Meta-analysis of short- and mid-term efficacy of ketamine in unipolar and bipolar depression

Interventional approaches to treatment resistant depression (DTR) in children and adolescents: A systematic review and meta-analysis

BACKGROUND

Major depressive disorder (MDD) is highly prevalent in youth. Conventional treatment paradigms primarily involve selective serotonin reuptake inhibitors (SSRIs) and psychotherapy, yet a significant proportion of this population exhibits treatment-resistant depression (TRD). In adults, interventional therapies like Electroconvulsive Therapy (ECT), repetitive Transcranial Magnetic Stimulation (rTMS), and ketamine have shown promise for TRD, but their comparative efficacy remains underexplored in Adolescent and pediatric population. This systematic review and meta-analysis aims to assess the relative effectiveness of ECT, rTMS, and ketamine in treating TRD among adolescents.

METHODS

Following PRISMA guidelines, we systematically searched databases for studies of ECT, rTMS, or ketamine for treatment-resistant depression in youth ages 10-24. Three reviewers independently screened for inclusion based on predefined criteria. Included observational and randomized controlled trials reported depression symptoms with measures like HDRS and MADRS in youth treated with ECT, rTMS, or ketamine. Two reviewers extracted data on interventions, patients, and depression symptom outcomes. Chance-adjusted inter-reviewer agreement was calculated. For meta-analysis, we pooled standardized mean differences (SMDs) in depression scores using random effects models and assessed heterogeneity with I2 statistics.

RESULTS

Meta-analysis of 10 observational studies examined SMD in depression scores for treatment resistant depression patients treated with ECT, ketamine, or rTMS. Patients treated with ECT had a significantly lower SMD of 1.99 (95 % CI 0.92-3.05, p < 0.001) compared to baseline. Patients treated with ketamine also had a significantly lower SMD of 1.58 (95 % CI 1.04-2.12, p < 0.001). Patients treated with rTMS had the lowest SMD of 2.79 (95 % CI 0.79-4.80, p = 0.006). There was no significant difference between the three groups overall (p > 0.05). Comparative analysis between ECT and ketamine found no significant difference in SMD (p = 0.387). Comparison of ECT versus rTMS found a significant difference in SMD favoring rTMS (p = 0.004). Comparison of ketamine versus rTMS suggested a potential difference in SMD favoring rTMS (p = 0.058). In summary, rTMS resulted in significantly larger reductions in depression scores than ECT, and potentially larger reductions than ketamine.

CONCLUSIONS

This meta-analysis illustrates the ability of rTMS, ECT, and ketamine to improve depression in youth. rTMS resulted in the largest improvements, highlighting its potential as a first-line treatment for pediatric treatment-resistant depression given its favorable side effect profile compared to ECT. Further research directly comparing these modalities is needed.

A randomised, open-label, pragmatic pilot comparison of oral and intravenous ketamine in treatment-resistant depression

BACKGROUND

For depression, ketamine is more conveniently administered by oral than by intravenous (iv) routes. The relative antidepressant efficacy of oral vs iv ketamine is unknown.

OBJECTIVES

To assess the acute efficacy and the persistence of improvement with open-label oral versus iv ketamine in outpatients with treatment-resistant depression (TRD).

METHODS

Adults with TRD were randomized to oral (N=30) or IV (N=31) ketamine. Oral ketamine was dosed at 150 mg in 50 mL of water, sipped across 15 min. IV ketamine was dosed at 0.5 mg/kg, infused across 40 min. Ketamine sessions (total, 7) were administered on alternate days for 2 weeks. Ongoing antidepressant drugs were continued unchanged. Patients were assessed at baseline, day 14, and day 30. The primary outcome was the endpoint Hamilton Rating Scale for Depression score on day 14. Secondary outcomes were endpoint scores on the Montgomery-Asberg Depression Rating Scale, Beck Depression Inventory, and Clinical Global Impression-Severity of Illness and Improvement.

RESULTS

Overall dropout was lower with oral than with iv ketamine (26.7 % vs 54.8 %; P=0.03). The 2 groups did not differ in depression ratings and in response and remission rates on all instruments on both days 14 and 30. Adverse events such as headache (56.7 % vs 74.2 %) and drowsiness (0.0 % vs 22.6 %) were less common with oral ketamine.

