A Randomized Controlled Trial of Repeated Ketamine Administration for Chronic Posttraumatic Stress Disorder

Entactogen Effects of Ketamine: A Reverse-Translational Study

OBJECTIVE

The authors sought to assess the prosocial, entactogen effects of ketamine.

METHODS

Pleasure from social situations was assessed in a sample of participants with treatment-resistant depression from randomized, double-blind, placebo-controlled studies, using four items of the Snaith-Hamilton Pleasure Scale (SHAPS) at five time points over 1 week following treatment with ketamine (0.5 mg/kg intravenously) or placebo. The primary endpoint was postinfusion self-reported pleasure on the four SHAPS items pertaining to social situations, including the item on helping others, between the ketamine and placebo groups. In a rodent experiment, the impact of ketamine on helping behavior in rats was assessed using the harm aversion task. The primary endpoint was a reduction in lever response rate relative to baseline, which indicated the willingness of rats to forgo obtaining sucrose to help protect their cage mate from electric shock.

RESULTS

Relative to placebo, ketamine increased ratings of feeling pleasure from being with family or close friends, seeing other people's smiling faces, helping others, and receiving praise, for 1 week following treatment. In the rodent experiment, during the harm aversion task, ketamine-treated rats maintained lower response rates relative to baseline to a greater extent than what was observed in vehicle-treated rats for 6 days posttreatment and delivered fewer shocks overall.

CONCLUSIONS

In patients with treatment-resistant depression, ketamine treatment was associated with increased pleasure from social situations, such as feeling pleasure from helping others. Ketamine-treated rats were more likely to protect their cage mate from harm, at the cost of obtaining sucrose. These findings suggest that ketamine has entactogen effects.

Advancements in addressing drug dependence: A review of promising therapeutic strategies and interventions

Substance dependence represents a pervasive global concern within the realm of public health. Presently, it is delineated as a persistent and recurrent neurological disorder stemming from drug-triggered neuroadaptations in the brain's reward circuitry. Despite the availability of various therapeutic modalities, there has been a steady escalation in the mortality rate attributed to drug overdoses. Substantial endeavors have been directed towards the exploration of innovative interventions aimed at mitigating cravings and drug-induced repetitive behaviors. Within this review, we encapsulate the most auspicious contemporary treatment methodologies, accentuating meta-analyses of efficacious pharmacological and non-pharmacological approaches: including gabapentin, topiramate, prazosin, physical exercise regimens, and cerebral stimulation techniques.

Ketamine-assisted buprenorphine initiation: a pilot case series

BACKGROUND

Many people with opioid use disorder who stand to benefit from buprenorphine treatment are unwilling to initiate it due to experience with or fear of both spontaneous and buprenorphine-precipitated opioid withdrawal (BPOW). An effective means of minimizing withdrawal symptoms would reduce patient apprehensiveness, lowering the barrier to buprenorphine initiation. Ketamine, approved by the FDA as a dissociative anesthetic, completely resolved BPOW in case reports when infused at a sub-anesthetic dose range in which dissociative symptoms are common. However, most patients attempt buprenorphine initiation in the outpatient setting where altered mental status is undesirable. We explored the potential of short-term use of ketamine, self-administered sublingually at a lower, sub-dissociative dose to assist ambulatory patients undergoing transition to buprenorphine from fentanyl and methadone.

METHODS

Patients prescribed ketamine were either (1) seeking transition to buprenorphine from illicit fentanyl and highly apprehensive of BPOW or (2) undergoing transition to buprenorphine from illicit fentanyl or methadone and experiencing BPOW. We prescribed 4-8 doses of sublingual ketamine 16 mg (each dose bioequivalent to 3-6% of an anesthetic dose), monitored patients daily or near-daily, and adjusted buprenorphine and ketamine dosing based on patient response and prescriber experience.

RESULTS

Over a period of 14 months, 37 patients were prescribed ketamine. Buprenorphine initiation was completed by 16 patients, representing 43% of the 37 patients prescribed ketamine, and 67% of the 24 who reported trying it. Of the last 12 patients who completed buprenorphine initiation, 11 (92%) achieved 30-day retention in treatment. Most of the patients who tried ketamine reported reduction or elimination of spontaneous opioid withdrawal symptoms. Some patients reported avoidance of severe BPOW when used prophylactically or as treatment of established BPOW. We developed a ketamine protocol that allowed four of the last patients to complete buprenorphine initiation over four days reporting only mild withdrawal symptoms. Two patients described cognitive changes from ketamine at a dose that exceeded the effective dose range for the other patients.

CONCLUSIONS

Ketamine at a sub-dissociative dose allowed completion of buprenorphine initiation in the outpatient setting in the majority of patients who reported trying it. Further research is warranted to confirm these results and develop reliable protocols for a range of treatment settings.

Combined Effects of Nasal Ketamine and Trauma-Focused Psychotherapy in Treatment-Resistant Post-Traumatic Stress Disorder: A Pilot Case Series

OBJECTIVE

This pilot case series investigated the feasibility and efficacy of an eight-week therapy program, combining nasally administered ketamine (0.5 mg/kg) with trauma-focused psychotherapy, for individuals with chronic, treatment-resistant post-traumatic stress disorder (PTSD).

METHOD

Three patients with chronic, treatment-resistant PTSD underwent the eight-week therapy program. Clinical assessments included the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) and the Hamilton Depression Rating Scale (HAMD) at baseline, post-assessment, and follow-up assessment, along with additional measures assessing other relevant symptoms and side effects.

RESULTS

The results demonstrated clinically relevant reductions in PTSD symptoms, indicated by a change in the CAPS-5 score at post-assessment (M = -18.00; SE = 6.48) and follow-up assessment (M = -25.33, SE = 5.58). Additionally, depressive symptoms showed notable improvement, with changes in HAMD scores at post-assessment (M = -8.33, SE = 3.07) and follow-up assessment (M = -9.00, SE = 3.77). Positive effects were also observed in anxiety reduction, decreased dissociations, and improvements in emotion regulation and disturbances of self-organization.

CONCLUSIONS

Despite potential variations in clinical profiles among the patients, the therapy program demonstrated positive outcomes for all participants. Nasally administered ketamine was well tolerated and resulted in immediate symptom reduction in tension, anxiety, and common PTSD symptoms. However, to validate these findings and compare treatment efficacy, future randomized controlled trials are warranted, especially in comparison with trauma-focused therapy alone.

Neurobiology and Treatment of Posttraumatic Stress Disorder

The recent worldwide surge of warfare and hostilities exposes increasingly large numbers of individuals to traumatic events, placing them at risk of developing posttraumatic stress disorder (PTSD) and challenging both clinicians and service delivery systems. This overview summarizes and updates the core knowledge of the genetic, molecular, and neural circuit features of the neurobiology of PTSD and advances in evidence-based psychotherapy, pharmacotherapy, neuromodulation, and digital treatments. While the complexity of the neurobiology and the biological and clinical heterogeneity of PTSD have challenged clinicians and researchers, there is an emerging consensus concerning the underlying mechanisms and approaches to diagnosis, treatment, and prevention of PTSD. This update addresses PTSD diagnosis, prevalence, course, risk factors, neurobiological mechanisms, current standard of care, and innovations in next-generation treatment and prevention strategies. It provides a comprehensive summary and concludes with areas of research for integrating advances in the neurobiology of the disorder with novel treatment and prevention targets.

Ketamine-enhanced prolonged exposure therapy in veterans with PTSD: A randomized controlled trial protocol

BACKGROUND

The 2023 VA/DoD Clinical Practice Guideline for the Management of PTSD recommends individual, manualized trauma-focused such as Prolonged Exposure (PE) over pharmacologic interventions for the primary treatment of PTSD. Unfortunately, clinical trials of trauma-based therapies in the military and veteran population showed that 30% to 50% of patients did not demonstrate clinically meaningful symptom change. Ketamine, an FDA-approved anesthetic with potent non-competitive glutamatergic N-methyl-d-aspartate antagonistic properties, has demonstrated to enhance the recall of extinction learning and decrease fear renewal without interference of extinction training in preclinical studies.

METHODS

We plan to conduct a single site RCT comparing three ketamine treatment vs. active placebo (midazolam) adjunct to PE therapy among Veterans with PTSD. Pharmacological phase will start simultaneously with PE session 1. Infusions will be administered 24 h. prior to PE session for the first 3 weeks. After PE is completed (session 10), patients will be assessed during a 3-month follow-up period at various time points. We estimate that out of 100 veterans, 80 will reach time point for primary outcome measure and will be considered for primary analysis. Secondary outcomes include severity of depression and anxiety scores, safety and tolerability of ketamine-enhanced PE therapy, cognitive performance during treatment and early improvement during PE related to the rate of dropouts during PE therapy.

