Non-parenteral Ketamine for Depression: A Practical Discussion on Addiction Potential and Recommendations for Judicious Prescribing

IN Esketamine and IV Ketamine: Results of a multi-site observational study assessing the effectiveness and tolerability of two novel therapies for treatment-resistant depression

Intravenous (IV) ketamine and intranasal (IN) esketamine are novel therapies to manage treatment resistant depression within major depressive disorder (MDD-TRD). This is a multi-site observational study aiming to assess the real-world effectiveness and tolerability of these novel therapies in the management of MDD-TRD. 53 patients were referred to receive IV ketamine (n = 26, 69.23 % female, 52.81 ± 14.33 years old) or IN esketamine (n = 27, 51.85 % female, 43.93 ± 13.57 years old). Treatment effectiveness was assessed using the Montgomery and Åsberg Depression Rating Scale (MADRS) for depression severity and item 10 of the MADRS for suicidal ideation (SI). Tolerability was assessed by systematically tracking side effects and depersonalization using the 6-item Clinician administered dissociative symptom scale (CADSS-6). The data was analyzed using descriptive statistics, risk ratio and effect size. Both IV ketamine and IN esketamine significantly reduced depressive symptoms and suicidal ideation by treatment endpoint. Patients receiving IN esketamine, and patients receiving IV ketamine had a similar risk of developing side effects. All side effects reported were mild and transient. These results suggested that both IV ketamine and IN esketamine are effective in the management of depressive symptoms and were well tolerated. Therefore, the results of this study could serve to inform clinical practice.

At-home, telehealth-supported ketamine treatment for depression: Findings from longitudinal, machine learning and symptom network analysis of real-world data

BACKGROUND

Improving safe and effective access to ketamine therapy is of high priority given the growing burden of mental illness. Telehealth-supported administration of sublingual ketamine is being explored toward this goal.

METHODS

In this longitudinal study, moderately-to-severely depressed patients received four doses of ketamine at home over four weeks within a supportive digital health context. Treatment was structured to resemble methods of therapeutic psychedelic trials. Patients receiving a second course of treatment were also examined. Symptoms were assessed using the Patient Health Questionnaire (PHQ-9) for depression. We conducted preregistered machine learning and symptom network analyses to investigate outcomes (osf.io/v2rpx).

RESULTS

A sample of 11,441 patients was analyzed, demonstrating a modal antidepressant response from both non-severe (n = 6384, 55.8 %) and severe (n = 2070, 18.1 %) baseline depression levels. Adverse events were detected in 3.0-4.8 % of participants and predominantly neurologic or psychiatric in nature. A second course of treatment helped extend improvements in patients who responded favorably to initial treatment. Improvement was most strongly predicted by lower depression scores and age at baseline. Symptoms of Depressed mood and Anhedonia sustained depression despite ongoing treatment.

LIMITATIONS

This study was limited by the absence of comparison or control groups and lack of a fixed-dose procedure for ketamine administration.

CONCLUSIONS

At-home, telehealth-supported ketamine administration was largely safe, well-tolerated, and associated with improvement in patients with depression. Strategies for combining psychedelic-oriented therapies with rigorous telehealth models, as explored here, may uniquely address barriers to mental health treatment.

[Psychedelic and dissociative agents in psychiatry: challenges in the treatment]

With the discovery of the antidepressive effects of ketamine and the increasing withdrawal of the pharmaceutical industry from the development of new psychotropic drugs, the psychiatric research into the clinical application of hallucinogens in psychiatry has literally blossomed in the last two decades. Promising results for various treatment approaches with psychedelic agents, such lysergic acid diethylamide (LSD) and psilocybin, and dissociative agents, such as ketamine and esketamine, have raised great hopes among researchers, clinicians and patients in recent years, so that there was already talk of a new era in psychiatry. As one of the first of these substances, in December 2019 intranasal esketamine was approved in the USA and the EU for the treatment of treatment-resistant depression and Switzerland followed in 2020. Recently, psilocybin was approved in Australia, Canada and Switzerland for compassionate use in exceptional cases for the treatment of depression, while large approval studies with various psychedelic agents are currently ongoing worldwide. The medical application of psychedelic agents and ketamine/esketamine is considered to be safe; however, as with all new forms of treatment it is of crucial importance that, in addition to the hopes, the specific challenges of these new treatment approaches must also be carefully considered and assessed. Excessive expectations and an insufficient risk-benefit estimation are detrimental to the patients and the reputation of the treating physician. Although a possible paradigm shift in the care of mental health is already being discussed, this review article consciously concentrates on the possible risks of treatment and the methodological weaknesses of the studies carried out so far.

