The Canadian Network for Mood and Anxiety Treatments (CANMAT) Task Force Recommendations for the Use of Racemic Ketamine in Adults with Major Depressive Disorder: Recommandations Du Groupe De Travail Du Réseau Canadien Pour Les Traitements De L'humeur Et De L'anxiété (Canmat) Concernant L'utilisation De La Kétamine Racémique Chez Les Adultes Souffrant De Trouble Dépressif Majeur

Repeated subcutaneous esketamine on treatment-resistant depression: An open-label dose titration study

BACKGROUND

Ketamine has gained prominence as one of the most effective therapeutic options in unipolar treatment-resistant depression (TRD). However, most studies related to the antidepressant action of ketamine used intravenous (IV) or intranasal (IN) administration. The subcutaneous (SC) route of administration is a promising alternative, as it results in plasma levels comparable to IV, causes fewer side effects, and is easier and cheaper to administer than both IV and/or IN routes.

METHODS

In this context, we conducted an open-label clinical trial for investigating the efficacy and safety of 8 weekly sessions of SC esketamine in TRD patients (n = 30).

RESULTS

At the end of the treatment, a partial response rate of 26.09 %, a response rate of 52.17 % and remission rate of 34.78 % were observed, assessed by Montgomery-Åsberg Depression Rating Scale. Moreover, the self-reported depressive symptoms, as measured by the Beck Depression Inventory II (BDI-II), significantly decreased from the baseline to the final session, and the improvements were sustained throughout the week. Follow-up evaluations (BDI-II) up to the sixth month consistently showed scores lower than the baseline.

LIMITATIONS

The small sample size and the drop-out during the follow-up phase may limit the generalizability of the findings. Additionally, the absence of a control group necessitates cautious interpretation of causality.

CONCLUSIONS

This groundbreaking study, which addresses SC esketamine treatment for TRD, reported promising response and remission rates, as well as sustained antidepressant effects. It highlights the need for further research to improve and expand our knowledge of this innovative, more accessible, and cost-effective therapeutic approach.

Trends and characteristics in ketamine use among US adults with and without depression, 2015-2022

BACKGROUND

Ketamine's potential for treating depression has drawn increased clinical interest in recent years. However, despite growing therapeutic use, recreational use among individuals with depression remain underexplored.

METHODS

We analyzed data from the 2015-2022 National Survey on Drug Use and Health focusing on adults in the US. Trends in past-year ketamine use, overall and by depression status, were estimated separately for 2015-2019 and 2021-2022 due to methodological changes in the survey. We also delineated correlates of ketamine use in each period, focusing on depression, sociodemographic characteristics, and other past-year drug use.

RESULTS

Overall ketamine use prevalence increased from 2015 to 2019 (from 0.11 % to 0.20 %, an 81.8 % increase, p < 0.01) and from 2021 to 2022 (from 0.20 % to 0.28 %, a 40.0 % increase, p < 0.05). From 2015 to 2019, use increased among adults with and without depression (by 139.3 % [p < 0.05] and 66.7 % [p < 0.05], respectively), while from 2021 to 2022, an increase occurred only among those without depression (by 38.9 %, p < 0.05). Multivariable models revealed that depression was associated with increased odds of ketamine use in 2015-2019 (aOR = 1.80, 95 % CI: 1.12-2.89) but not in later years. New sociodemographic correlates emerged in 2021-2022, including adults aged 26-34 and those with a college degree being at higher odds for use. Various drugs (especially ecstasy/MDMA and gamma-hydroxybutyrate) were consistently associated with higher odds of use.

CONCLUSION

We identified differential patterns and correlates of ketamine use over time. Shifts may be related to the evolving ketamine landscape and/or changing survey methodology. Monitoring of use patterns is crucial to inform prevention and harm reduction strategies.

Cognitive changes in patients with unipolar TRD treated with IV ketamine: A systematic review

BACKGROUND

Unipolar treatment-resistant depression (MDD-TRD) is associated with neurocognitive impairment. Ketamine, an emerging treatment for MDD-TRD, may have neurocognitive benefits, but evidence remains limited.

METHODS

We conducted a systematic search on EMBASE, Google Scholar, PsycINFO, and PubMed and included studies exploring the cognitive effects of intravenous (IV) ketamine treatment in the management of MDD-TRD following the PRISMA guidelines. We analyzed cognitive scale score changes pre- and post-IV ketamine treatment and the quality of the evidence using the Cochrane risk of bias tool and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE).

RESULTS

Out of 1171 identified studies, fourteen studies were included in this study. Most studies reported positive cognitive outcomes post-ketamine treatment, including improvements in processing speed, working memory, verbal and visual memory, executive function, attention, emotional processing, and auditory verbal episodic memory. Variability existed, with one study reporting negative effects on verbal memory. Overall, studies exhibited a low risk of bias.

LIMITATIONS

Several limitations impacted the results observed, including confining our scope to articles in English, heterogeneity of the included studies, small sample sizes, and the predominance of a female, Western, and Caucasian population, constraining the generalizability of the findings.

CONCLUSIONS

IV ketamine treatment shows promise in improving neurocognitive function in MDD-TRD patients. However, further research is warranted to elucidate long-term effects, control for confounders such as concomitant medications, and explore neurocognitive subgroups within the TRD population. These findings underscore the need for comprehensive assessment and management of cognitive symptoms in TRD, informing future clinical practice.

KETAMINE: Neural- and network-level changes

Ketamine is a widely used clinical drug that has several functional and clinical applications, including its use as an anaesthetic, analgesic, anti-depressive, anti-suicidal agent, among others. Among its diverse behavioral effects, it influences short-term memory and induces psychedelic effects. At the neural level across different brain areas, it modulates neural firing rates, neural tuning, brain oscillations, and modularity, while promoting hypersynchrony and random connectivity between neurons. In our recent studies we demonstrated that topical application of ketamine on the visual cortex alters neural tuning and promotes vigorous connectivity between neurons by decreasing their firing variability. Here, we begin with a brief review of the literature, followed by results from our lab, where we synthesize a dendritic model of neural tuning and network changes following ketamine application. This model has potential implications for focused modulation of cortical networks in clinical settings. Finally, we identify current gaps in research and suggest directions for future studies, particularly emphasizing the need for more animal experiments to establish a platform for effective translation and synergistic therapies combining ketamine with other protocols such as training and adaptation. In summary, investigating ketamine's broader systemic effects, not only provides deeper insight into cognitive functions and consciousness but also paves the way to advance therapies for neuropsychiatric disorders.

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.

Efficacy of ketamine versus esketamine in the treatment of perioperative depression: A review

Depression is a significant factor contributing to postoperative occurrences, and patients diagnosed with depression have a higher risk for postoperative complications. Studies on cardiovascular surgery extensively addresses this concern. Several studies report that people who undergo coronary artery bypass graft surgery have a 20% chance of developing postoperative depression. A retrospective analysis of medical records spanning 21 years, involving 817 patients, revealed that approximately 40% of individuals undergoing coronary artery bypass grafting (CABG) were at risk of perioperative depression. Patients endure prolonged suffering from illness because each attempt with standard antidepressants requires several weeks to be effective. In addition, multi-drug combination adjuvants or combination medication therapy may alleviate symptoms for some individuals, but they also increase the risk of side effects. Conventional antidepressants primarily modulate the monoamine system, whereas different therapies target the serotonin, norepinephrine, and dopamine systems. Esketamine is a fast-acting antidepressant with high efficacy. Esketamine is the S-enantiomer of ketamine, a derivative of phencyclidine developed in 1956. Esketamine exerts its effect by targeting the glutaminergic system the glutaminergic system. In this paper, we discuss the current depression treatment strategies with a focus on the pharmacology and mechanism of action of esketamine. In addition, studies reporting use of esketamine to treat perioperative depressive symptoms are reviwed, and the potential future applications of the drug are presented.