DISCUSSION

Results of the proposed RCT could provide scientific foundation to distinguish the essential components of this approach, enhance the methodology, elucidate the mechanisms involved, and identify sub-PTSD populations that most likely benefit from this intervention.

Potential effect of ketamine in treatment for dextromethorphan use disorder exploding in Japanese young population

In Japan, the landscape of clinical practice for substance use disorder is changing significantly, primarily due to an increase in patients using over-the-counter drugs. A major concern is the rising number of patients misusing dextromethorphan (DXM). These patients with DXM use disorders often have severe trauma-related and mood symptoms, and therefore try to cope with those symptoms by self-medicating with DXM. In this article, we propose that ketamine, which has similar psychopharmacological effects to DXM, may be a useful alternative pharmacological treatment for these patients.

Treatment Approaches for Posttraumatic Stress Disorder Derived From Basic Research on Fear Extinction

This brief review article will describe treatment approaches for posttraumatic stress disorder (PTSD) based on findings from basic research. The focus of this review will be fear conditioning and extinction models, which provide a translational model of PTSD that can help translate basic research in nonhuman animals through well-controlled trials confirming the efficacy of treatment approaches in humans with PTSD such as prolonged exposure therapy. Specific cognitive aspects of fear extinction processes, including consolidation and reconsolidation, are reviewed along with behavioral and pharmacological treatment strategies based on basic research in these areas including attempts to prevent the development of PTSD as well as the treatment of chronic PTSD. Pharmacological, behavioral, and device-based augmentation strategies of PTSD treatment based in basic science findings are reviewed, including those that disrupt noradrenergic receptor processes, medications that act on NMDA receptors, physical exercise, cannabinoids, estradiol, dexamethasone, yohimbine, losartan, dopamine, and MDMA, along with the evidence for their efficacy in human clinical samples. While fear extinction provides an exciting translational opportunity to improve PTSD based on basic science findings, we review limitations and challenges of the extant literature as well as future directions.

Ketamine ameliorates post-traumatic social avoidance by erasing the traumatic memory encoded in VTA-innervated BLA engram cells

Erasing traumatic memory during memory reconsolidation is a promising retrieval-extinction strategy for post-traumatic stress disorder (PTSD). Here, we developed an acute social defeat stress (SDS) mouse model with short-term and re-exposure-evoked long-term social avoidance. SDS-associated traumatic memories were identified to be stored in basolateral amygdala (BLA) engram cells. A single intraperitoneal administration of subanesthetic-dose ketamine within, but not beyond, the re-exposure time window significantly alleviates SDS-induced social avoidance, which reduces the activity and quantity of reactivated BLA engram cells. Furthermore, activation or inhibition of dopaminergic projections from the ventral tegmental area to the BLA effectively mimics or blocks the therapeutic effect of re-exposure with ketamine and is dopamine D2 receptor dependent. Single-cell RNA sequencing reveals that re-exposure with ketamine triggered significant changes in memory-related pathways in the BLA. Together, our research advances the understanding of how ketamine mitigates PTSD symptoms and offers promising avenues for developing more effective treatments for trauma-related disorders.

The Impact of Ketamine for Treatment of Post-Traumatic Stress Disorder: A Systematic Review With Meta-Analyses

BACKGROUND

Ketamine has been used in anesthesia, pain management, and major depressive disorder. It has recently been studied in patients with post-traumatic stress disorder (PTSD).

OBJECTIVE

To determine the impact of ketamine on PTSD symptomatology and depression scores.

METHODS

We conducted a literature search of Medline 1960 to May 20, 2023, and found 6 randomized controlled trials that met our inclusion criteria. We extracted data on the Clinician-Administered PTSD (CAPS), PTSD Checklist (PCL), or Montgomery-Asberg Depression Rating (MADRS) scales.

RESULTS

The use of ketamine significantly reduced CAPS scores (n = 5, MD: -10.63 [95% CI -14.95 to -6.32]), PCL scores (n = 3, MD: -6.13 [95% CI -8.61 to -3.64]), and MADRS scores (n = 3, MD: -6.33 [95% CI -8.97 to -3.69]) at the maximal follow-up times versus control. Significant benefits were found at day 1 and weeks 1, 2, and 4 for CAPS and PCL scores as well as MADRS scores at day 1, week 1, and week 4 for ketamine versus control. The time to PTSD relapse was prolonged in the patients receiving ketamine versus control (n = 2, 15.74 days [95% CI 3.57 to 29.91 days]). More dry mouth (n = 2, OR 5.85 [95% CI 1.32 to 25.95]), dizziness (n = 2, OR 3.83 [95% CI 1.28 to 11.41]), and blurred vision (n = 2, OR 7.57 [1.00 to 57.10]) occurred with ketamine than control therapy.

CONCLUSIONS AND RELEVANCE

Ketamine modestly reduced PTSD and depression scores as early as 1 day of therapy, but the longevity of effect needs to be determined. Given similar magnitude of benefit with SSRIs and venlafaxine, ketamine would not supplant these traditional options for chronic use.

[Pharmacological treatment of posttraumatic stress disorder]

In addition to trauma-focussed psychotherapy, pharmacological treatment is often unavoidable, especially in patients with severe posttraumatic stress disorder (PTSD). As long as comorbid disorders do not dictate the pharmacotherapy approach, sertraline and paroxetine, along with other off-label prescribable substances approved in Germany, can be used for the treatment of PTSD. Venlafaxine, in particular, has shown good effectiveness in studies, whereas risperidone has shown lower effectiveness in augmentation. Overall, only a small to medium effect size is to be expected for all substances. Psychopharmacotherapy plays an important role in addressing sleep disorders, which are highly prevalent in PTSD. Treatment of trauma-related nightmares can be attempted with doxazosin or clonidine. In contrast, there are limited empirical data available for sleep disorders associated with PTSD, but the pharmacological treatment of insomnia can provide some guidance.

Post-traumatic stress disorder: the role of the amygdala and potential therapeutic interventions - a review

Introduction

Post-traumatic stress disorder (PTSD) is a psychiatric disorder triggered by exposure to a life-threatening or sexually violent traumatic event, and is characterized by symptoms involving intrusive re-experiencing, persistent avoidance of associated stimuli, emotional and cognitive disturbances, and hyperarousal for long periods after the trauma has occurred. These debilitating symptoms induce occupational and social impairments that contribute to a significant clinical burden for PTSD patients, and substantial socioeconomic costs, reaching approximately $20,000 dollars per individual with PTSD each year in the US. Despite increased translational research focus in the field of PTSD, the development of novel, effective pharmacotherapies for its treatment remains an important unmet clinical need.

Observations

In this review, we summarize the evidence implicating dysfunctional activity of the amygdala in the pathophysiology of PTSD. We identify the transient receptor potential canonical (TRPC) ion channels as promising drug targets given their distribution in the amygdala, and evidence from animal studies demonstrating their role in fear response modulation. We discuss the evidence-based pharmacotherapy and psychotherapy treatment approaches for PTSD.

Discussion

In view of the prevalence and economic burden associated with PTSD, further investigation is warranted into novel treatment approaches based on our knowledge of the involvement of brain circuitry and the role of the amygdala in PTSD, as well as the potential added value of combined pharmacotherapy and psychotherapy to better manage PTSD symptoms.

Repurposing Ketamine in the Therapy of Depression and Depression-Related Disorders: Recent Advances and Future Potential

Depression represents a prevalent and enduring mental disorder of significant concern within the clinical domain. Extensive research indicates that depression is very complex, with many interconnected pathways involved. Most research related to depression focuses on monoamines, neurotrophic factors, the hypothalamic-pituitary-adrenal axis, tryptophan metabolism, energy metabolism, mitochondrial function, the gut-brain axis, glial cell-mediated inflammation, myelination, homeostasis, and brain neural networks. However, recently, Ketamine, an ionotropic N-methyl-D-aspartate (NMDA) receptor antagonist, has been discovered to have rapid antidepressant effects in patients, leading to novel and successful treatment approaches for mood disorders. This review aims to summarize the latest findings and insights into various signaling pathways and systems observed in depression patients and animal models, providing a more comprehensive view of the neurobiology of anxious-depressive-like behavior. Specifically, it highlights the key mechanisms of ketamine as a rapid-acting antidepressant, aiming to enhance the treatment of neuropsychiatric disorders. Moreover, we discuss the potential of ketamine as a prophylactic or therapeutic intervention for stress-related psychiatric disorders.