Beyond therapeutic potential: a systematic investigation of ketamine misuse in patients with depressive disorders

Ketamine, a pharmacological agent that acts as an antagonist of the N-methyl-D-aspartate (NMDA) receptor, has garnered considerable interest because of its notable and expeditious antidepressant properties observed in individuals diagnosed with major depressive disorder (MDD) who exhibit resistance to conventional therapeutic interventions. A comprehensive and rigorous systematic review was undertaken to evaluate the prevalence of ketamine abuse undergoing ketamine treatment for depressive disorders. A comprehensive search was conducted across the electronic databases to identify pertinent studies published between 2021 and 2023. The present investigation incorporated a comprehensive range of studies encompassing the abuse or misuse of ketamine, including case reports, observational studies, and clinical trials. Data extraction and quality assessment were conducted in accordance with predetermined criteria. The findings of this systematic review demonstrate the importance of monitoring and addressing ketamine abuse in patients receiving ketamine treatment for depressive disorders like MDD. The wide range of reported prevalence rates highlights the need for standardized criteria and measures for defining and assessing ketamine abuse. This study presents a significant contribution to the field by introducing a novel screening questionnaire and assessment algorithm designed to identify and evaluate ketamine misuse among major depressive disorder (MDD) patients undergoing ketamine treatment. This innovative tool holds the potential to enhance clinical practice by providing healthcare professionals with a standardized approach to promptly detect and address ketamine misuse. The integration of this screening tool into routine care protocols can facilitate more effective monitoring and management of ketamine misuse in this population, ultimately leading to improved patient outcomes and safety.

Guidelines for ketamine use in clinical psychiatry practice

In this editorial, we emphasise the efficacy and challenges of using ketamine in treatment-resistant depression. We highlight the need for comprehensive evidence-based guidelines to manage the use of both licensed and off-licence ketamine formulations and discuss recent efforts by Beaglehole et al to develop ketamine guidelines in New Zealand. We finally advocate for national registries to monitor ketamine therapy, ensuring its responsible and effective use in the management of depression.

Protocol for a randomised controlled trial of ketamine versus ketamine and behavioural activation therapy for adults with treatment-resistant depression in the community

INTRODUCTION

Although short-term benefits follow parenteral ketamine for treatment-resistant major depressive disorder (TR-MDD), there are challenges that prevent routine use of ketamine by clinicians. These include acute dissociative effects of parenteral ketamine, high relapse rates following ketamine dosing and the uncertain role of psychotherapy. This randomised controlled trial (RCT) seeks to establish the feasibility of evaluating repeated oral doses of ketamine and behavioural activation therapy (BAT), compared with ketamine treatment alone, for TR-MDD. We also aim to compare relapse rates between treatment arms to determine the effect size of adding BAT to oral ketamine.

METHODS AND ANALYSIS

This is a prospectively registered, two-centre, single-blind RCT. We aim to recruit 60 participants with TR-MDD aged between 18 and 65 years. Participants will be randomised to 8 weeks of oral ketamine and BAT, or 8 weeks of oral ketamine alone. Feasibility will be assessed by tracking attendance for ketamine and BAT, acceptability of treatment measures and retention to the study follow-up protocol. The primary efficacy outcome measure is the Montgomery-Asberg Depression Rating Scale (MADRS) measured weekly during treatment and fortnightly during 12 weeks of follow-up. Other outcome measures will assess the tolerability of ketamine and BAT, cognition and activity (using actigraphy). Participants will be categorised as non-responders, responders, remitters and relapsed during follow-up. MADRS scores will be analysed using a linear mixed model. For a definitive follow-up RCT study to be recommended, the recruitment expectations will be met and efficacy outcomes consistent with a >20% reduction in relapse rates favouring the BAT and ketamine arm will be achieved.

ETHICS AND DISSEMINATION

Ethics approval was granted by the New Zealand Central Health and Disability Ethics Committee (reference: 2023 FULL18176). Study findings will be reported to participants, stakeholder groups, conferences and peer-reviewed publications.

TRIAL REGISTRATION NUMBER

UTN: U1111-1294-9310, ACTRN12623000817640p.

IV low dose ketamine infusions for treatment resistant depression: Results from a five-year study at a free public clinic in an academic hospital

Individuals with major depressive disorder and treatment resistant depression (MDD-TRD) have limited and sometimes poorly tolerated therapeutic options. Low dose ketamine has presented promising and potent antidepressant effects in this population. To support the existent literature, we conducted a longitudinal study examining five years of real-world clinical data on the use of IV low-dose ketamine alongside standard care for MDD-TRD outpatients. For this study we collected demographic information, clinical scale scores, side effects and dropout data. The data was analyzed using descriptive statistics, effect size using Cohen's D analysis, and multivariate ANOVA (MANOVA) to determine the impact of sociodemographic variables. 71 outpatients (50.28 years old, SD: 14.26; female 74.65%) were included in the analysis. The results showed a significant reduction in depressive symptoms and suicide ideation (SI) by treatment endpoint. 54.93% of patients responded to the treatment, 78.26% experienced transient and mild side effects, and 11.27% of dropped out of the treatment. Multivariate analysis showed that the demographic variables did not impact treatment effect or tolerability. The results of this study suggest that IV low dose ketamine treatment is effective, fast-acting, and well tolerated for the management of depressive symptoms and SI in patients with MDD-TRD in naturalistic clinical practice.

Drug dependence and prescribing ketamine for treatment-resistant depression in Australia and New Zealand

Ketamine is a restricted and regulated medication in Australia and New Zealand, which has implications when considering treatment for patients with treatment-resistant depression and a history of illicit drug use, abuse or dependence. Regulations governing prescription of ketamine for treatment-resistant depression vary between jurisdictions in Australia and New Zealand, though most restrict use in those with drug dependence. There is substantial variation in definitions of drug dependence used in each jurisdiction, and between the legal and clinical definitions, with the latter specified in the current International Classification of Diseases, Eleventh Revision and Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. This paper reviews the literature assessing the risk of ketamine misuse and dependence in patients with a history of illicit drug use, abuse or dependence and presents recommendations for psychiatrists who prescribe ketamine in such patients with treatment-resistant depression.

Use of ketamine for treatment resistant depression: updated review of literature and practical applications to a community ketamine program in Edmonton, Alberta, Canada

Background

Though intravenous (IV) ketamine and intranasal (IN) esketamine are noted to be efficacious for treatment-resistant depression (TRD), access to each of these treatments within healthcare systems is limited due to cost, availability, and/or monitoring requirements. IV ketamine has been offered at two public hospital sites in Edmonton, Canada since 2015. Since then, demand for maintenance ketamine treatments has grown. This has required creative solutions for safe, accessible, evidence-based patient care.

Objectives

Aims of this paper are twofold. First, we will provide a synthesis of current knowledge with regards to the clinical use of ketamine for TRD. Consideration will be given regarding; off-label racemic ketamine uses versus FDA-approved intranasal esketamine, populations treated, inclusion/exclusion criteria, dosing, assessing clinical response, concomitant medications, and tolerability/safety. Second, this paper will describe our experience as a community case study in applying evidence-based treatment. We will describe application of the literature review to our clinical programming, and in particular focus on cost-effective maintenance treatments, long-term safety concerns, routes of ketamine administration other than via intravenous, and cautious prescribing of ketamine outside of clinically monitored settings.

Methodology

We conducted a literature review of the on the use of ketamine for TRD up to June 30, 2023. Key findings are reviewed, and we describe their application to our ketamine program.

Conclusion

Evidence for the use of ketamine in resistant depression has grown in recent years, with evolving data to support and direct its clinical use. There is an increasing body of evidence to guide judicious use of ketamine in various clinical circumstances, for a population of patients with a high burden of suffering and morbidity. While large-scale, randomized controlled trials, comparative studies, and longer-term treatment outcomes is lacking, this community case study illustrates that currently available evidence can be applied to real-world clinical settings with complex patients. As cost is often a significant barrier to accessing initial and/or maintenance IV or esketamine treatments, public ketamine programs may incorporate SL or IN ketamine to support a sustainable and accessible treatment model. Three of such models are described.