Canadian Network for Mood and Anxiety Treatments (CANMAT) 2023 Update on Clinical Guidelines for Management of Major Depressive Disorder in Adults: Réseau canadien pour les traitements de l'humeur et de l'anxiété (CANMAT) 2023 : Mise à jour des lignes directrices cliniques pour la prise en charge du trouble dépressif majeur chez les adultes

BACKGROUND

The Canadian Network for Mood and Anxiety Treatments (CANMAT) last published clinical guidelines for the management of major depressive disorder (MDD) in 2016. Owing to advances in the field, an update was needed to incorporate new evidence and provide new and revised recommendations for the assessment and management of MDD in adults.

METHODS

CANMAT convened a guidelines editorial group comprised of academic clinicians and patient partners. A systematic literature review was conducted, focusing on systematic reviews and meta-analyses published since the 2016 guidelines. Recommendations were organized by lines of treatment, which were informed by CANMAT-defined levels of evidence and supplemented by clinical support (consisting of expert consensus on safety, tolerability, and feasibility). Drafts were revised based on review by patient partners, expert peer review, and a defined expert consensus process.

RESULTS

The updated guidelines comprise eight primary topics, in a question-and-answer format, that map a patient care journey from assessment to selection of evidence-based treatments, prevention of recurrence, and strategies for inadequate response. The guidelines adopt a personalized care approach that emphasizes shared decision-making that reflects the values, preferences, and treatment history of the patient with MDD. Tables provide new and updated recommendations for psychological, pharmacological, lifestyle, complementary and alternative medicine, digital health, and neuromodulation treatments. Caveats and limitations of the evidence are highlighted.

CONCLUSIONS

The CANMAT 2023 updated guidelines provide evidence-informed recommendations for the management of MDD, in a clinician-friendly format. These updated guidelines emphasize a collaborative, personalized, and systematic management approach that will help optimize outcomes for adults with MDD.

Efficacy and safety of eight enhanced therapies for treatment-resistant depression: A systematic review and network meta-analysis of RCTs

BACKGROUND

Treatment-Resistant Depression (TRD) challenges psychiatric treatment, with existing guidelines covering only a subset of augmentation strategies.

METHODS

A network meta-analysis following PRISMA guidelines examined the efficacy and safety of TRD treatments, analyzing 72 randomized controlled trials from eight databases, assessing response and remission rates, tolerability, and safety through the Cochrane Risk of Bias Tool and CINeMA framework.

FINDINGS

Including 12,105 participants, the analysis highlighted ECT, Ketamine, Esketamine, and Psilocybin as superior first-line treatments due to their optimal balance between effectiveness and tolerability. Brexpiprazole and Quetiapine showed no significant efficacy over placebo in response rates, while Esketamine and Psilocybin exhibited lower tolerability.

INTERPRETATION

The results advocate for ECT, Ketamine, Esketamine, and Psilocybin as preferred treatments for TRD, guiding clinical practice with evidence-based recommendations for enhancing treatment outcomes. This study underscores the importance of considering both efficacy and safety in selecting augmentation strategies for TRD.

Blood pressure changes during ketamine infusion for the treatment of depression

OBJECTIVE

This study aimed to examine blood pressure changes during ketamine infusion for depression and exploring the factors associated with these changes.

METHOD

This study is a retrospective chart-review of patients with depression undergoing ketamine infusion at Yale Psychiatry Hospital during a 7-year period. Blood pressure (BP) was recorded every 10 min during the infusion. Surges in systolic and diastolic blood pressure (SBP, DBP), along with severe hypertension events, were analyzed in relation to patient demographics.

RESULTS

A total of 138 patients received a total of 2342 infusions. SBP and DBP peaked at 40 min after the start of the infusion with a mean change of 16.0 (SD: 11.2) and 11.0 mmHg (SD: 8.45) respectively. Severe hypertension was observed in 17 patients (12.5%) and 23 infusion sessions (0.98%), occuring more frequently during the first three infusions (43.4%). Age (OR = 1.04 [1.02,1.05], p-value <0.001) was significantly associated with a surge in SBP and all patients with a past medical history of hypertension experienced a BP surge during their infusions.

CONCLUSION

Ketamine infusions can cause significant blood pressure increases, particularly in older and hypertensive patients, highlighting the need for careful cardiovascular monitoring to mitigate risks during treatment.

Non-improvement predicts subsequent non-response to repeated-dose intravenous ketamine for depression: a re-analysis of a 2-week open-label study in patients with unipolar and bipolar depression

There is insufficient evidence to guide dose and frequency optimization with repeated-dose ketamine for depression. This study assessed the value of symptomatic non-improvement after the first few ketamine infusions as a predictor of overall non-response in depression for early decision-making to discontinue treatment. A total of 135 individuals with major depressive disorder or bipolar disorder experiencing a current major depressive episode were administered six repeated doses of intravenous ketamine. Depressive symptoms were assessed using the Montgomery-Åsberg Depression Rating Scale (MADRS) at baseline, 4 h after the first infusion, and 24 h after each infusion. Improvement, partial response, and response were defined as a reduction rate of ≥ 20%, 30%, and 50% in MADRS scores, respectively. This study examined the relationship between improvement (as opposed to non-improvement after each infusion or consecutive non-improvements after the first few infusions) and partial response and response after the sixth infusion. This analysis was summarized using sensitivity, specificity, and other diagnostic test parameters. The sensitivities of improvement at 24 h post-infusion 4 and improvement at 24 h post-infusion 3, vs. three consecutive non-improvements, as predictors for overall partial response and response exceeded 90%. No significant reduction in depressive symptoms was seen in non-improvers following the remaining infusions after the above-identified point. Our study suggests that non-improvement after four infusions, or more conservatively three consecutive non-improvements after three infusions, could serve as a signal of overall non-response to repeated-dose intravenous ketamine for depression and that subsequent treatments would not be warranted.

Recurrent Serotonin Syndrome After Ketamine-assisted Electroconvulsive Therapy: A Case Report and Review of the Literature

Serotonin (5-HT) syndrome (SS) consists of changes in mental status as well as autonomic and neuromuscular changes. Though not well understood, serotonergic pathways have been implicated in the mechanism of action of electroconvulsive therapy (ECT). Ketamine has been used as an induction agent in ECT and as therapy for treatment-resistant depression. Utilizing a case report and literature review, we explored the underlying serotonergic mechanisms of ECT and ketamine by which a syndrome of serotonin toxicity may be precipitated. We describe the case of a 72-year-old woman who developed recurrent SS on 2 occasions in similar circumstances involving the administration of ketamine for ECT. In our literature review, we found 5 cases in which SS was associated with ECT and 1 case linking ketamine to SS. There is emerging evidence that the mechanism of ECT involves 5-HT1A and 5-HT2A receptors, the same receptors that are involved in SS. ECT can transiently increase the permeability of the blood-brain barrier, leading to increased levels of antidepressants in the brain. ECT can, therefore, enhance 5-HT transmission and the likelihood of SS in the presence of serotonergic agents. The effect of ketamine on 5-HT transmission is mediated by the glutamate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor. Ketamine increases α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid activity in the medial prefrontal cortex, which leads to downstream 5-HT release through glutamate. Through this mechanism, ketamine can increase 5-HT transmission, leading to SS. To our knowledge, this is the only case report of recurrent SS with concurrent use of ECT and ketamine. As ketamine is frequently used in ECT and many patients undergoing ECT are on serotonergic medications, it is important to recognize ketamine as a potential risk factor for SS. There is no evidence for added efficacy when combining ECT and ketamine. Thus, one should proceed with caution when combining these treatments. The burgeoning use of ketamine in ambulatory settings makes it necessary to elucidate the risks, which we discuss further. More research is needed into the mechanisms of ketamine and ECT, specifically how the combination of these treatments influence 5-HT levels.

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.