Molecular signatures of astrocytes and microglia maladaptive responses to acute stress are rescued by a single administration of ketamine in a rodent model of PTSD

Stress affects the brain and alters its neuroarchitecture and function; these changes can be severe and lead to psychiatric disorders. Recent evidence suggests that astrocytes and microglia play an essential role in the stress response by contributing to the maintenance of cerebral homeostasis. These cells respond rapidly to all stimuli that reach the brain, including stressors. Here, we used a recently validated rodent model of post-traumatic stress disorder in which rats can be categorized as resilient or vulnerable after acute inescapable footshock stress. We then investigated the functional, molecular, and morphological determinants of stress resilience and vulnerability in the prefrontal cortex, focusing on glial and neuronal cells. In addition, we examined the effects of a single subanesthetic dose of ketamine, a fast-acting antidepressant recently approved for the treatment of resistant depression and proposed for other stress-related psychiatric disorders. The present results suggest a prompt glial cell response and activation of the NF-κB pathway after acute stress, leading to an increase in specific cytokines such as IL-18 and TNF-α. This response persists in vulnerable individuals and is accompanied by a significant change in the levels of critical glial proteins such as S100B, CD11b, and CX43, brain trophic factors such as BDNF and FGF2, and proteins related to dendritic arborization and synaptic architecture such as MAP2 and PSD95. Administration of ketamine 24 h after the acute stress event rescued many of the changes observed in vulnerable rats, possibly contributing to support brain homeostasis. Overall, our results suggest that pivotal events, including reactive astrogliosis, changes in brain trophic factors, and neuronal damage are critical determinants of vulnerability to acute traumatic stress and confirm the therapeutic effect of acute ketamine against the development of stress-related psychiatric disorders.

Ketamine's Amelioration of Fear Extinction in Adolescent Male Mice Is Associated with the Activation of the Hippocampal Akt-mTOR-GluA1 Pathway

Fear-related disorders, including post-traumatic stress disorder (PTSD), and anxiety disorders are pervasive psychiatric conditions marked by persistent fear, stemming from its dysregulated acquisition and extinction. The primary treatment for these disorders, exposure therapy (ET), relies heavily on fear extinction (FE) principles. Adolescence, a vulnerable period for developing psychiatric disorders, is characterized by neurobiological changes in the fear circuitry, leading to impaired FE and increased susceptibility to relapse following ET. Ketamine, known for relieving anxiety and reducing PTSD symptoms, influences fear-related learning processes and synaptic plasticity across the fear circuitry. Our study aimed to investigate the effects of ketamine (10 mg/kg) on FE in adolescent male C57 BL/6 mice at the behavioral and molecular levels. We analyzed the protein and gene expression of synaptic plasticity markers in the hippocampus (HPC) and prefrontal cortex (PFC) and sought to identify neural correlates associated with ketamine's effects on adolescent extinction learning. Ketamine ameliorated FE in the adolescent males, likely affecting the consolidation and/or recall of extinction memory. Ketamine also increased the Akt and mTOR activity and the GluA1 and GluN2A levels in the HPC and upregulated BDNF exon IV mRNA expression in the HPC and PFC of the fear-extinguished mice. Furthermore, ketamine increased the c-Fos expression in specific brain regions, including the ventral HPC (vHPC) and the left infralimbic ventromedial PFC (IL vmPFC). Providing a comprehensive exploration of ketamine's mechanisms in adolescent FE, our study suggests that ketamine's effects on FE in adolescent males are associated with the activation of hippocampal Akt-mTOR-GluA1 signaling, with the vHPC and the left IL vmPFC as the proposed neural correlates.

Virtual realities, real recoveries: exploring the efficacy of 3MDR therapy for treatment-resistant PTSD

Exposure-based therapies have shown promise in treating post-traumatic stress disorder (PTSD), but challenges exist in maintaining patient engagement and finding appropriate stimuli for graded exposure. Virtual reality (VR) technology has been used to enhance exposure therapy, but current software lacks customization and some patients remain treatment-resistant. A novel approach called multimodular motion-assisted memory desensitization and reconsolidation (3MDR) has the potential to solve some of the current limitations of VR-assisted exposure therapy. This study examines the efficacy of 3MDR treatment for individuals with treatment-resistant PTSD through a systematic review of relevant literature and clinical studies. Preliminary findings indicate promise for 3MDR in reducing PTSD symptoms, including emotional regulation and moral injury. However, further research with larger samples and controlled studies is needed to understand underlying mechanisms and validate these results. Moreover, this study highlights the importance of health-economic evaluations to assess costs and resource utilization associated with implementing 3MDR treatment in clinical services.

Perspectives in treatment-resistant depression: esketamine and electroconvulsive therapy

Modern electroconvulsive therapy (ECT) and the approval of nasal esketamine for clinical use have significantly improved the approach to treatment-resistant depression (TRD), which is defined as non-response to at least two different courses of antidepressants with verified adherence to treatment, adequate dosage, and duration of treatment. The goal of this literature review is to present the newest evidence regarding efficacy and safety. Furthermore, we aim to provide an overview of future perspectives in this field of research, for example, regarding structural and molecular effects. Both treatment methods will be critically evaluated for their individual advantages, disadvantages, and response rates. Firstly, we will discuss the well-established method of ECT and its different treatment modalities. Secondly, we will discuss the properties of ketamine, the discovery of its antidepressive effects and the route to clinical approval of the esketamine nasal spray. We will comment on research settings which have evaluated intravenous ketamine against ECT. The decision-making process between esketamine nasal spray or ECT should include the assessment of contraindications, age, severity of disease, presence of psychotic symptoms, patient preference and treatment accessibility. We conclude that both treatment options are highly effective in TRD. If both are indicated, pragmatically esketamine will be chosen before ECT; however, ECT studies in ketamine non-responders are missing.

Healing wounded trees: clinicians' perspectives on treatment of complex posttraumatic stress disorder

While treatment guidelines agree on the first-line interventions for the treatment of posttraumatic stress disorder (PTSD), there is an ongoing debate between experts regarding the treatment of complex posttraumatic stress disorder (C-PTSD). As scientific research is slowly emerging, different treatment approaches are used in clinical practice This article aims to provide a set of treatment options for C-PTSD in adult survivors of repeated exposure to severe violence and abuse, both in childhood and later on in life. The developmental-contextual perspective on mental health forms the basis of this approach. This perspective is elaborated using the tree metaphor. Then, several treatment strategies are suggested. The presented strategies are a combination of the existing evidence-based approaches for the treatment of PTSD and personality disorders. They target psychological damage in survivors while taking their developmental trajectories and ecological environments into consideration. The treatment model presented is based on longstanding clinical practice and it may be a promising framework for treating C-PTSD. However, it still needs to be scientifically examined for acceptability and effectiveness.

Psychedelic Therapy: A Primer for Primary Care Clinicians-Ketamine

BACKGROUND

Ketamine, an arylcyclohexylamine dissociative anesthetic agent, has evolved into a versatile therapeutic. It has a rapid-onset, well-understood cardiovascular effects and a favorable safety profile in clinical use. Its enantiomeric compound, esketamine, was approved by the Food and Drug Administration in 2019 for both treatment-resistant depression and major depressive disorder with suicidal ideation.

AREAS OF UNCERTAINTY

Research indicates dose-dependent impacts on cognition, particularly affecting episodic and working memory following both acute administration and chronic use, albeit temporarily for the former and potentially persistent for the latter. Alongside acute risks to cardiovascular stability, ketamine use poses potential liver toxicity concerns, especially with prolonged or repeated exposure within short time frames. The drug's association with "ketamine cystitis," characterized by bladder inflammation, adds to its profile of physiological risks.

THERAPEUTIC ADVANCES

Data demonstrate a single intravenous infusion of ketamine exhibits antidepressant effects within hours (weighted effect size averages of depression scores (N = 518) following a single 0.5 mg/kg infusion of ketamine is d = 0.96 at 24 hours). Ketamine is also effective at reducing posttraumatic stress disorder (PTSD) symptom severity following repeated infusions (Clinician-Administered PTSD Scale scores: -11.88 points compared with midazolam control). Ketamine also decreased suicidal ideation in emergency settings (Scale for Suicidal Ideation scores: -4.96 compared with midazolam control). Through its opioid-sparing effect, ketamine has revolutionized postoperative pain management by reducing analgesic consumption and enhancing recovery.