Oral ketamine may offer a solution to the ketamine conundrum

Ketamine has received considerable attention for its rapid and robust antidepressant response over the past decade. Current evidence, in clinical populations, predominantly relates to parenterally administered ketamine, which is reported to produce significant undesirable side effects, with additional concerns regarding long-term safety and abuse potential. Attempts to produce a similar drug to ketamine, without the psychotomimetic side effects, have proved elusive. Orally administered ketamine has a different pharmacological profile to parentally administered ketamine, suggesting it may be a viable alternative. Emerging evidence regarding the efficacy and tolerability of oral ketamine suggests that it may be a favourable route of administration, as it appears to obtain similarly beneficial treatment effects, but without the cost and medical resources required in parenteral dosing. The pharmacological effects may be due to the active metabolite norketamine, which has been found to be at substantially higher levels via oral dosing, most likely due to first-pass clearance. Despite bioavailability and peak plasma concentrations both being lower than when administered parenterally, evidence suggests that low-dose oral ketamine is clinically effective in treating pain. This may also be due to the actions of norketamine and therefore, its relevance to the mental health context is explored in this narrative review.

Multidisciplinary development of guidelines for ketamine treatment for treatment-resistant major depression disorder for use by adult specialist mental health services in New Zealand

BACKGROUND

The evidence base for racemic ketamine treatment for treatment-resistant major depressive disorder (TRD) continues to expand, but there are major challenges translating this evidence base into routine clinical care.

AIM

To prepare guidelines for ketamine treatment of TRD that are suitable for routine use by publicly funded specialist mental health services.

METHOD

We consulted with senior leadership, clinical pharmacy, psychiatrists, nursing, service users and Māori mental health workers on issues relating to ketamine treatment. We prepared treatment guidelines taking the evidence base for ketamine treatment and the consultation into account.

RESULTS

Ketamine treatment guidance is reported. This offers two treatment pathways, including a test of ketamine responsiveness with intramuscular ketamine and the dominant use of oral ketamine for a 3-month course to maximise the opportunity for the short-term benefits of ketamine to accumulate.

CONCLUSIONS

We have responded to the challenges of translating the evidence base for ketamine treatment into a form suitable for routine care.

Roles of microglia in adult hippocampal neurogenesis in depression and their therapeutics

Adult hippocampal neurogenesis generates functional neurons from neural progenitor cells in the hippocampal dentate gyrus (DG) to complement and repair neurons and neural circuits, thus benefiting the treatment of depression. Increasing evidence has shown that aberrant microglial activity can disrupt the appropriate formation and development of functional properties of neurogenesis, which will play a crucial role in the occurrence and development of depression. However, the mechanisms of the crosstalk between microglia and adult hippocampal neurogenesis in depression are not yet fully understood. Therefore, in this review, we first introduce recent discoveries regarding the roles of microglia and adult hippocampal neurogenesis in the etiology of depression. Then, we systematically discuss the possible mechanisms of how microglia regulate adult hippocampal neurogenesis in depression according to recent studies, which involve toll-like receptors, microglial polarization, fractalkine-C-X3-C motif chemokine receptor 1, hypothalamic-pituitary-adrenal axis, cytokines, brain-derived neurotrophic factor, and the microbiota-gut-brain axis, etc. In addition, we summarize the promising drugs that could improve the adult hippocampal neurogenesis by regulating the microglia. These findings will help us understand the complicated pathological mechanisms of depression and shed light on the development of new treatment strategies for this disease.

Ketamine and Zinc: Treatment of Anorexia Nervosa Via Dual NMDA Receptor Modulation

Anorexia nervosa is a disorder associated with serious adverse health outcomes, for which there is currently considerable treatment ineffectiveness. Characterised by restrictive eating behaviours, distorted body image perceptions and excessive physical activity, there is growing recognition anorexia nervosa is associated with underlying dysfunction in excitatory and inhibitory neurometabolite metabolism and signalling. This narrative review critically explores the role of N-methyl-D-aspartate receptor-mediated excitatory and inhibitory neurometabolite dysfunction in anorexia nervosa and its associated biomarkers. The existing magnetic resonance spectroscopy literature in anorexia nervosa is reviewed and we outline the brain region-specific neurometabolite changes that have been reported and their connection to anorexia nervosa psychopathology. Considering the proposed role of dysfunctional neurotransmission in anorexia nervosa, the potential utility of zinc supplementation and sub-anaesthetic doses of ketamine in normalising this is discussed with reference to previous research in anorexia nervosa and other neuropsychiatric conditions. The rationale for future research to investigate the combined use of low-dose ketamine and zinc supplementation to potentially extend the therapeutic benefits in anorexia nervosa is subsequently explored and promising biological markers for assessing and potentially predicting treatment response are outlined.

The abuse liability of ketamine: A scoping review of preclinical and clinical studies

While ketamine has been used clinically over the past decades, it has only been recently shown to be a promising therapy for treatment-resistant depression (TRD). However, ketamine and related dissociative agents may also be misused recreationally, creating significant concerns for abuse liability when prescribed for depression. Although the abuse potential of ketamine is widely recognized, there is limited evidence on the differential abuse liability of ketamine enantiomers, (S)-ketamine and (R)-ketamine. The current scoping review aims to summarize the extant literature on the abuse liability of (R,S)-ketamine and the enantiomers. A systematic search was conducted on the Embase, Medline, and APA PsycInfo databases from 1947 to July 29, 2021. Clinical and preclinical studies that assessed the abuse potential of (R,S)-ketamine, (S)-ketamine, and (R)-ketamine were screened and assessed for eligibility by two independent reviewers. A total of 65 eligible studies were identified; 55 were preclinical studies and 10 were clinical studies. Only 4 preclinical studies evaluated the abuse liability of ketamine enantiomers. Available preclinical evidence suggests that (R,S)-ketamine and (S)-ketamine have greater risk for abuse compared to (R)-ketamine. (R)-ketamine, at the antidepressant-relevant doses in rodents, appears to be safe with minimal liability for abuse. Although the abuse potential of (R,S)-ketamine is well-established in animals, limited clinical studies indicate that single or repeated ketamine administrations in professionally controlled settings did not result in misuse, dependence, diversion and/or gateway activity in patients with TRD. However, most clinical studies were retrospective and did not systematically evaluate the abuse liability of ketamine via validated psychological scales/questionnaires. Future randomized controlled trials are warranted to ascertain the abuse liability of racemic, (S)- and (R)-ketamine in TRD population, especially among patients with comorbid substance use disorders.

A survey of drug liking and cravings in patients using sublingual or intranasal ketamine for treatment resistant depression: A preliminary evaluation of real world addictive potential

Ketamine has gained rapid popularity as a treatment option for treatment resistant depression (TRD). Though seen only in limited contexts, ketamine is a potential drug of abuse, addiction and diversion. Clinical ketamine studies to date have not systematically evaluated factors relevant to addiction risk in patients with TRD, but in treating patients with ketamine, risks of potential harms related to addiction must be considered. As clinical access to intravenous ketamine programs is limited in much of Canada, these considerations become even more important for clinicians who elect to offer patients less supervised, non-parenteral forms of ketamine treatment. This study explores factors relevant to addiction risk in a real-world sample of 33 patients with TRD currently or previously treated with sublingual (SL) or intranasal (IN) ketamine in the community. First, patients were surveyed using a Drug Liking and Craving Questionnaire (DLCQ) to assess their level of drug liking and craving for ketamine, and to screen for symptoms of a ketamine use disorder. Second, the pharmacy records of these patients were reviewed for red flags for addiction such as dose escalation or early refills. Third, surveys were administered to the treating psychiatrists of patients who had discontinued ketamine to determine if abuse concerns contributed to reason for discontinuation. Though limited to a small sample, results indicate that ketamine is not a universally liked or craved substance in patients with TRD. Prescribers of non-parenteral ketamine should monitor patients and prescribe cautiously. Factors related to addiction (as in the DLCQ) should be explored for clinicians to consider individual risk/benefit for judicious use of ketamine in patients with TRD.