Patient-reported outcomes on sleep quality and circadian rhythm during treatment with intravenous ketamine for treatment-resistant depression

Background

Intravenous (IV) ketamine is a rapid acting antidepressant used primarily for treatment-resistant depression (TRD). It has been suggested that IV ketamine's rapid antidepressant effects may be partially mediated via improved sleep and changes to the circadian rhythm.

Objectives

This study explores IV ketamine's association with changes in patient-reported sleep quality and circadian rhythm in an adult population with TRD.

Methods

Adult patients (18-64 years) with TRD scheduled for IV ketamine treatment were recruited to complete patient rated outcomes measures on sleep quality using the Pittsburgh Sleep Quality Index (PSQI) and circadian rhythm using the Morningness-Eveningness Questionnaire (MEQ). Over a 4-week course of eight ketamine infusions, reports were obtained at baseline (T0), prior to second treatment (T1), prior to fifth treatment (T2), and 1 week after eighth treatment (T3).

Results

Forty participants with TRD (mean age = 42.8, 45% male) were enrolled. Twenty-nine (72.5%) had complete follow-up data. Paired t tests revealed statistically significant improvements at the end of treatment in sleep quality (PSQI) (p = 0.003) and depressive symptoms (Clinically Useful Depression Outcome Scale-Depression, p < 0.001) while circadian rhythm (MEQ) shifted earlier (p = 0.007). The PSQI subscale components of sleep duration (p = 0.008) and daytime dysfunction (p = 0.001) also improved. In an exploratory post hoc analysis, ketamine's impact on sleep quality was more prominent in patients with mixed features, while its chronobiotic effect was prominent in those without mixed features.

Conclusion

IV ketamine may improve sleep quality and advance circadian rhythm in individuals with TRD. Effects may differ in individuals with mixed features of depression as compared to those without. Since this was a small uncontrolled study, future research is warranted.

Clinical outcomes in the biomarkers of ketamine (Bio-K) study of open-label IV ketamine for refractory depression

OBJECTIVE

We conducted an open-label clinical trial ("Bio-K") using IV ketamine for treatment-resistant depression to identify biomarkers linked to remission. Here, we report the clinical efficacy and side effect outcomes of Bio-K.

METHODS

Across 4 US sites, 75 patients ages 18-65 with treatment-refractory unipolar or bipolar depression received 3 IV ketamine infusions over an 11-day period. Key exclusion criteria were psychotic symptoms, significant substance abuse, unstable medical conditions, and any use of cannabis. Pre-existing antidepressant medication was maintained. Primary outcome was remission as measured by Montgomery-Asberg Depression Rating Scale (MADRS), with secondary outcome of 50 % reduction in Beck Suicide Scale score. Safety monitoring and varying durations of infusions were also key parameters.

RESULTS

Using remission as MADRS score <10, after 3 infusions 52 % achieved remission, with 67 % achieving response. Of those achieving response after a single infusion, 66 % (22 of 33) reached remission after 3 infusions, while 40 % (16 of 40) non-responders after the first infusion went on to achieve remission after 3 infusions. Only 20 % of non-responders after 2 infusions achieved remission. Most (81 %) participants had significant suicidal ideation at baseline; of these, two-thirds (67 %) experienced at least a 50 % reduction in suicidality. Side effects were minimal. Uniquely, we had three different types of infusion categories, with individuals receiving: (1) slow (100-min) infusions only or (2) regular (40-min) infusions only or (3) a mix of infusion durations. These three infusion groups showed comparable safety and efficacy. Exploration of clinical factors revealed no link between BMI, age, or gender to remission.

CONCLUSIONS

The consistency of outcomes across 4 clinical sites and across multiple instruments, suggests high acute efficacy and safety of IV ketamine for serious depressive episodes. Duration of infusion did not alter outcomes. Meaningfully, 40 % of non-responders after a single infusion did reach remission subsequently, while only 20 % of non-responders after 2 infusions achieved remission, suggesting early response is suggestive for eventual remission. Our data on varying ketamine infusion duration adds novel insights into the clinical administration of this new treatment for refractory and severe patients. Our limitations included a lack of a control group, necessitating caution about conclusions of efficacy, balanced by the utility of reporting "real-world" outcomes across multiple clinical sites. We could also not separately analyze results for bipolar disorder due to small numbers. Together, the Bio-K clinical results are promising and provide significant sample sizes for forthcoming biological markers analyses.

A computational model to characterize the time-course of response to rapid antidepressant therapies

Our objective is to propose a method capable of disentangling the magnitude, the speed, and the duration or decay rate of the time course of response to rapid antidepressant therapies. To this end, we introduce a computational model of the time course of response to a single treatment with a rapid antidepressant. Numerical simulation is used to evaluate whether model parameters can be accurately estimated from observed data. Finally, we compare our computational modelling-based approach with linear mixed effects modelling in terms of their ability to detect changes in the magnitude and time-course of response to rapid antidepressant therapies in simulated randomized trials. Simulation experiments show that the parameters of our computational model can be accurately recovered using nonlinear least squares. Parameter estimation accuracy is stable over noise levels reaching as high as 25% of the true antidepressant effect magnitude. Comparison of our approach to mixed effects modelling using simulated randomized controlled trial data demonstrates an inability of linear mixed models to disentangle effect magnitude and time course, while our computational model accurately separates these response components. Our modelling approach may accurately identify the (A) magnitude, (B) speed, and (C) durability or decay rate of response to rapid antidepressant therapies. Future studies should fit this model to data from real clinical trials, and use resulting parameter estimates to uncover predictors and causes of different elements of the temporal course of antidepressant response.

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.

Ketamine promptly normalizes excess norepinephrine and enhances dopamine neuronal activity in Wistar Kyoto rats

Ketamine acts primarily by blocking the N-methyl-D-aspartate (NMDA) receptor at the phencyclidine site. The rapid antidepressant properties of ketamine were demonstrated in the clinic and several behavioral models of depression in rodents. We hypothesized that the normalization of abnormal activity of monoamine neurons in Wistar Kyoto (WKY) rats contributes to the rapid antidepressant effects of ketamine. A single administration of ketamine (10 mg/kg, i. p) or saline was administered to anesthetized WKY rats before in vivo electrophysiological recordings of dorsal raphe nucleus (DRN) serotonin (5-HT), locus coeruleus (LC) norepinephrine (NE) and ventral tegmental area (VTA) dopamine (DA) neuronal activity. Pyramidal neurons from the medial prefrontal cortex (mPFC) were also recorded before and after a ketamine injection. In the VTA, ketamine elicited a significant increase in the population activity of DA neurons. This enhancement was consistent with findings in other depression-like models in which such a decreased population activity was observed. In the LC, ketamine normalized increased NE neuron burst activity found in WKY rats. In the DRN, ketamine did not significantly reverse 5-HT neuronal activity in WKY rats, which is dampened compared to Wistar rats. Ketamine did not significantly alter the neuronal activity of mPFC pyramidal neurons. These findings demonstrate that ketamine normalized NE neuronal activity and enhanced DA neuronal activity in WKY rats, which may contribute to its rapid antidepressant effect.

Intranasal ketamine as a treatment for psychiatric complications of long COVID: A case report

Background

Neuropsychiatric symptoms associated with long COVID are a growing concern. A proposed pathophysiology is increased inflammatory mediators. There is evidence that typical serotonergic antidepressants have limited efficacy in the presence of inflammation. Although ketamine has shown promise in MDD, there is limited evidence supporting the use of ketamine to treat depressive symptoms associated with long COVID.

Case Report

This case took place on an inpatient psychiatry unit in a Canadian hospital. The patient was admitted with a 10-month history of worsening depression and suicidality following infection with COVID-19. Depressive symptoms and suicidal ideation were assessed throughout treatment using the Montgomery-Asberg Depression Rating Scale (MADRS). Written informed consent was obtained prior to data collection. This patient received 4 doses of intranasal ketamine which resulted in rapid improvement of depressive symptoms and complete resolution of suicidality with no major adverse events.

Discussion

There is evidence to support long COVID symptoms result from dysregulated inflammatory processes. The presence of inflammation in patients with MDD has correlated to poor outcomes with first-line antidepressants. It has been demonstrated that IV ketamine is associated with decreased inflammatory mediators and proportional decrease in depressive symptoms.

Conclusions

Intranasal ketamine in this case was effective at treating depressive symptoms and suicidal ideation associated with long COVID. This is consistent with available data that demonstrates ketamine's efficacy in reducing inflammatory mediators associated with neuropsychiatric symptoms. Therefore, ketamine may be a potential therapeutic option to treat long COVID and persistent depressive symptoms.

The Montreal model: an integrative biomedical-psychedelic approach to ketamine for severe treatment-resistant depression

Background

Subanesthetic ketamine has accumulated meta-analytic evidence for rapid antidepressant effects in treatment-resistant depression (TRD), resulting in both excitement and debate. Many unanswered questions surround ketamine's mechanisms of action and its integration into real-world psychiatric care, resulting in diverse utilizations that variously resemble electroconvulsive therapy, conventional antidepressants, or serotonergic psychedelics. There is thus an unmet need for clinical approaches to ketamine that are tailored to its unique therapeutic properties.

Methods

This article presents the Montreal model, a comprehensive biopsychosocial approach to ketamine for severe TRD refined over 6 years in public healthcare settings. To contextualize its development, we review the evidence for ketamine as a biomedical and as a psychedelic treatment of depression, emphasizing each perspectives' strengths, weaknesses, and distinct methods of utilization. We then describe the key clinical experiences and research findings that shaped the model's various components, which are presented in detail.

Results

The Montreal model, as implemented in a recent randomized clinical trial, aims to synergistically pair ketamine infusions with conventional and psychedelic biopsychosocial care. Ketamine is broadly conceptualized as a brief intervention that can produce windows of opportunity for enhanced psychiatric care, as well as powerful occasions for psychological growth. The model combines structured psychiatric care and concomitant psychotherapy with six ketamine infusions, administered with psychedelic-inspired nonpharmacological adjuncts including rolling preparative and integrative psychological support.

Discussion

Our integrative model aims to bridge the biomedical-psychedelic divide to offer a feasible, flexible, and standardized approach to ketamine for TRD. Our learnings from developing and implementing this psychedelic-inspired model for severe, real-world patients in two academic hospitals may offer valuable insights for the ongoing roll-out of a range of psychedelic therapies. Further research is needed to assess the Montreal model's effectiveness and hypothesized psychological mechanisms.

Practical pathway for the management of depression in the workplace: a Canadian perspective

Major depressive disorder (MDD) and other mental health issues pose a substantial burden on the workforce. Approximately half a million Canadians will not be at work in any week because of a mental health disorder, and more than twice that number will work at a reduced level of productivity (presenteeism). Although it is important to determine whether work plays a role in a mental health condition, at initial presentation, patients should be diagnosed and treated per appropriate clinical guidelines. However, it is also important for patient care to determine the various causes or triggers including work-related factors. Clearly identifying the stressors associated with the mental health disorder can help clinicians to assess functional limitations, develop an appropriate care plan, and interact more effectively with worker's compensation and disability programs, as well as employers. There is currently no widely accepted tool to definitively identify MDD as work-related, but the presence of certain patient and work characteristics may help. This paper seeks to review the evidence specific to depression in the workplace, and provide practical tips to help clinicians to identify and treat work-related MDD, as well as navigate disability issues.

Major depressive disorder

Major depressive disorder (MDD) is characterized by persistent depressed mood, loss of interest or pleasure in previously enjoyable activities, recurrent thoughts of death, and physical and cognitive symptoms. People with MDD can have reduced quality of life owing to the disorder itself as well as related medical comorbidities, social factors, and impaired functional outcomes. MDD is a complex disorder that cannot be fully explained by any one single established biological or environmental pathway. Instead, MDD seems to be caused by a combination of genetic, environmental, psychological and biological factors. Treatment for MDD commonly involves pharmacological therapy with antidepressant medications, psychotherapy or a combination of both. In people with severe and/or treatment-resistant MDD, other biological therapies, such as electroconvulsive therapy, may also be offered.

Antidepressant mechanisms of ketamine: a review of actions with relevance to treatment-resistance and neuroprogression

Concurrent with recent insights into the neuroprogressive nature of depression, ketamine shows promise in interfering with several neuroprogressive factors, and has been suggested to reverse neuropathological patterns seen in depression. These insights come at a time of great need for novel approaches, as prevalence is rising and current treatment options remain inadequate for a large number of people. The rapidly growing literature on ketamine's antidepressant potential has yielded multiple proposed mechanisms of action, many of which have implications for recently elucidated aspects of depressive pathology. This review aims to provide the reader with an understanding of neuroprogressive aspects of depressive pathology and how ketamine is suggested to act on it. Literature was identified through PubMed and Google Scholar, and the reference lists of retrieved articles. When reviewing the evidence of depressive pathology, a picture emerges of four elements interacting with each other to facilitate progressive worsening, namely stress, inflammation, neurotoxicity and neurodegeneration. Ketamine acts on all of these levels of pathology, with rapid and potent reductions of depressive symptoms. Converging evidence suggests that ketamine works to increase stress resilience and reverse stress-induced dysfunction, modulate systemic inflammation and neuroinflammation, attenuate neurotoxic processes and glial dysfunction, and facilitate synaptogenesis rather than neurodegeneration. Still, much remains to be revealed about ketamine's antidepressant mechanisms of action, and research is lacking on the durability of effect. The findings discussed herein calls for more longitudinal approaches when determining efficacy and its relation to neuroprogressive factors, and could provide relevant considerations for clinical implementation.

Efficacy of repeated intravenous esketamine in adolescents with anxious versus non-anxious depression

Background

Patients with anxious major depressive disorder (MDD) are more likely to have poorer outcomes than those with non-anxious MDD. However, the effect of esketamine on adolescents with anxious versus non-anxious MDD has remained unknown.

Aims

We compared the efficacy of esketamine in adolescents with MDD and suicidal ideation, both anxious and non-anxious.

Methods

Fifty-four adolescents with anxious (n=33) and non-anxious (n=21) MDD received three infusions of esketamine 0.25 mg/kg or active-placebo (midazolam 0.045 mg/kg) over 5 days, with routine inpatient care and treatment. Suicidal ideation and depressive symptoms were assessed using the Columbia Suicide Severity Rating Scale and the Montgomery-Åsberg Depression Rating Scale. Multiple-sample proportional tests were used to compare the differences between groups on treatment outcomes 24 hours after the final infusion (day 6, primacy efficacy endpoint) and throughout the 4-week post-treatment (days 12, 19 and 33).

Results

In subjects who received esketamine, a greater number of patients in the non-anxious group than the anxious group achieved antisuicidal remission on day 6 (72.7% vs 18.8%, p=0.015) and day 12 (90.9% vs 43.8%, p=0.013), and the non-anxious group had a higher antidepressant remission rate compared with the anxious group on day 33 (72.7% vs 26.7%, p=0.045). No significant differences in treatment outcomes were observed between the anxious and non-anxious groups at other time points.

Conclusions

Three infusions of esketamine as an adjunct to routine inpatient care and treatment had a greater immediate post-treatment antisuicidal effect in adolescents with non-anxious MDD than in those with anxious MDD; however, this benefit was temporary and was not maintained over time.

Trial registration number

ChiCTR2000041232.

Intravenous ketamine for treatment-resistant depression patients who have failed to respond to transcranial magnetic stimulation: A case series

BACKGROUND

For individuals with treatment-resistant depression (TRD), transcranial magnetic stimulation (TMS) has become a well-established approach. In the past decade, intravenous (IV) racemic ketamine has also emerged as a potential treatment for TRD. Currently, little data is available on the clinical effects of IV racemic ketamine in TRD patients who experienced TMS-failure.

METHODS

Twenty-one (21) TRD patients who had failed to respond to a standard course of high-frequency left-dorsolateral prefrontal cortex TMS were subsequently scheduled to received IV racemic ketamine infusions. The IV racemic ketamine protocol consisted of 0,5 mg/kg infusions over 60 min, 3 times a week over 2 weeks.

RESULTS

Treatment was safe with minimal side-effects. Mean baseline MADRS score was 27.6 ± 6.4 (moderate depression), decreasing down to 18.6 ± 8.9 (mild depression) post-treatment. Mean percent improvement was 34.5 % ± 21.1 from baseline to post-treatment. Paired sample t-test showed significant MADRS score decrease pre- to post-treatment [t(20) = 7.212, p < .001]. Overall, four (4) patients (19.0 %) responded and two (2) of those achieved remission (9.5 %).

LIMITATIONS

Limitations of this case series include its retrospective and uncontrolled open-label nature, the lack of self-rating and standardized adverse events questionnaires, as well as follow-ups beyond the immediate treatment period.

CONCLUSIONS

Novel ways to increase the clinical effects of ketamine are being explored. We discuss potential combination approaches of ketamine with other modalities to augment its effects. Given the global burden of TRD, novel approaches are needed to curb the current mental health epidemic around the world.

Brain-derived neurotrophic factor serum levels following ketamine and esketamine intervention for treatment-resistant depression: secondary analysis from a randomized trial

OBJECTIVES

Evidence suggests that ketamine's influence on brain-derived neurotrophic factor (BDNF) might be involved in its mechanism of rapid antidepressant action. We aimed to evaluate the differential impact of ketamine and esketamine on serum BDNF levels and its association with response patterns in treatment-resistant depression (TRD).

METHODS

Participants (n = 53) are from a randomized, double-blind clinical trial comparing the efficacy of single-dose ketamine (0.5mg/kg, n = 27) and esketamine (0.25mg/kg, n = 26) in TRD. Depression severity was assessed before and 24 hours, 72 hours, and 7 days after the intervention, using the Montgomery-Åsberg Depression Rating Scale (MADRS). Blood samples were collected before infusion, 24 hours, and 7 days afterwards.

RESULTS

There were no significant changes in BDNF levels at post-infusion evaluation points, and no difference in BDNF levels comparing ketamine and esketamine. Both drugs exhibited similar therapeutic effect. There was no association between BDNF levels and response to treatment or severity of depressive symptoms.

CONCLUSION

There was no significant treatment impact on BDNF serum levels - neither with ketamine nor esketamine - despite therapeutic response. These results suggest that ketamine or esketamine intervention for TRD has no impact on BDNF levels measured at 24 hours and 7 days after the infusion.

Patients' recovery and non-recovery narratives after intravenous ketamine for treatment-resistant depression

BACKGROUND

Intravenous (IV) ketamine is an effective therapy for treatment-resistant depression. A large data base is confirmatory and steadily expanding. Qualitative studies can inform best practices and suggest new research directions. As part of a clinical trial designed to identify biomarkers of ketamine response, a qualitative study was conducted to characterize experiences with: receiving infusions; recovering or not recovering from depression; and beliefs about why ketamine worked or did not work.

METHODS

Adults with treatment-resistant depression received three IV ketamine infusions in a two-week period and were characterized as remitters or non-remitters via symptom reduction 24 h after the third infusion. Qualitative interviews of a subset of participants were audio recorded, transcribed verbatim, and coded using deductive and inductive methods. Themes were derived and compared across a broader construct of recovery status.

RESULTS

Of the 21 participants, nine (43 %) were characterized as having experienced remission and 12 (57 %) non-remission. Of the 12 non-remitters, five were characterized as having experienced partial recovery based on their subjective experiences, reporting substantial benefit from ketamine infusions despite non-remission status based on scale measurements. Attributions for ketamine's effects included biological and experiential mechanisms. Among non-remitters there was risk of disappointment when adding another failed treatment.

LIMITATIONS

A more diverse sample may have yielded different themes. Different patients had different amounts of time elapsed between ketamine infusions and qualitative interview.

CONCLUSIONS

Qualitative methods may enhance researchers' characterization of IV ketamine's impact on treatment-resistant depression. While requiring confirmation, patients may benefit from a preparatory milieu that prepares them for multiple recovery pathways; decouples the psychedelic experience from clinical outcomes; and addresses potential risks of another failed treatment.

Ketamine and esketamine in suicidal thoughts and behaviors: a systematic review

BACKGROUND

More than 2% of the general population experience suicidal ideas each year and a large number of them will attempt suicide. Evidence-based therapeutic options to manage suicidal crisis are currently limited.

OBJECTIVES

The aim of this study was to overview the findings on the use of ketamine and esketamine for the treatment of suicidal ideas and acts.

DESIGN

Systematic review.

DATA SOURCES AND METHODS

PubMed, article references, and Clinicaltrials.gov up to June 30, 2022. Meta-analyses published within the last 2 years were also reviewed.

RESULTS

We identified 12 randomized controlled trials with reduction of suicidal ideation as the primary objective and 14 trials as secondary objectives. Intravenous racemic ketamine was superior to control drugs (placebo or midazolam) within the first 72 h, in spite of large placebo effects. Adverse events were minor and transient. In contrast, intranasal esketamine did not differ from placebo in large-scale studies. Limitations, clinical considerations, and opportunities for future research include the following points: large placebo effects when studying suicidal ideation reduction; small concerns about blinding quality due to dissociative effects; no studies on the risk/prevention of suicidal acts and mortality; lack of studies beyond affective disorders; no studies in adolescents and older people; lack of knowledge of long-term side effects, notably liability for abuse; no robust predictive markers; limited understanding of the mechanisms of ketamine on suicidal ideas; need for improved assessment of suicidal ideation in clinical trials; need for studies in outpatient settings, emergency room, and liaison consultation; need for research on ketamine administration; limited knowledge on the positive and negative effects of concomitant treatments.

CONCLUSION

Overall, there is compelling evidence for a favorable short-term benefit-risk balance with intravenous racemic ketamine but not intranasal esketamine. The place of ketamine will have to be defined within a multimodal care strategy for suicidal patients. Caution remains necessary for clinical use, and pharmacovigilance will be essential.

The Canadian Network for Mood and Anxiety Treatments (CANMAT) Task Force Report: Serotonergic Psychedelic Treatments for Major Depressive Disorder

OBJECTIVE

Serotonergic psychedelics are re-emerging as potential novel treatments for several psychiatric disorders including major depressive disorder. The Canadian Network for Mood and Anxiety Treatments (CANMAT) convened a task force to review the evidence and provide a consensus recommendation for the clinical use of psychedelic treatments for major depressive disorder.

METHODS

A systematic review was conducted to identify contemporary clinical trials of serotonergic psychedelics for the treatment of major depressive disorder and cancer-related depression. Studies published between January 1990 and July 2021 were identified using combinations of search terms, inspection of bibliographies and review of other psychedelic reviews and consensus statements. The levels of evidence for efficacy were graded according to the Canadian Network for Mood and Anxiety Treatments criteria.

RESULTS

Only psilocybin and ayahuasca have contemporary clinical trials evaluating antidepressant effects. Two pilot studies showed preliminary positive effects of single-dose ayahuasca for treatment-resistant depression (Level 3 evidence). Small randomized controlled trials of psilocybin combined with psychotherapy showed superiority to waitlist controls and comparable efficacy and safety to an active comparator (escitalopram with supportive psychotherapy) in major depressive disorder, with additional randomized controlled trials showing efficacy specifically in cancer-related depression (Level 3 evidence). There was only one open-label trial of psilocybin in treatment-resistant unipolar depression (Level 4 evidence). Small sample sizes and functional unblinding were major limitations in all studies. Adverse events associated with psychedelics, including psychological (e.g., psychotomimetic effects) and physical (e.g., nausea, emesis and headaches) effects, were generally transient.

CONCLUSIONS

There is currently only low-level evidence to support the efficacy and safety of psychedelics for major depressive disorder. In Canada, as of 2022, psilocybin remains an experimental option that is only available through clinical trials or the special access program. As such, Canadian Network for Mood and Anxiety Treatments considers psilocybin an experimental treatment and recommends its use primarily within clinical trials, or, less commonly, through the special access program in rare, special circumstances.

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.

Efficacy of ketamine for comorbid depression and acute or chronic pain: A systematic review

Pain and depression frequently co-occur. Due to its antidepressant and analgesic properties, ketamine has been used for the management of treatment-resistant depression and pain. This systematic review examined the literature on the efficacy of sub-anesthetic doses of ketamine in individuals experiencing comorbid depression and chronic pain (CDCP), as well as comorbid depression and acute pain (CDAP). A secondary objective was to provide an assessment of dosage, route, and adverse effects of ketamine treatment for CDCP and CDAP. A literature search was conducted on MEDLINE, PsycINFO, and Embase databases, coupled with a manual screening of the bibliography sections of included articles. In addition, registered ongoing and planned trials were searched on Clinicaltrials.gov. The end date of the search was April 9th, 2022. Included studies assessed changes in depression and pain in patients receiving at least one sub-anesthetic dose of ketamine. Assessment of quality was conducted using the GRADE checklist. Of the 7 CDCP clinical trials, 3 reported a reduction in depression and pain, 3 reported a reduction in depression or pain only, and 1 reported no improvement in either comorbidity. Among the 7 CDAP clinical trials, 4 studies found improvements in depression and pain while the remaining 3 reported improvements in only one parameter. Ten of the 12 case studies and 2 of the 3 observational studies assessing CDCP and CDAP found improvements in pain and depression scores post-treatment with effects of variable duration. The planned methodologies of the registered clinical trials are in line with those of the published research. Preliminary evidence supports the efficacy of ketamine in treating CDCP and CDAP. However, the current review identified a small number of heterogeneous studies with mixed results, preventing comprehensive conclusions. More longitudinal placebo-controlled studies are needed to identify the effects of ketamine for patients with CDCP and CDAP.

Effects of GRIN2B, GRIA1, and BDNF Polymorphisms on the Therapeutic Action of Ketamine and Esketamine in Treatment-Resistant Depression Patients: Secondary Analysis From a Randomized Clinical Trial

OBJECTIVE

This study aimed to evaluate the effect of genetic variants in glutamate ionotropic receptor N-methyl-d-aspartate type subunit 2B (GRIN2B), glutamate ionotropic receptor α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid type subunit 1 (GRIA1), and brain-derived neurotrophic factor (BDNF) genes on therapeutic response, remission, and total Montgomery-Åsberg Depression Rating Scale scores after treatment with ketamine or esketamine in treatment-resistant depression (TRD) patients.

METHODS

Participants (N = 60) are from a double-blind, randomized, noninferiority clinical trial comparing single-dose intravenous ketamine (0.5 mg/kg) to esketamine (0.25 mg/kg) for TRD. Montgomery-Åsberg Depression Rating Scale was applied at baseline, 24 hours, 72 hours, and 7 days postinfusion to assess depressive symptoms. Blood samples were collected to evaluate single nucleotide polymorphisms rs1805502 (GRIN2B), rs1994862 (GRIA1), and rs6265 (BDNF).

RESULTS

There was no association between rs1805502, rs1994862, or rs6265 polymorphisms and antidepressant response (P = 0.909, P = 0.776, and P = 0.482, respectively), remission P = 0.790, P = 0.086, and P = 0.669), or Montgomery-Åsberg Depression Rating Scale scores at each time point (P = 0.907, P = 0.552, and P = 0.778).

CONCLUSIONS

We found no association between the studied single nucleotide polymorphisms (rs6265, rs1805502, and rs1994862) and ketamine's therapeutic action in TRD patients. Further studies with larger samples are needed to clarify the utility of these genes of interest as predictors for antidepressant treatment.

Prescribing behavior of antidepressants for depressive disorders: A systematic review

Objective

Guidelines for the prescription of antidepressants for Depressive Disorders (DD) have been in place for a long time. However, there is a lack of systematic information on the prescribing behavior of antidepressants in evidence-based clinical practice in psychopharmacotherapy of depressive disorders. This may suggest a lack of implementation of clinical guidelines by clinicians. Existing literature mainly focuses on specific issues or medications. To provide general information on the prescribing behavior of antidepressants for depressive disorders, a systematic review of available studies since 2013 was conducted.

Methods and materials

To ensure a structured and systematic approach for the literature search and subsequent review process, the PRISMA guidelines for systematic reviews were followed. Major medical and health and psychological databases were used for the literature search. These included Ebsco Host, OVID, PubMed, Science Direct, Scopus, and Web of Science. The online application "Covidence" was employed to manage the titles collected and the full articles retrieved from the initial literature search. Upon finalizing the list of selected studies, data extraction was then conducted using a build-in function of the Covidence platform with the required information pre-set on a template for data extraction. The extracted information was tabulated and summarized in a table.

Results

Forty-one studies were identified after an extensive search of the literature following the PRISMA guidelines. Of these, 37 quantitative studies providing useful information were systematically reviewed and information extracted. There was a high level of heterogeneity among these studies with different foci or characteristics. Most studies were conducted in or utilized data obtained from hospital and primary healthcare settings. SSRIs were the most commonly prescribed type of antidepressant in the past decade, particularly among younger patients. Among these studies, antidepressants were mainly prescribed by psychiatrists with some by other physicians and general practitioners. This might reflect differences in legislation regarding professional requirements for prescribers or clinical practices.

Conclusions

A few themes that would be considered important in terms of the effect of prescription behavior on depression, specifically children/adolescents, special target populations, and off-label prescription. The results highlighted the need for more studies on a community-based approach and the role of GPs in the treatment of DD.

Repeated subcutaneous racemic ketamine in treatment-resistant depression: case series

Interest in the use of parenteral ketamine has been increasing over the last 2 decades for the management of treatment-resistant depression (TRD). While intravenous (IV) ketamine has been the most common parenteral route of administration, subcutaneous (SC) and intramuscular options have been described. We developed a clinical treatment protocol for the use of repeated SC racemic ketamine (maximum six treatments, twice per week) in an inpatient psychiatric care setting with inclusion/exclusion criteria, dosing schedule, and description of treatment, assessment, and monitoring procedures. Results from the first 10 consecutive patients demonstrated the effectiveness of SC racemic ketamine in relieving symptoms of TRD as measured by the Montgomery-Åsberg Depression Rating Scale (MADRS) and Quick Inventory of Depressive Symptomatology, Self-Report (QIDS-SR 16 ). Response (≥50% reduction in scores from baseline to endpoint) was achieved in 8/10 cases on the MADRS and 6/10 on the QIDS-SR 16 . Remission was achieved in 8/10 (based on MADRS ≤10) and 5/10 (based on QIDS-SR 16 ≤6). Patients tolerated the treatments well with only transient blood pressure changes and dissociative side effects. Repeated SC ketamine treatments could be a safe, feasible, and effective alternative to IV ketamine infusions for patients with TRD.

Ketamine for suicidality: An umbrella review

The urgent need for appropriate treatment for suicide, the tenth leading cause of death, has led to numerous studies. This study aims to systematically identify and appraise systematic reviews with or without meta-analyses investigating ketamine in suicidal ideation and behaviours. Scopus, ISI, Embase, PubMed, CINAHL, PsycINFO, Cochrane Library, Google Scholar and two registries were searched without any restrictions for systematic reviews investigating the efficacy of ketamine on suicidal ideation and behaviours. The primary outcome was the final inference of ketamine effectiveness. A formal narrative synthesis was conducted, and the AMSTAR-2 tool was used to evaluate the quality of the studies. Of 27 studies that addressed ketamine for suicidal ideation, only four reported mixed or negative results, and out of nine reviews, esketamine was significantly beneficial only in five. A transient rise in pulse rate and blood pressure, dissociation, confusion, blurred vision, nausea and vertigo were the most common adverse effects; however, most were mild. More than two-thirds of the included studies qualified as of low or critically low quality. Preliminary evidence for the short-term efficacy of ketamine in suicidality was noted by the majority of reviews; however, long-term effects remained unknown. Due to the low quality of many studies and the limitations of core studies, further research is required.

Case report: Effectiveness of brexpiprazole and esketamine/ketamine combination: A novel therapeutic strategy in five cases of treatment-resistant depression

A significant proportion of patients with treatment-resistant depression do not attain functional recovery despite administration of multiple steps of pharmacotherapeutic strategies. This highlights the elusiveness of meeting unmet needs in existing pharmacotherapies for treatment-resistant depression. There is accumulating evidence that antidepressant agents involving the glutamatergic system such as brexpiprazole and esketamine/ketamine have more rapid onset of action and potentially improved effectiveness as an augmentation therapy in treatment-resistant depression. This case series aimed to report five complex cases of unipolar and bipolar treatment-resistant depression where conventional treatment strategies were inadequate in managing high risk suicidal behavior and achieving functional recovery. We discussed further the possible synergistic mechanisms of the novel combination strategy of brexpiprazole and esketamine/ketamine, clinical and patient factors that influenced treatment response, challenges with this combination strategy and implications for future practice and research.

Psychedelics in the treatment of unipolar and bipolar depression

This is a narrative review about the role of classic and two atypical psychedelics in the treatment of unipolar and bipolar depression. Since the 1990s, psychedelics experience a renaissance in biomedical research. The so-called classic psychedelics include lysergic acid diethylamide (LSD), psilocybin, mescaline and ayahuasca. Characteristic effects like alterations in sensory perception, as well as emotion- and self-processing are induced by stimulation of serotonin 2A receptors in cortical areas. The new paradigm of psychedelic-assisted psychotherapy suggests a therapeutic framework in which a safely conducted psychedelic experience is integrated into a continuous psychotherapeutic process. First randomized, controlled trials with psilocybin show promising efficacy, tolerability, and adherence in the treatment of unipolar depression. On the other hand, classic psychedelics seem to be associated with the induction of mania, which is an important issue to consider for the design of research and clinical protocols. So called atypical psychedelics are a heterogeneous group with overlapping subjective effects but different neurobiological mechanisms. Two examples of therapeutic value in psychiatry are 3,4-methyl​enedioxy​methamphetamine (MDMA) and ketamine. Since 2020 the ketamine enantiomer esketamine has been granted international approval for treatment-resistant unipolar depression, and also first evidence exists for the therapeutic efficacy of ketamine in bipolar depression. Whether psychedelics will fulfil current expectations and find their way into broader clinical use will depend on future rigorous clinical trials with larger sample sizes. A well-considered therapeutic and legal framework will be crucial for these substances to create new treatment settings and a potential paradigm shift.

Esketamine for Unipolar Major Depression With Psychotic Features: A Retrospective Chart Review and Comparison With Nonpsychotic Depression

PURPOSES/BACKGROUND

The aims of the study were to assess subanesthetic esketamine as an antidepressant for major depressive disorder with psychotic features (PMDD) and to compare posttreatment symptoms among those with PMDD to a sample of nonpsychotic depression (major depressive disorder [MDD]).

METHODS/PROCEDURES

This study is a retrospective chart review of patients with major depression and current psychotic symptoms, treated with a single parenteral 0.5-mg/kg dose of esketamine. Depression symptoms were assessed at baseline and 24-hour posttreatment with the Montgomery-Åsberg Depression Rating Scale. Individuals with PMDD were matched in a 1:2 ratio to nonpsychotic MDD patients from a randomized, noninferiority clinical trial of esketamine.

FINDINGS/RESULTS

A total of 15 individuals with PMDD were included, which had higher baseline depression scores (PMDD = 40.9, MDD = 33.6, P = 0.004). A statistically significant change in depressive symptoms was found for the PMDD sample (β = -16.20 [95% confidence interval, -23.30 to -9.10], P < 0.001), and no difference between PMDD and MDD groups was observed in the matched-sample analysis (β = -2.2 [95% confidence interval, -9.32 to 4.58], P = 0.537). Treatment-induced dissociative symptoms were present for both groups, self-contained to within 2 hours after treatment, and no exacerbation of psychotic symptoms was found in clinical assessments.

IMPLICATIONS/CONCLUSIONS

Results suggest a single 0.5-mg/kg dose of esketamine may benefit individuals with PMDD, and the symptom reduction may be comparable with esketamine's effects for MDD. Furthermore, esketamine may induce an antidepressant response in those with PMDD without complication of psychotic symptoms. Future research with controlled designs is warranted.

Rapid treatments for depression: Endocannabinoid system as a therapeutic target

Current first-line treatments for major depressive disorder (MDD), i.e., antidepressant drugs and psychotherapy, show delayed onset of therapeutic effect as late as 2-3 weeks or more. In the clinic, the speed of beginning of the actions of antidepressant drugs or other interventions is vital for many reasons. Late-onset means that depression, its related disability, and the potential danger of suicide remain a threat for some patients. There are some rapid-acting antidepressant interventions, such as sleep deprivation, ketamine, acute exercise, which induce a significant response, ranging from a few hours to maximally one week, and most of them share a common characteristic that is the activation of the endocannabinoid (eCB) system. Activation of this system, i.e., augmentation of eCB signaling, appears to have anti-depressant-like actions. This article puts the idea forward that the activation of eCB signaling represents a critical mechanism of rapid-acting therapeutic interventions in MDD, and this system might contribute to the development of novel rapid-acting treatments for MDD.

Ketamine: from prescription anaesthetic to New Psychoactive Substance

Discovered in the United States of America (USA) in the 1960s, ketamine was introduced as an anaesthetic drug to specifically replace phencyclidine. Briefly, the substance moved from the medical world to recreational users, since it was discovered that intense psychedelic experiences were obtained with dosages lower than those prescribed for anesthesia. At the end of the 90's, circulated in London nightclubs as a drug itself and as counterfeit 3,4-methylenedioxymethamphetamine tablets. In 1997, the Drug Enforcement Administration (DEA) alerted the United States (US) government to the increasing diffusion of ketamine in American 'clubs', and in 1999, the substance was added to Schedule III of drugs controlled by federal authorities. In 2002, ketamine epidemics moved to Europe, and the European Monitoring Centre for Drugs and Drug Addiction carried out a risk assessment monitoring of the phenomenon. An estimated ninety-nine percent of all global ketamine seizures occurred in Asia. Its growing popularity is due to the fact that this new psychoactive substance is cheaper than other stimulants such as MDMA that the amount used for recreational purposes does not cause respiratory depression and its legal use as a drug makes it widely available for a diversion towards illicit markets. Nevertheless, acute intoxication and several deaths have been related to exclusive ketamine use both in Europe and internationally. Since 2015, there has been and increasing rise of the illicit ketamine market and currently the drug is being used with unprecedented peaks and a consequent significant increase in seizures and clinical cases worldwide.

Electrophysiological correlates and predictors of the antidepressant response to repeated ketamine infusions in treatment-resistant depression

BACKGROUND

Sub-anesthetic ketamine doses rapidly reduce depressive symptoms, although additional investigations of the underlying neural mechanisms and the prediction of response outcomes are needed. Electroencephalographic (EEG)-derived measures have shown promise in predicting antidepressant response to a variety of treatments, and are sensitive to ketamine administration. This study examined their utility in characterizing changes in depressive symptoms following single and repeated ketamine infusions.

METHODS

Recordings were obtained from patients with treatment-resistant major depressive disorder (MDD) (N = 24) enrolled in a multi-phase clinical ketamine trial. During the randomized, double-blind, crossover phase (Phase 1), patients received intravenous ketamine (0.5 mg/kg) and midazolam (30 μg/kg), at least 1 week apart. For each medication, three resting, eyes-closed recordings were obtained per session (pre-infusion, immediately post-infusion, 2 h post-infusion), and changes in power (delta, theta1/2/total, alpha1/2/total, beta, gamma), alpha asymmetry, theta cordance, and theta source-localized anterior cingulate cortex activity were quantified. The relationships between ketamine-induced changes with early (Phase 1) and sustained (Phases 2,3: open-label repeated infusions) decreases in depressive symptoms (Montgomery-Åsberg Depression Rating Score, MADRS) and suicidal ideation (MADRS item 10) were examined.

RESULTS

Both medications decreased alpha and theta immediately post-infusion, however, only midazolam increased delta (post-infusion), and only ketamine increased gamma (immediately post- and 2 h post-infusion). Regional- and frequency-specific ketamine-induced EEG changes were related to and predictive of decreases in depressive symptoms (theta, gamma) and suicidal ideation (alpha). Early and sustained treatment responders differed at baseline in surface-level and source-localized theta.

CONCLUSIONS

Ketamine exerts frequency-specific changes on EEG-derived measures, which are related to depressive symptom decreases in treatment-resistant MDD and provide information regarding early and sustained individual response to ketamine.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: Action of Ketamine in Treatment-Resistant Depression, NCT01945047.

Ketamine treatment for depression: a review

This manuscript reviews the clinical evidence regarding single-dose intravenous (IV) administration of the novel glutamatergic modulator racemic (R,S)-ketamine (hereafter referred to as ketamine) as well as its S-enantiomer, intranasal esketamine, for the treatment of major depressive disorder (MDD). Initial studies found that a single subanesthetic-dose IV ketamine infusion rapidly (within one day) improved depressive symptoms in individuals with MDD and bipolar depression, with antidepressant effects lasting three to seven days. In 2019, esketamine received FDA approval as an adjunctive treatment for treatment-resistant depression (TRD) in adults. Esketamine was approved under a risk evaluation and mitigation strategy (REMS) that requires administration under medical supervision. Both ketamine and esketamine are currently viable treatment options for TRD that offer the possibility of rapid symptom improvement. The manuscript also reviews ketamine's use in other psychiatric diagnoses-including suicidality, obsessive-compulsive disorder, post-traumatic stress disorder, substance abuse, and social anxiety disorder-and its potential adverse effects. Despite limited data, side effects for antidepressant-dose ketamine-including dissociative symptoms, hypertension, and confusion/agitation-appear to be tolerable and limited to around the time of treatment. Relatively little is known about ketamine's longer-term effects, including increased risks of abuse and/or dependence. Attempts to prolong ketamine's effects with combined therapy or a repeat-dose strategy are also reviewed, as are current guidelines for its clinical use. In addition to presenting a novel and valuable treatment option, studying ketamine also has the potential to transform our understanding of the mechanisms underlying mood disorders and the development of novel therapeutics.

A comparison of the safety, feasibility, and tolerability of ECT and ketamine for treatment-resistant depression

INTRODUCTION

Treatment-resistant depression (TRD) is a problematic and prevalent public health and societal concern. Although electroconvulsive therapy (ECT) is the gold standard TRD intervention, the treatment evokes apprehension due to public perceptions, feasibility, and tolerability. Despite significant medical advancements, few medications have been approved by the U.S. Food and Drug Administration for TRD. In 2019, intranasal esketamine, the S-isomer of racemic ketamine, was approved for TRD, garnering significant excitement about the potential for the drug to act as an alternative treatment to ECT.

AREAS COVERED

The goal of this narrative review is to compare the safety, efficacy, and tolerability of ketamine and ECT; clarify whether ketamine is a reasonable alternative to ECT; and to facilitate improved treatment assignment for TRD. Empirical quantitative and qualitative studies and national and international guidelines these treatments are reviewed.

EXPERT OPINION

: The field awaits the results of two ongoing large comparative effectiveness trials of ECT and IV ketamine for TRD, which should help guide clinicians and patients as to the relative risk and benefit of these interventions. Over the next five years we anticipate further innovations in neuromodulation and in drug development which broadly aim to develop more tolerable versions of ECT and ketamine, respectively.

Patterns of use, clinical efficacy, safety and tolerability of Ketamine and Esketamine in treatment-resistant depression: Towards registry-based surveillance systems

More data on the long-term effects of Racemic Ketamine and Esketamine in TDR patients is needed. The implementation of centralized registries of their use for treatment of depression could be a tool of major importance for assessing their efficacy and safety in real-world clinical practice. This paper seeks to outline the rise and rationale behind these registry-based surveillance systems.

Transcranial magnetic stimulation and intravenous ketamine combination therapy for treatment-resistant bipolar depression: A case report

About a third of patients suffering from major depression develop treatment-resistant depression (TRD). Although repetitive transcranial magnetic stimulation (rTMS) and intravenous ketamine have proven effective for the management of TRD, many patients remain refractory to treatment. We present the case of a patient suffering from bipolar TRD. The patient was referred to us after failure to respond to first-and second-line pharmacotherapy and psychotherapy. After minimal response to both rTMS and ketamine alone, we attempted a combination rTMS and ketamine protocol, which led to complete and sustained remission. Various comparable and complimentary mechanisms of antidepressant action of ketamine and rTMS are discussed, which support further study of this combination therapy. Future research should focus on the feasibility, tolerability, and efficacy of this novel approach.

Intravenous ketamine for depression: A clinical discussion reconsidering best practices in acute hypertension management

Ketamine is a versatile medication with an emerging role for the treatment of numerous psychiatric conditions, including treatment resistant depression. Current psychiatry guidelines for its intravenous administration to treat depression recommend regular blood pressure monitoring and an aggressive approach to potential transient hypertensive episodes induced by ketamine infusions. While this approach is aimed at ensuring patient safety, it should be updated to align with best practice guidelines in the management of hypertension. This review defines and summarizes the currently recommended approach to the hypertensive emergency, the asymptomatic hypertensive urgency, and discusses their relevance to intravenous ketamine therapy. With an updated protocol informed by these best practice guidelines, ketamine treatment for depression may be more accessible to facilitate psychiatric treatment.

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

Intravenous (IV) ketamine is increasingly used off-label at subanesthetic doses for its rapid antidepressant effect, and intranasal (IN) esketamine has been recently approved in several countries for treating depression. The clinical utility of these treatments is limited by a paucity of publicly funded IV ketamine and IN esketamine programs and cost barriers to private treatment programs, as well as the drug cost for IN esketamine itself, which makes generic ketamine alternatives an attractive option. Though evidence is limited, use of non-parenteral racemic ketamine formulations (oral, sublingual, and IN) may offer more realistic access in less rigidly supervised settings, both for acute and maintenance treatment in select cases. However, the psychiatric literature has repeatedly cautioned on the addictive potential of ketamine and raised caution for both less supervised and longer-term use of ketamine. To date, these concerns have not been discussed in view of available evidence, nor have they been discussed within a broader clinical context. This paper examines the available relevant literature and suggests that ketamine misuse risks appear not dissimilar to those of other well-established and commonly prescribed agents with abuse potential, such as stimulants or benzodiazepines. As such, ketamine prescribing should be considered in a similar risk/benefit context to balance patient access and need for treatment with concern for potential substance misuse. Our consortium of mood disorder specialists with significant ketamine prescribing experience considers prescribing of non-parenteral ketamine a reasonable clinical treatment option in select cases of treatment-resistant depression. This paper outlines where this may be appropriate and makes practical recommendations for clinicians in judicious prescribing of non-parenteral ketamine.