LIMITATIONS

Many studies indicate that ketamine's therapeutic effects may subside within weeks. Repeated administrations, given multiple times per week, are often required to sustain decreases in suicidality and depressive symptoms.

CONCLUSIONS

Ketamine's comprehensive clinical profile, combined with its robust effects on depression, suicidal ideation, PTSD, chronic pain, and other psychiatric conditions, positions it as a substantial contender for transformative therapeutic application.

Effects of a dissociative drug on fronto-limbic resting-state functional connectivity in individuals with posttraumatic stress disorder: a randomized controlled pilot study

RATIONALE

A subanesthetic dose of ketamine, a non-competitive N-methyl-D-aspartate glutamate receptor (NMDAR) antagonist, elicits dissociation in individuals with posttraumatic stress disorder (PTSD), who also often suffer from chronic dissociative symptoms in daily life. These debilitating symptoms have not only been linked to worse PTSD trajectories, but also to increased resting-state functional connectivity (RSFC) between medial prefrontal cortex (mPFC) and amygdala, supporting the conceptualization of dissociation as emotion overmodulation. Yet, as studies were observational, causal evidence is lacking.

OBJECTIVES

The present randomized controlled pilot study examines the effect of ketamine, a dissociative drug, on RSFC between mPFC subregions and amygdala in individuals with PTSD.

METHODS

Twenty-six individuals with PTSD received either ketamine (0.5mg/kg; n = 12) or the control drug midazolam (0.045mg/kg; n = 14) during functional magnetic resonance imaging (fMRI). RSFC between amygdala and mPFC subregions, i.e., ventromedial PFC (vmPFC), dorsomedial PFC (dmPFC) and anterior-medial PFC (amPFC), was assessed at baseline and during intravenous drug infusion.

RESULTS

Contrary to pre-registered predictions, ketamine did not promote a greater increase in RSFC between amygdala and mPFC subregions from baseline to infusion compared to midazolam. Instead, ketamine elicited a stronger transient decrease in vmPFC-amygdala RSFC compared to midazolam.

CONCLUSIONS

A dissociative drug did not increase fronto-limbic RSFC in individuals with PTSD. These preliminary experimental findings contrast with prior correlative findings and call for further exploration and, potentially, a more differentiated view on the neurobiological underpinning of dissociative phenomena in PTSD.

A Neuroanatomic and Pathophysiologic Framework for Novel Pharmacological Approaches to the Treatment of Post-traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is a debilitating disorder inflicting high degrees of symptomatic and socioeconomic burdens. The development of PTSD results from a cascade of events with contributions from multiple processes and the underlying pathophysiology is complex, involving neurotransmitters, neurocircuitry, and neuroanatomical pathways. Presently, only two medications are US FDA-approved for the treatment of PTSD, both selective serotonin reuptake inhibitors (SSRIs). However, the complex underlying pathophysiology suggests a number of alternative pathways and mechanisms that may be targets for potential drug development. Indeed, investigations and drug development are proceeding in a number of these alternative, non-serotonergic pathways in an effort to improve the management of PTSD. In this manuscript, the authors introduce novel and emerging treatments for PTSD, including drugs in various stages of development and clinical testing (BI 1358894, BNC-210, PRAX-114, JZP-150, LU AG06466, NYV-783, PH-94B, SRX246, TNX-102), established agents and known compounds being investigated for their utility in PTSD (brexpiprazole, cannabidiol, doxasoin, ganaxolone, intranasal neuropeptide Y, intranasal oxytocin, tianeptine oxalate, verucerfont), and emerging psychedelic interventions (ketamine, MDMA-assisted psychotherapy, psilocybin-assisted psychotherapy), with an aim to examine and integrate these agents into the underlying pathophysiological frameworks of trauma-related disorders.

Esketamine-induced post-traumatic stress disorder flashbacks during treatment-resistant depression indication: is it just a side effect?

Background

Posttraumatic stress disorder (PTSD) is a severe and frequent affection that is highly comorbid to major depressive disorder. Comorbid PTSD and depression are usually treatment-resistant, with a high risk of functional impairment and suicide. Esketamine nasal spray is a recent validated treatment for treatment-resistant depression (TRD), but its efficacy on comorbid TRD-PTSD remains insufficiently documented. In particular, flashbacks can occur during esketamine administration and their influence on clinical outcomes is unknown.

Objectives

Our main objective was to describe esketamine-induced traumatic flashbacks and their impact on clinical trajectories within a sample of patients with comorbid TRD-PTSD.

Methods

We retrospectively collected clinical data of patients receiving esketamine nasal spray for TRD with comorbid PTSD who experienced at least one flashback of their trauma during esketamine sessions across 11 psychiatric departments.

Results

Between February 2020 and March 2023, 22 adult patients with TRD met inclusion criteria. In sixteen patients (72.7%) flashbacks disappeared as the sessions progressed. In six patients (27.3%), esketamine treatment was stopped because of persistent flashbacks. When esketamine was continued, clinical response was observed both for depression and PTSD (depression response rate: 45.5% and remission rate: 22.7%; PTSD response rate: 45.5% and remission: 18.2%).

Limitations

The retrospective design of the study and the absence of a comparator group are the main limitations of our study.

Conclusions

Our results suggest that the occurrence of esketamine-induced traumatic flashbacks does not hinder clinical response. On the contrary, when managed appropriately and combined with targeted psychotherapy, it could even contribute to positive outcomes.

A systematic review of the incidence of medical serious adverse events in sub-anesthetic ketamine treatment of psychiatric disorders

BACKGROUND

Limited published data exists that collates serious adverse outcomes involving ketamine as a psychiatric intervention. This systematic review assesses the reported incidence of medical serious adverse events (MSAEs), including but not limited to cardiovascular events, in patients receiving sub-anesthetic doses of ketamine for psychiatric disorders to guide practitioners during treatment planning, risk-benefit analyses, and the informed consent process.

METHODS

Pubmed database was searched for clinical trials of sub-anesthetic ketamine for psychiatric disorders in non-pregnant adult patients. Of the 2275 articles identified, 93 met inclusion criteria, over half of which were published in 2017 or later. Only studies that reported adverse events were included, and the incidence of MSAEs was calculated.

RESULTS

Of the 3756 participants who received at least one sub-anesthetic dose of ketamine, four participants experienced a MSAE, resulting in an incidence of approximately 0.1 % of individuals. The four MSAEs resolved without reported sequelae. Eighty-three percent of studies reported screening for medical illness and exclusion of high-risk patients. There were no serious cardiac adverse events or deaths observed in any participants; however, most trials' study designs excluded those with high cardiovascular complication risk.

LIMITATIONS

Most studies were small, underpowered for detecting rare MSAEs, at potential high-risk of bias of non-report of MSAEs, and limited mostly to intranasal and intravenous routes.

CONCLUSIONS

Findings suggest that with basic medical screening there is a very low incidence of MSAEs including adverse cardiac or cerebrovascular events in individuals receiving sub-anesthetic ketamine for psychiatric disorders.

So how special is special K? A systematic review and meta-analysis of ketamine for PTSD RCTs

Background: PTSD is a significant mental health problem worldwide. Current evidence-based interventions suffer various limitations. Ketamine is a novel agent that is hoped to be incrementally better than extant interventions.Objective: Several randomized control trials (RCTs) of ketamine interventions for PTSD have now been published. We sought to systematically review and meta-analyse results from these trials to evaluate preliminary evidence for ketamine's incremental benefit above-and-beyond control interventions in PTSD treatment.Results: Omnibus findings from 52 effect sizes extracted across six studies (n = 221) yielded a small advantage for ketamine over control conditions at reducing PTSD symptoms (g = 0.27, 95% CI = 0.03, 0.51). However, bias-correction estimates attenuated this effect (adjusted g = 0.20, 95%, CI = -0.08, 0.48). Bias estimates indicated smaller studies reported larger effect sizes favouring ketamine. The only consistent timepoint assessed across RCTs was 24-hours post-initial infusion. Effects at 24-hours post-initial infusion suggest ketamine has a small relative advantage over controls (g = 0.35, 95% CI = 0.06, 0.64). Post-hoc analyses at 24-hours post-initial infusion indicated that ketamine was significantly better than passive controls (g = 0.44, 95% CI = 0.03, 0.85), but not active controls (g = 0.24, 95% CI = -0.30, 0.78). Comparisons one-week into intervention suggested no meaningful group differences (g = 0.24, 95% CI = 0.00, 0.48). No significant differences were evident for RCTs that examined effects two-weeks post initial infusion (g = 0.17, 95% CI = -0.10, 0.44).Conclusions: Altogether, ketamine-for-PTSD RCTs reveal a nominal initial therapeutic advantage relative to controls. However, bias and heterogeneity appear problematic. While rapid acting effects were observed, all control agents (including saline) also evidenced rapid acting effects. We argue blind penetration to be a serious concern, and that placebo is the likely mechanism behind reported therapeutic effects.