CONCLUSION

In TRD outpatients treated in general hospitals, oral ketamine maybe better accepted and tolerated than iv ketamine. Conclusions about relative efficacy cannot be drawn because of the high dropout rate with iv ketamine.

"This is you teaching you:" Exploring providers' perspectives on experiential learning and enhancing patient safety and outcomes in ketamine-assisted therapy

OBJECTIVES

This study explores therapists' perspectives on experiential learning, competencies, and training in ketamine-assisted therapy (KAT), a form of psychedelic-assisted therapy (PAT). We aim to understand how therapists' personal psychedelic experiences influence their self-perceived competency and therapeutic relationships regarding KAT.

METHODS

Licensed therapists from Numinus Wellness clinics in Canada and the USA who were trained in KAT were invited to participate in the study. Participation included a 60-90-minute semi-structured interview conducted remotely via secure videoconferencing. The interviews focused on the professional and personal impacts of providing KAT, its mechanisms, and the role of therapists' personal psychedelic experiences in delivering KAT. Data analysis utilized Interpretative Phenomenological Analysis (IPA) and a mix of deductive and inductive coding with Nvivo software.

RESULTS

Eight therapists (62.5% female, 37.5% male) were interviewed. All had formal training in KAT, with many also trained in other forms of PAT. All respondents endorsed the value of personal psychedelic experience for deepening understanding of clients' experiences and strengthening the therapeutic alliance. They all also expressed a desire for formal experiential training in KAT, which they viewed as a missing element in their training. Additional themes identified included the importance of relational safety and the therapeutic container, KAT's impact on professional development, competency, and purpose, and navigating risks and challenges in KAT, particularly with complex trauma clients.

CONCLUSIONS

Our findings highlight the need for enhanced therapist training and evidence-based standardization of PAT programs that incorporate experiential learning. Such training has the potential to optimize safety and therapeutic outcomes.

Efficacy and safety of peri-partum Esketamine for prevention of post-partum depression in women undergoing caesarian section: A meta-analysis and systematic review of randomized controlled trials

Postpartum depression (PPD) is a psychiatric condition affecting women post-childbirth. Medication combined with psychotherapy, is the current protocol for its treatment. A meta-analysis was conducted using RevMan 5.4 to explore the efficacy and safety of peri-partum administration of esketamine for preventing PPD. After searching several databases to retrieve the relevant RCTs, seven were included in this analysis, with dichotomous data presented as risk ratio and continuous data as mean difference. The study found a lower incidence of PPD in the esketamine group compared to the control group (RR= 0.37), with significant difference in EPDS scores between the two groups (MD= -1.23) in the first week postpartum. The esketamine group reported a lower prevalence of PPD 4-6 weeks postpartum (RR= 0.48), and no significant difference in EPDS scores after 4 weeks postpartum (MD = -0.10). The esketamine group had a significantly higher incidence of hallucination (RR= 13.85). Other adverse effects, such as dizziness (RR= 4.09), nausea (RR= 0.88), vomiting (RR=0.74), headache (RR=1.52), nightmares (RR=1.22), pruritus (RR=0.29), and drowsiness (RR=1.57) did not show significant differences between the two groups. The study found that esketamine, with manageable side effects, reduces the prevalence of post-partum depression (PPD) after one week as well as after four to six weeks. However, the findings are limited by the limited number of available RCTs, and future research should determine the ideal dosage, the most effective method of administration and the long-term safety profile of esketamine so that it may be considered as an adjunct therapy or a potential sole treatment option.

Single administration of a psychedelic [(R)-DOI] influences coping strategies to an escapable social stress

Psychedelic compounds have potentially rapid, long-lasting anxiolytic, antidepressive and anti-inflammatory effects. We investigated whether the psychedelic compound (R)-2,5-dimethoxy-4-iodoamphetamine [(R)-DOI], a selective 5-HT2A receptor partial agonist, decreases stress-related behavior in male mice exposed to repeated social aggression. Additionally, we explored the likelihood that these behavioral changes are related to anti-inflammatory properties of [(R)-DOI]. