W., & Mathew, S. J. (2021). Habenula Connectivity and Intravenous Ketamine in Treatment-Resistant Depression. The international journal of neuropsychopharmacology, 24(5), 383–391.

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Benefit-Risk Assessment of Esketamine Nasal Spray vs. Placebo in Treatment-Resistant Depression


This post hoc analysis assessed the benefit-risk profile of esketamine nasal spray + oral antidepressant (AD) induction and maintenance treatment in patients with treatment-resistant depression (TRD). The Benefit-Risk Action Team framework was utilized to assess the benefit-risk profile using data from three induction studies and one maintenance study. Benefits were proportion of remitters or responders in induction studies and proportion of stable remitters or stable responders who remained relapse-free in the maintenance study. Risks were death, suicidal ideation, most common adverse events (AEs), and potential long-term risks. Per 100 patients on esketamine + AD vs. AD + placebo in induction therapy, 5-21 additional patients would remit and 14-17 additional patients would respond. In maintenance therapy, 19-32 fewer relapses would occur with esketamine. In both cases, there was little difference in serious or severe common AEs (primarily dissociation, vertigo, and dizziness). These findings support a positive benefit-risk balance for esketamine + AD as induction and maintenance treatment in patients with TRD.
McIntyre, R. S., Rosenblat, J. D., Nemeroff, C. B., Sanacora, G., Murrough, J. W., Berk, M., … & Stahl, S. (2021). Synthesizing the Evidence for Ketamine and Esketamine in Treatment-Resistant Depression: An International Expert Opinion on the Available Evidence and Implementation. American Journal of Psychiatry, appi-ajp.,
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Ketamine for Depression: An Update


A decade has now passed since research into the antidepressant effects of ketamine began in earnest, after the clinical trial reported by Zarate et al. in 2006 (1). In that proof-of-concept study, 18 medication-free patients with treatment-resistant major depressive disorder (TRD) showed a large reduction in core depressive symptoms within hours of receiving a single low-dose 0.5 mg/kg intravenous infusion of ketamine as measured by the 21-item Hamilton Depression Rating Scale compared with saline placebo.

Murrough, J. W. (2016). Ketamine for Depression: An Update. Biological Psychiatry, 80(6), 416-418.
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Ketamine for treatment-resistant depression: recent developments and clinical applications


Approximately one-third of patients with major depressive disorder (MDD) do not respond to existing antidepressants, and those who do generally take weeks to months to achieve a significant effect. There is a clear unmet need for rapidly acting and more efficacious treatments. We will review recent developments in the study of ketamine, an old anaesthetic agent which has shown significant promise as a rapidly acting antidepressant in treatment-resistant patients with unipolar MDD, focusing on clinically important aspects such as dose, route of administration and duration of effect. Additional evidence suggests ketamine may be efficacious in patients with bipolar depression, post-traumatic stress disorder and acute suicidal ideation. We then discuss the safety of ketamine, in which most neuropsychiatric, neurocognitive and cardiovascular disturbances are short lasting; however, the long-term effects of ketamine are still unclear. We finally conclude with important information about ketamine for primary and secondary physicians as evidence continues to emerge for its potential use in clinical settings, underscoring the need for further investigation of its effects.

Schwartz, J., Murrough, J. W., & Iosifescu, D. V. (2016). Ketamine for treatment-resistant depression: recent developments and clinical applications. Evidence-based mental health.

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Current Status of Ketamine and Related Therapies for Mood and Anxiety Disorders


Major depressive disorder (MDD) is a leading cause of disability worldwide. Despite a plethora of established treatments, less than one third of individuals with MDD achieve stable remission of symptoms. Given limited efficacy and significant lag time to onset of therapeutic action among conventional antidepressants, interest has shifted to treatments that act outside of the monoamine neurotransmitter systems (e.g., serotonin, norepinephrine, and dopamine). Preclinical and clinical research on the glutamate system has been particularly promising in this regard. Accumulating evidence shows support for a rapid antidepressant effect of ketamine—a glutamate N-methyl-d-aspartate (NMDA) receptor antagonist. The present article reviews the pharmacology, safety, and efficacy of ketamine as a novel therapeutic agent for mood and anxiety disorders. The majority of clinical trials using ketamine have been conducted in patients with treatment-resistant forms of MDD; recent work has begun to examine ketamine in bipolar disorder, post-traumatic stress disorder, and obsessive–compulsive disorder. The impact of ketamine on suicidal ideation is also discussed. The current status and prospects for the identification of human biomarkers of ketamine treatment response and hurdles to treatment development are considered. We conclude by considering modulators of the glutamate system other than ketamine currently in development as potential novel treatment strategies for mood and anxiety disorders.

Costi, S., Van Dam, N. T., & Murrough, J. W. (2015). Current Status of Ketamine and Related Therapies for Mood and Anxiety Disorders. Current Behavioral Neuroscience Reports, 1-10.
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Regulation of neural responses to emotion perception by ketamine in individuals with treatment-resistant major depressive disorder


The glutamate N-methyl-D-aspartate receptor antagonist ketamine has demonstrated antidepressant effects in individuals with treatment-resistant major depressive disorder (TRD) within 24h of a single dose. The current study utilized functional magnetic resonance imaging (fMRI) and two separate emotion perception tasks to examine the neural effects of ketamine in patients with TRD. One task used happy and neutral facial expressions; the other used sad and neutral facial expressions. Twenty patients with TRD free of concomitant antidepressant medication underwent fMRI at baseline and 24h following administration of a single intravenous dose of ketamine (0.5mgkg−1). Adequate data were available for 18 patients for each task. Twenty age- and sex-matched healthy volunteers were scanned at one time point for baseline comparison. Whole-brain, voxel-wise analyses were conducted controlling for a family-wise error rate (FWE) of P<0.05. Compared with healthy volunteers, TRD patients showed reduced neural responses to positive faces within the right caudate. Following ketamine, neural responses to positive faces were selectively increased within a similar region of right caudate. Connectivity analyses showed that greater connectivity of the right caudate during positive emotion perception was associated with improvement in depression severity following ketamine. No main effect of group was observed for the sad faces task. Our results indicate that ketamine specifically enhances neural responses to positive emotion within the right caudate in depressed individuals in a pattern that appears to reverse baseline deficits and that connectivity of this region may be important for the antidepressant effects of ketamine.

Murrough, J. W., Collins, K. A., Fields, J., DeWilde, K. E., Phillips, M. L., Mathew, S. J., … & Iosifescu, D. V. (2015). Regulation of neural responses to emotion perception by ketamine in individuals with treatment-resistant major depressive disorder. Translational psychiatry, 5(2).
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Neurocognitive Effects of Ketamine and Association with Antidepressant Response in Individuals with Treatment-Resistant Depression: A Randomized Controlled Trial


The glutamate N-methyl-D-aspartate (NMDA) receptor antagonist ketamine displays rapid antidepressant effects in patients with treatment-resistant depression (TRD); however, the potential for adverse neurocognitive effects in this population has not received adequate study. The current study was designed to investigate the delayed neurocognitive impact of ketamine in TRD and examine baseline antidepressant response predictors in the context of a randomized controlled trial. In the current study, 62 patients (mean age=46.2±12.2) with TRD free of concomitant antidepressant medication underwent neurocognitive assessments using components of the MATRICS Consensus Cognitive Battery (MCCB) before and after a single intravenous infusion of ketamine (0.5mg/kg) or midazolam (0.045mg/kg). Participants were randomized to ketamine or midazolam in a 2:1 fashion under double-blind conditions and underwent depression symptom assessments at 24, 48, 72h, and 7 days post treatment using the Montgomery–Asberg Depression Rating Scale (MADRS). Post-treatment neurocognitive assessment was conducted once at 7 days. Neurocognitive performance improved following the treatment regardless of treatment condition. There was no differential effect of treatment on neurocognitive performance and no association with antidepressant response. Slower processing speed at baseline uniquely predicted greater improvement in depression at 24h following ketamine (t=2.3, p=0.027), while controlling for age, depression severity, and performance on other neurocognitive domains. In the current study, we found that ketamine was devoid of adverse neurocognitive effects at 7 days post treatment and that slower baseline processing speed was associated with greater antidepressant response. Future studies are required to further define the neurocognitive profile of ketamine in clinical samples and to identify clinically useful response moderators.

Murrough, J. W., Burdick, K. E., Levitch, C. F., Perez, A. M., Brallier, J. W., Chang, L. C., … & Iosifescu, D. V. (2014). Neurocognitive Effects of Ketamine and Association with Antidepressant Response in Individuals with Treatment-Resistant Depression: A Randomized Controlled Trial. Neuropsychopharmacology.

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


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.

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Efficacy of Intravenous Ketamine for Treatment of Chronic Posttraumatic Stress Disorder


Importance  Few pharmacotherapies have demonstrated sufficient efficacy in the treatment of posttraumatic stress disorder (PTSD), a chronic and disabling condition.

Objective  To test the efficacy and safety of a single intravenous subanesthetic dose of ketamine for the treatment of PTSD and associated depressive symptoms in patients with chronic PTSD.

Design, Setting, and Participants  Proof-of-concept, randomized, double-blind, crossover trial comparing ketamine with an active placebo control, midazolam, conducted at a single site (Icahn School of Medicine at Mount Sinai, New York, New York). Forty-one patients with chronic PTSD related to a range of trauma exposures were recruited via advertisements.

Interventions  Intravenous infusion of ketamine hydrochloride (0.5 mg/kg) and midazolam (0.045 mg/kg).

Main Outcomes and Measures  The primary outcome measure was change in PTSD symptom severity, measured using the Impact of Event Scale–Revised. Secondary outcome measures included the Montgomery-Asberg Depression Rating Scale, the Clinical Global Impression–Severity and –Improvement scales, and adverse effect measures, including the Clinician-Administered Dissociative States Scale, the Brief Psychiatric Rating Scale, and the Young Mania Rating Scale.

Results  Ketamine infusion was associated with significant and rapid reduction in PTSD symptom severity, compared with midazolam, when assessed 24 hours after infusion (mean difference in Impact of Event Scale–Revised score, 12.7 [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][95% CI, 2.5-22.8]; P = .02). Greater reduction of PTSD symptoms following treatment with ketamine was evident in both crossover and first-period analyses, and remained significant after adjusting for baseline and 24-hour depressive symptom severity. Ketamine was also associated with reduction in comorbid depressive symptoms and with improvement in overall clinical presentation. Ketamine was generally well tolerated without clinically significant persistent dissociative symptoms.

Conclusions and Relevance  This study provides the first evidence for rapid reduction in symptom severity following ketamine infusion in patients with chronic PTSD. If replicated, these findings may lead to novel approaches to the pharmacologic treatment of patients with this disabling condition.

Feder, A., Parides, M. K., Murrough, J. W., Perez, A. M., Morgan, J. E., Saxena, S., … & Charney, D. S. (2014). Efficacy of intravenous ketamine for treatment of chronic posttraumatic stress disorder: a randomized clinical trial. JAMA psychiatry, 71(6), 681-688.
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Antidepressant efficacy of ketamine in treatment-resistant major depression: a two-site randomized controlled trial


Synthesize and assess the available scientific evidence from the period 2008-2012 on interventions of demonstrated efficacy in the treatment and rehabilitation of adolescents and adults engaged in the problematic use of alcohol and other substances.

A systematic review was undertaken with search and analysis of national and international literature on the subject in Spanish and English in the main international databases: PubMed/MEDLINE, LILACS, Embase, PsycINFO, SciELO, the databases of the York University Centre for Reviews and Dissemination (DARE, ETS Database), the Cochrane Library, and other sources of gray literature. The search criteria included randomized clinical trials and systematic reviews but excluded observational studies, qualitative studies, and articles of poor methodological quality.

The final sample consisted of 69 studies. The psychosocial interventions shown to be effective were cognitive behavioral therapy, family interventions, self-help interventions using the Internet, couples behavioral therapy, community strengthening and family training, telephone monitoring and support, and integrated therapy for substance abuse disorder with anxiety and depression comorbidity. Pharmacological interventions of demonstrated effectiveness were acamprosate, lysergic acid diethylamide (LSD), and benzodiazepines in problematic alcohol use, as well as maintenance therapy with high-dose opioids.

The demonstrated effectiveness of psychosocial and pharmacological interventions is slight but significant. However, strongly multidisciplinary interventions that use a cognitive behavioral approach and the involvement of people close to the consumer, as well as some of the specific pharmacological interventions, have been shown to yield the best results in terms of indicators of abstinence and prevention of relapses.

Murrough, J. W., Iosifescu, D. V., Chang, L. C., Al Jurdi, R. K., Green, C. E., Perez, A. M., … Mathew, S. J. (2013). Antidepressant efficacy of ketamine in treatment-resistant major depression: a two-site randomized controlled trial. American Journal of Psychiatry, 170(10), 1134-1142.
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30 April - Q&A with Rick Strassman