Ketamine in neuropsychiatric disorders: an update

The discovery of ketamine as a rapid-acting antidepressant led to a new era in the development of neuropsychiatric therapeutics, one characterized by an antidepressant response that occurred within hours or days rather than weeks or months. Considerable clinical research supports the use of-or further research with-subanesthetic-dose ketamine and its (S)-enantiomer esketamine in multiple neuropsychiatric disorders including depression, bipolar disorder, anxiety spectrum disorders, substance use disorders, and eating disorders, as well as for the management of chronic pain. In addition, ketamine often effectively targets symptom domains associated with multiple disorders, such as anxiety, anhedonia, and suicidal ideation. This manuscript: 1) reviews the literature on the pharmacology and hypothesized mechanisms of subanesthetic-dose ketamine in clinical research; 2) describes similarities and differences in the mechanism of action and antidepressant efficacy between racemic ketamine, its (S) and (R) enantiomers, and its hydroxynorketamine (HNK) metabolite; 3) discusses the day-to-day use of ketamine in the clinical setting; 4) provides an overview of ketamine use in other psychiatric disorders and depression-related comorbidities (e.g., suicidal ideation); and 5) provides insights into the mechanisms of ketamine and therapeutic response gleaned from the study of other novel therapeutics and neuroimaging modalities.

Psychedelic therapies reconsidered: compounds, clinical indications, and cautious optimism

The clinical investigation of psychedelic medicines has blossomed over the last 5 years. Data from a Phase 3 industry trial and a multicenter Phase 2 industry trial, in addition to multiple early phase investigator-initiated and industry trials, have now been published in peer-reviewed journals. This narrative review summarizes both the recent data and the current clinical trials that are being conducted with various classes of "psyche-manifesting" substances, which may prove beneficial in the treatment of a broad range of conditions. Methodological considerations, unique challenges, and next steps for research are discussed in keeping with the uniquely "experiential" nature of these therapies.

Ketamine-Assisted Group Psychotherapy for Frontline Healthcare Workers with COVID-19-Related Burnout and PTSD: A Case Series of Effectiveness/Safety for 10 Participants

This study reports on 10 frontline healthcare workers, employed during the COVID-19 pandemic and experiencing symptoms of burnout and PTSD, treated with group ketamine-assisted psychotherapy (KAP) in a private outpatient clinic setting. Participants attended 6 sessions once weekly. These included 1 preparation session, 3 ketamine sessions (2 sublingual, 1 intramuscular), 2 integration sessions. Measures of PTSD (PCL-5), depression (PHQ-9), and anxiety (GAD-7) were administered at baseline and post-treatment. During ketamine sessions, the Emotional Breakthrough Inventory (EBI) and the 30-item Mystical Experience Questionnaire (MEQ-30) were recorded. Participant feedback was gathered 1-month post-treatment. We observed improvements in participants' average PCL-5 (59% reduction), PHQ-9 (58% reduction), and GAD-7 (36% reduction) scores from pre- to post-treatment. At post-treatment, 100% of participants screened negative for PTSD, 90% had minimal/mild depression or clinically significant improvement, and 60% had minimal/mild anxiety or clinically significant improvement. MEQ and EBI scores had large variations among participants at each ketamine session. Ketamine was well tolerated, and no significant adverse events were reported. Participant feedback corroborated findings of improvements observed in mental health symptoms. We found immediate improvements treating 10 frontline healthcare workers experiencing burnout, PTSD, depression, and anxiety using weekly group KAP and integration.

The effect of obstructive sleep apnea severity on PTSD symptoms during the course of esketamine treatment: a retrospective clinical study

STUDY OBJECTIVES

Intranasal administration of esketamine is Food and Drug Administration-approved for treatment-resistant depression. In a recent retrospective case series, we show that it has promise in reducing symptoms of posttraumatic stress disorder (PTSD) as well. Untreated obstructive sleep apnea (OSA) is prevalent among veterans with PTSD and has been shown to interfere with other PTSD treatments. In the current study, we examined whether OSA impacts esketamine's effectiveness in reducing symptoms of PTSD or depression.

METHODS

Participants were 60 veterans with a diagnosis of major depressive disorder and PTSD who received intranasal esketamine treatment at the San Diego Veterans Affairs (VA) Medical Center. We used growth-curve modeling to examine changes in depression and PTSD symptoms following esketamine treatments and, in the subset of individuals screened for OSA (n = 24, all prescribed positive airway pressure therapy), examined the impacts of OSA severity on these trajectories.

RESULTS

We first showed that both PTSD and depressive symptoms significantly decreased over the course of esketamine treatment. In the subset of veterans screened for OSA, individuals with lower OSA severity reported the greatest reduction in PTSD symptoms, while veterans with the most severe OSA reported the least reduction in PTSD symptoms. Depression response was not affected by severity of OSA in this analysis.

CONCLUSIONS

Veterans with PTSD and depression tend to benefit from esketamine treatment, but OSA may interfere with esketamine effectiveness. Comorbid OSA should be assessed for and treated to maximize esketamine's benefits in PTSD.

CITATION

Titone MK, Hunt C, Bismark A, et al. The effect of obstructive sleep apnea severity on PTSD symptoms during the course of esketamine treatment: a retrospective clinical study. J Clin Sleep Med. 2023;19(12):2043-2051.

Ketamine counteracts sevoflurane-induced depressive-like behavior and synaptic plasticity impairments through the adenosine A2A receptor/ERK pathway in rats

Ketamine is an ionic glutamic acid N-methyl-d-aspartate receptor (NMDAR) antagonist commonly used in clinical anesthesia, and its rapid and lasting antidepressant effect has stimulated great interest in psychology research. However, the molecular mechanisms underlying its antidepressant action are still undetermined. Sevoflurane exposure early in life might induce developmental neurotoxicity and mood disorders. In this study, we evaluated the effect of ketamine against sevoflurane-induced depressive-like behavior and the underlying molecular mechanisms. Here, we reported that A2AR protein expression was upregulated in rats with depression induced by sevoflurane inhalation, which was reversed by ketamine. Pharmacological experiments showed that A2AR agonists could reverse the antidepressant effect of ketamine, decrease extracellular signal-regulated kinase (ERK) phosphorylation, reduce synaptic plasticity, and induce depressive-like behavior. Our results suggest that ketamine mediates ERK1/2 phosphorylation by downregulating A2AR expression and that p-ERK1/2 increases the production of synaptic-associated proteins, enhancing synaptic plasticity in the hippocampus and thereby ameliorating the depressive-like behavior induced by sevoflurane inhalation in rats. This research provides a framework for reducing anesthesia-induced developmental neurotoxicity and developing new antidepressants.

Manipulating critical memory periods to treat psychiatry disorders

The persistence of pathological memory is the basis of several psychiatric disorders. Memory retrieval induces "reconsolidation", a time interval during which the original memory becomes labile and destabilized. Time- and retrieval-dependent processes and memory reconsolidation are critical periods for memory interference. Modulating memory reconsolidation has received considerable research attention as a treatment protocol for several psychiatric conditions such as posttraumatic stress disorder, addiction, anxiety, and trauma-related disorders. This specific time window provides an opportunity for intervention regarding mental diseases. This article reviews the effect of modulating memory reconsolidation using behavioral-, brain stimulation-, and pharmacological-based interventions, which may help bridge the gap between intervention in laboratories and application in clinical practice. The potential advantages, limitations, challenges, and opportunities for memory reconsolidation manipulations were discussed.

Psychedelic-Assisted Therapy in Military and Veterans Healthcare Systems: Clinical, Legal, and Implementation Considerations

PURPOSE OF REVIEW

This review discusses the current and projected landscape of psychedelic-assisted therapy (PAT), with a focus on clinical, legal, and implementation considerations in Department of Defense (DoD) and Department of Veterans Affairs (VA) healthcare systems.

RECENT FINDINGS

3,4-Methylenedioxymethamphetamine (MDMA)- and psilocybin-assisted therapy have shown promising outcomes in efficacy, safety, tolerability, and durability for PTSD and depression, respectively. MDMA-assisted therapy is already approved by the Food and Drug Administration (FDA) on an Expanded Access ("compassionate use") basis for PTSD, with full approval projected for 2024. Psilocybin-assisted therapy is projected to be FDA-approved for depression soon thereafter. Other psychedelics are in earlier stages of development. The VA is currently conducting PAT clinical trials. Although there are clear legal pathways for the VA and DoD to conduct PAT trials, a number of implementation barriers exist, such as the very high number of clinical hours necessary to treat each patient, resource requirements to support treatment infrastructure, military-specific considerations, and the high level of evidence necessary for PAT to be recommended in clinical practice guidelines. Ongoing considerations are whether and how PAT will be made available to VA and DoD beneficiaries, feasibility and cost-effectiveness, and ethical safeguards that must be implemented to prioritize access to PAT given the likelihood of extremely limited initial availability. However, with imminent FDA approval of PATs and considerable national interest in these treatments, DoD and VA policymakers must be prepared with clearly delineated policies and plans for how these healthcare systems will approach PAT.

Psychedelics in the treatment of eating disorders: Rationale and potential mechanisms

Eating disorders are serious illnesses showing high rates of mortality and comorbidity with other mental health problems. Psychedelic-assisted therapy has recently shown potential in the treatment of several common comorbidities of eating disorders, including mood disorders, post-traumatic stress disorder, and substance use disorders. The theorized therapeutic mechanisms of psychedelic-assisted therapy suggest that it could be beneficial in the treatment of eating disorders as well. In this review, we summarize preliminary data on the efficacy of psychedelic-assisted therapy in people with anorexia nervosa, bulimia nervosa, and binge eating disorder, which include studies and case reports of psychedelic-assisted therapy with ketamine, MDMA, psilocybin, and ayahuasca. We then discuss the potential therapeutic mechanisms of psychedelic-assisted therapy in these three eating disorders, including both general therapeutic mechanisms and those which are relatively specific to eating disorders. We find preliminary evidence that psychedelic-assisted therapy may be effective in the treatment of anorexia nervosa and bulimia nervosa, with very little data available on binge eating disorder. Regarding mechanisms, psychedelic-assisted therapy may be able to improve beliefs about body image, normalize reward processing, promote cognitive flexibility, and facilitate trauma processing. Just as importantly, it appears to promote general therapeutic factors relevant to both eating disorders and many of their common comorbidities. Lastly, we discuss potential safety concerns which may be associated with these treatments and present recommendations for future research.

Long term structural and functional neural changes following a single infusion of Ketamine in PTSD

NMDA receptor antagonists have a vital role in extinction, learning, and reconsolidation processes. During the reconsolidation window, memories are activated into a labile state and can be reconsolidated in an altered form. This concept might have significant clinical implications in treating PTSD. In this pilot study we tested the potential of a single infusion of ketamine, followed by brief exposure therapy, to enhance post-retrieval extinction of PTSD trauma memories. 27 individuals diagnosed with PTSD were randomly assigned to receive either ketamine (0.5 mg/kg 40 min; N = 14) or midazolam (0.045 mg/kg; N = 13) after retrieval of the traumatic memory. 24 h following infusion, participants received a four-day trauma-focused psychotherapy. Symptoms and brain activity were assessed before treatment, at the end of treatment, and at 30-day follow-up. Amygdala activation to trauma scripts (a major biomarker of fear response) served as the main study outcome. Although PTSD symptoms improved equally in both groups, post-treatment, ketamine recipients showed a lower amygdala (-0.33, sd = 0.13, 95%HDI [-0.56,-0.04]) and hippocampus (-0.3 (sd = 0.19), 95%HDI [-0.65, 0.04]; marginal effect) reactivation to trauma memories, compared to midazolam recipients. Post-retrieval ketamine administration was also associated with decreased connectivity between the amygdala and hippocampus (-0.28, sd = 0.11, 95%HDI [-0.46, -0.11]), with no change in amygdala-vmPFC connectivity. Moreover, reduction in fractional anisotropy in bi-lateral uncinate fasciculus was seen in the Ketamine recipients compared with the midazolam recipients (right: post-treatment: -0.01108, 95% HDI [-0.0184,-0.003]; follow-up: -0.0183, 95% HDI [-0.02719,-0.0107]; left: post-treatment: -0.019, 95% HDI [-0.028,-0.011]; follow-up: -0.017, 95% HDI [-0.026,-0.007]). Taken together it is possible that ketamine may enhance post-retrieval extinction of the original trauma memories in humans. These preliminary findings show promising direction toward the capacity to rewrite human traumatic memories and modulate the fear response for at least 30 days post-extinction. When combined with psychotherapy for PTSD, further investigation of ketamine dose, timing of administration, and frequency of administration, is warranted.

A transdiagnostic systematic review and meta-analysis of ketamine's anxiolytic effects

BACKGROUND

Ketamine may be effective in treating symptoms of anxiety, but the time profile of ketamine's anxiolytic effect is ill-defined. This systematic review and meta-analysis investigated the anxiolytic effect of ketamine at different time points across a range of clinical settings.

METHODS

Electronic databases were searched to capture randomised control trials measuring the anxiolytic effects of ketamine in contexts including mood disorders, anxiety disorders and chronic pain. Meta-analyses were conducted using a random-effects model. The correlations between (1) improvements in mean anxiety and depression scores, and (2) peak dissociation and improvements in mean anxiety scores were also assessed.

RESULTS

In all, 14 studies met inclusion criteria. Risk of bias was high in 11 studies. Ketamine significantly reduced anxiety scores compared to placebo at acute (<12 h; standard mean difference (SMD): -1.17, 95% confidence interval (CI) [-1.89, -0.44], p < 0.01), subacute (24 h; SMD: -0.44, 95% CI [-0.65, -0.22], p < 0.01) and sustained (7-14 days; SMD: -0.40, 95% CI [-0.63, -0.17], p < 0.01) time points. Exploratory analyses revealed improvements in anxiety and depression symptoms correlated at both subacute (R2 = 0.621, p = 0.035) and sustained time points (R2 = 0.773, p = 0.021). The relationship between peak dissociation and improvement in anxiety was not significant.

CONCLUSIONS

Ketamine appears to offer rapid and sustained anxiety symptom relief across a range of clinical settings, with anxiolytic effects occurring within the first 12 h of administration and remaining effective for 1-2 weeks. Future studies could explore the effects of ketamine maintenance therapy on anxiety symptoms.

Ketamine Use in Child and Adolescent Psychiatry: Emerging Data in Treatment-Resistant Depression, Insights from Adults, and Future Directions

PURPOSE OF REVIEW

The following review will explore ketamine's antidepressant and antisuicidal properties in adults, review of what is known about ketamine's safety in children, and summarize the limited information we have on ketamine's role in treating depression and suicidal ideation in adolescents with depression. Future directions for ketamine's role in child psychiatry based on animal and adult studies will also be explored.

RECENT FINDINGS

Over the past 20 years, ketamine has emerged as a novel treatment for depression and suicidal ideation in adults. In recent years, these studies have been extended to adolescents. In 2021, the first placebo-controlled trial examining ketamine's antidepressant potential in adolescents was performed, demonstrating superior efficacy over midazolam. Initial studies suggest that ketamine functions as a rapidly acting antidepressant in adolescents. Case reports suggest that ketamine may also reduce suicidal ideation in this population. However, existing studies are small, and more research is needed to solidify these findings and inform clinical practice.

Chronic exposure to (2 R,6 R)-hydroxynorketamine induces developmental neurotoxicity in hESC-derived cerebral organoids

(R,S)-ketamine (ketamine) has been increasingly used recreationally and medicinally worldwide; however, it cannot be removed by conventional wastewater treatment plants. Both ketamine and its metabolite norketamine have been frequently detected to a significant degree in effluents, aquatic, and even atmospheric environments, which may pose risks to organisms and humans via drinking water and aerosols. Ketamine has been shown to affect the brain development of unborn babies, while it is still elusive whether (2 R,6 R)-hydroxynorketamine (HNK) induces similar neurotoxicity. Here, we investigated the neurotoxic effect of (2 R,6 R)-HNK exposure at the early stages of gestation by applying human cerebral organoids derived from human embryonic stem cells (hESCs). Short-term (2 R,6 R)-HNK exposure did not significantly affect the development of cerebral organoids, but chronic high-concentration (2 R,6 R)-HNK exposure at day 16 inhibited the expansion of organoids by suppressing the proliferation and augmentation of neural precursor cells (NPCs). Notably, the division mode of apical radial glia was unexpectedly switched from vertical to horizontal division planes following chronic (2 R,6 R)-HNK exposure in cerebral organoids. Chronic (2 R,6 R)-HNK exposure at day 44 mainly inhibited the differentiation but not the proliferation of NPCs. Overall, our findings indicate that (2 R,6 R)-HNK administration leads to the abnormal development of cortical organoids, which may be mediated by inhibiting HDAC2. Future clinical studies are needed to explore the neurotoxic effects of (2 R,6 R)-HNK on the early development of the human brain.

A System for Rapidly Yet Rigorously Evaluating the Quality of Randomized Controlled Trials

ABSTRACT

This tutorial describes a system for rapidly yet rigorously assessing the quality of randomized controlled trials (RCTs). The system has 7 criteria, represented by the acronym "BIS FOES." The BIS FOES system directs readers to assess RCTs based on the following 7 criteria: the RCT's use (or not) of effective (1) Blinding; the RCT's use (or not) of (2) Intent-to-Treat Analysis; the RCT's (3) Size and other information reflecting the effectiveness of randomization; the amount of sample lost during (4) Follow-up; the (5) Outcomes examined by the RCT (specifically, the outcome measures used by the RCT), the (6) Effects reported (ie, the statistical and clinical significance of the RCT's primary, secondary, and safety findings), and any (7) Special Considerations (ie, additional strengths, limitations, or notable features of the RCT). The first 6 criteria are of basic importance to the assessment of every RCT, whereas the Special Considerations criteria allows the system to be expanded to include virtually any other important aspect of the RCT. This tutorial explains the importance of these criteria and how to assess them. This tutorial also describes how many BIS FOES criteria can be initially assessed from the RCT Abstract while also directing readers to specific locations in the RCT article where additional important information can be found. We hope that the BIS FOES system will help healthcare trainees, but also potentially clinicians, researchers, and the general public, rapidly and thoroughly assess RCTs.

Ketamine for Treatment of Posttraumatic Stress Disorder: State of the Field

Posttraumatic stress disorder (PTSD) is a chronic and debilitating condition. Although several psychotherapeutic and pharmacological treatments are recommended for PTSD, many individuals do not respond to treatment or respond only partially, highlighting a critical need for additional treatments. Ketamine has the potential to address this therapeutic need. This review discusses how ketamine emerged as a rapid-acting antidepressant and has become a potential treatment for PTSD. A single dose of intravenous (IV) ketamine has been shown to facilitate rapid reduction of PTSD symptoms. Repeated IV ketamine administration significantly improved PTSD symptoms, compared with midazolam, in a predominantly civilian sample of individuals with PTSD. However, in a veteran and military population, repeated IV ketamine did not significantly reduce PTSD symptoms. Further study of ketamine as a treatment for PTSD is necessary, including which populations benefit most from this therapy and the potential benefits of combining psychotherapy and ketamine.

Phytochemical interventions for post-traumatic stress disorder: A cluster co-occurrence network analysis using CiteSpace

OBJECTIVE

This study investigated trends in the study of phytochemical treatment of post-traumatic stress disorder (PTSD).

METHODS

The Web of Science database (2007-2022) was searched using the search terms "phytochemicals" and "PTSD," and relevant literature was compiled. Network clustering co-occurrence analysis and qualitative narrative review were conducted.

RESULTS

Three hundred and one articles were included in the analysis of published research, which has surged since 2015 with nearly half of all relevant articles coming from North America. The category is dominated by neuroscience and neurology, with two journals, Addictive Behaviors and Drug and Alcohol Dependence, publishing the greatest number of papers on these topics. Most studies focused on psychedelic intervention for PTSD. Three timelines show an "ebb and flow" phenomenon between "substance use/marijuana abuse" and "psychedelic medicine/medicinal cannabis." Other phytochemicals account for a small proportion of the research and focus on topics like neurosteroid turnover, serotonin levels, and brain-derived neurotrophic factor expression.

CONCLUSION

Research on phytochemicals and PTSD is unevenly distributed across countries/regions, disciplines, and journals. Since 2015, the research paradigm shifted to constitute the mainstream of psychedelic research thus far, leading to the exploration of botanical active ingredients and molecular mechanisms. Other studies focus on anti-oxidative stress and anti-inflammation. Please cite this article as: Gao B, Qu YC, Cai MY, Zhang YY, Lu HT, Li HX, Tang YX, Shen H. Phytochemical interventions for post-traumatic stress disorder: A cluster co-occurrence network analysis using CiteSpace. J Integr Med. 2023; Epub ahead of print.

Case report: Improvement in refractory functional seizures, depression, and quality of life with ketamine-assisted therapy

Functional seizures, a primary subtype of functional neurological disorder (FND), are a known cause of serious neurological disability with an increasing awareness of their impact amongst the neuroscience community. Situated at the intersection of neurology and psychiatry, FND is characterized by a range of alterations in motor, sensory or cognitive performance, such as abnormal movements, limb weakness, and dissociative, seizure-like episodes. Functional seizures are known, in part, to have psychological underpinnings; however, the lack of effective and consistent treatment options requires research and novel approaches to better understand the etiology, diagnosis and what constitutes a successful intervention. Ketamine, a selective blocker of the N-methyl-D-aspartate receptor, has a well-established safety and efficacy profile. In recent years, ketamine-assisted therapy has shown increasing potential for treating a broad range of psychiatric conditions, building on its demonstrated rapid-acting antidepressant effects. Here we present a 51-year-old female with refractory daily functional seizures leading to significant disability and a medical history significant for major depressive disorder (MDD) and posttraumatic stress disorder (PTSD). After unsuccessful treatment attempts, the patient underwent a novel protocol with ketamine-assisted therapy. After 3 weeks of ketamine-assisted therapy followed by 20 weeks of intermittent ketamine treatment and ongoing integrative psychotherapy, the patient's seizures were significantly reduced in frequency and severity. She experienced significant improvements in depressive symptoms and functional ability scores. To our knowledge, this is the first reported case describing improvement in functional seizures following ketamine-assisted therapy. While rigorous studies are needed, this case report encourages further investigation of ketamine-assisted therapy for functional seizures and other functional neurological symptoms.

A pilot randomized controlled trial of ketamine in Borderline Personality Disorder

This study is the first randomized controlled trial to test the effects of ketamine in Borderline Personality Disorder (BPD). BPD remains undertreated in the community and no medication has FDA approval for this indication. People with BPD experience chronic mood disturbances with depressed mood, suicidal ideation, and severe social difficulties. In this double-blind, randomized controlled pilot study, we tested the effects of one infusion of ketamine (0.5 mg/kg, n = 10) or the psychoactive comparator drug midazolam (0.04 mg/kg, n = 12) in adults with BPD. Infusions were well tolerated in both groups. Dissociative symptoms during infusion were more intense with ketamine than midazolam (t(12.3) = 3.61, p = 0.01), but they resolved by 40 min after infusion in both groups. Post-infusion adverse events were at the expected low levels in both groups. For our primary outcome measure of suicidal ideation and our secondary outcome measure of depression, we found numerical reduction but not significant group or group x timepoint difference (p > 0.05). For our secondary outcome measures of anxiety and BPD symptoms, we did not observe group or group x timepoint differences. There was a group x timepoint effect for socio-occupational functioning (F(1,20.12) = 5.16, p = 0.03, at Day 14, ketamine group showed more improvement than midazolam group). An exploratory analysis revealed that improvement in socio-occupational functioning was correlated with improvement in depression in the ketamine group (r(8) = 0.65, p = 0.04) but not midazolam group (r(9) = 0.41, p = 0.216). This pilot study provides the first randomized controlled evidence of the effects of antidepressant-dosed ketamine in people with BPD. Our results provide reason for optimism that antidepressant-dosed ketamine will be well-tolerated in larger studies and may provide clinical benefit for mood symptoms and related impairments in people with BPD.

The antidepressant actions of ketamine and its enantiomers

Ketamine, an N-methyl-d-aspartate receptor (NMDAR) antagonist first developed as an anesthetic, has shown significant promise as a medication with rapid antidepressant properties in treatment-resistant depression. However, concerns such as adverse side effects and potential misuse liability have limited its widespread use. Racemic ketamine has two enantiomers-(S)- and (R)-ketamine-that appear to have disparate underlying mechanisms. This brief review summarizes some of the most recent preclinical and clinical research regarding the convergent and divergent prophylactic, immediate, and sustained antidepressant effects of (S)- and (R)-ketamine while addressing potential differences in their side effect and misuse liability profiles. Preclinical research suggests divergent mechanisms underlying (S)- and (R)-ketamine, with (S)-ketamine more directly affecting mechanistic target of rapamycin complex 1 (mTORC1) signaling and (R)-ketamine more directly affecting extracellular signal-related kinase (ERK) signaling. Clinical research suggests that (R)-ketamine has a milder side effect profile than (S)-ketamine and decreases depression rating scale scores, but recent randomized, controlled trials found that it had no significant antidepressant efficacy compared to placebo, suggesting that caution is warranted in interpreting its therapeutic potential. Future preclinical and clinical research is needed to maximize the efficacy of each enantiomer, either by optimizing dose, route of administration, or administration paradigm.

Ketamine and psychotherapy for the treatment of psychiatric disorders: systematic review

BACKGROUND

Ketamine is an effective short-term treatment for a range of psychiatric disorders. A key question is whether the addition of psychotherapy to ketamine treatment improves outcomes or delays relapse.

AIM

To identify all studies combining psychotherapy with ketamine for the treatment of psychiatric disorders to summarise their effects and make recommendations for future research.

METHOD

The review protocol was prospectively registered with PROSPERO (registration number CRD42022318120). Potential studies were searched for in MEDLINE, Embase, PsycINFO, SCOPUS, the Cochrane library and Google Scholar. Eligible studies combined ketamine and psychotherapy for the treatment of psychiatric disorders and did not use case reports or qualitative designs. Key findings relating to psychotherapy type, diagnosis, ketamine protocol, sequencing of psychotherapy and study design are reported. Risk of bias was assessed using modified Joanna Briggs critical appraisal tools.

RESULTS

Nineteen studies evaluating 1006 patients were included in the systematic review. A variety of supportive individual and group, manualised and non-manualised psychotherapies were used. The majority of studies evaluated substance use disorders, post-traumatic stress disorder and treatment-resistant depression. Ketamine protocols and sequencing of ketamine/psychotherapy treatment varied substantially between studies. Outcomes were largely positive for the addition of psychotherapy to ketamine treatment.

CONCLUSION

The combination of psychotherapy and ketamine offers promise for the treatment of psychiatric disorders, but study heterogeneity prevents definitive recommendations for their integration. Larger randomised controlled trials using manualised psychotherapies and standardised ketamine protocols are recommended to clarify the extent to which the addition of psychotherapy to ketamine improves outcomes over ketamine treatment alone.

A pharmacological challenge paradigm to assess neural signatures of script-elicited acute dissociation in women with post-traumatic stress disorder

BACKGROUND

There is limited experimentally controlled neuroimaging research available that could explain how dissociative states occur and which neurobiological changes are involved in acute post-traumatic dissociation.

AIMS

To test the causal hypothesis that acute dissociation is triggered bottom-up by a selective noradrenergic-mediated increase in amygdala activation during the processing of autobiographical trauma memories.

METHOD

Women with post-traumatic stress disorder (n = 47) and a history of interpersonal childhood trauma underwent a within-participant, placebo-controlled pharmacological challenge paradigm (4.0 mg reboxetine versus placebo) employing script-driven imagery (traumatic versus neutral autobiographical memory recall). Script-elicited brain activation patterns (measured via functional magnetic resonance imagery) were analysed by means of whole-brain analyses and a pre-registered region of interest (i.e. amygdala).

RESULTS

Self-reported acute dissociation increased significantly during trauma (versus neutral) recall but did not differ between pharmacological conditions. The pharmacological manipulation was also unsuccessful in eliciting increased amygdala activation following script-driven imagery in the reboxetine (versus placebo) condition. In the reboxetine condition, trauma retrieval resulted in similar activation patterns as in the placebo condition (e.g. elevated brain activation in the middle occipital gyrus and supramarginal gyrus), albeit with different peaks.

CONCLUSIONS

Current (null) findings cast doubt on the suggested role of the amygdala in subserving dissociative processing of trauma memories. Alternative pharmacological manipulation approaches (e.g. ketamine) and analysis techniques (e.g. event-related independent component analysis) might provide better insight into the spatiotemporal dynamics and network shifts involved in dissociative experiences and autobiographical trauma memory recall.

The Missing Piece? A Case for Microglia's Prominent Role in the Therapeutic Action of Anesthetics, Ketamine, and Psychedelics

There is much excitement surrounding recent research of promising, mechanistically novel psychotherapeutics - psychedelic, anesthetic, and dissociative agents - as they have demonstrated surprising efficacy in treating central nervous system (CNS) disorders, such as mood disorders and addiction. However, the mechanisms by which these drugs provide such profound psychological benefits are still to be fully elucidated. Microglia, the CNS's resident innate immune cells, are emerging as a cellular target for psychiatric disorders because of their critical role in regulating neuroplasticity and the inflammatory environment of the brain. The following paper is a review of recent literature surrounding these neuropharmacological therapies and their demonstrated or hypothesized interactions with microglia. Through investigating the mechanism of action of psychedelics, such as psilocybin and lysergic acid diethylamide, ketamine, and propofol, we demonstrate a largely under-investigated role for microglia in much of the emerging research surrounding these pharmacological agents. Among others, we detail sigma-1 receptors, serotonergic and γ-aminobutyric acid signalling, and tryptophan metabolism as pathways through which these agents modulate microglial phagocytic activity and inflammatory mediator release, inducing their therapeutic effects. The current review includes a discussion on future directions in the field of microglial pharmacology and covers bidirectional implications of microglia and these novel pharmacological agents in aging and age-related disease, glial cell heterogeneity, and state-of-the-art methodologies in microglial research.

Alleviating anxiety and taming trauma: Novel pharmacotherapeutics for anxiety disorders and posttraumatic stress disorder

Psychiatric disorders associated with psychological trauma, stress and anxiety are a highly prevalent and increasing cause of morbidity worldwide. Current therapeutic approaches, including medication, are effective in alleviating symptoms of anxiety disorders and posttraumatic stress disorder (PTSD), at least in some individuals, but have unwanted side-effects and do not resolve underlying pathophysiology. After a period of stagnation, there is renewed enthusiasm from public, academic and commercial parties in designing and developing drug treatments for these disorders. Here, we aim to provide a snapshot of the current state of this field that is written for neuropharmacologists, but also practicing clinicians and the interested lay-reader. After introducing currently available drug treatments, we summarize recent/ongoing clinical assessment of novel medicines for anxiety and PTSD, grouped according to primary neurochemical targets and their potential to produce acute and/or enduring therapeutic effects. The evaluation of putative treatments targeting monoamine (including psychedelics), GABA, glutamate, cannabinoid, cholinergic and neuropeptide systems, amongst others, are discussed. We emphasize the importance of designing and clinically assessing new medications based on a firm understanding of the underlying neurobiology stemming from the rapid advances being made in neuroscience. This includes harnessing neuroplasticity to bring about lasting beneficial changes in the brain rather than - as many current medications do - produce a transient attenuation of symptoms, as exemplified by combining psychotropic/cognitive enhancing drugs with psychotherapeutic approaches. We conclude by noting some of the other emerging trends in this promising new phase of drug development.

To Predict, Prevent, and Manage Post-Traumatic Stress Disorder (PTSD): A Review of Pathophysiology, Treatment, and Biomarkers

Post-traumatic stress disorder (PTSD) can become a chronic and severely disabling condition resulting in a reduced quality of life and increased economic burden. The disorder is directly related to exposure to a traumatic event, e.g., a real or threatened injury, death, or sexual assault. Extensive research has been done on the neurobiological alterations underlying the disorder and its related phenotypes, revealing brain circuit disruption, neurotransmitter dysregulation, and hypothalamic–pituitary–adrenal (HPA) axis dysfunction. Psychotherapy remains the first-line treatment option for PTSD given its good efficacy, although pharmacotherapy can also be used as a stand-alone or in combination with psychotherapy. In order to reduce the prevalence and burden of the disorder, multilevel models of prevention have been developed to detect the disorder as early as possible and to reduce morbidity in those with established diseases. Despite the clinical grounds of diagnosis, attention is increasing to the discovery of reliable biomarkers that can predict susceptibility, aid diagnosis, or monitor treatment. Several potential biomarkers have been linked with pathophysiological changes related to PTSD, encouraging further research to identify actionable targets. This review highlights the current literature regarding the pathophysiology, disease development models, treatment modalities, and preventive models from a public health perspective, and discusses the current state of biomarker research.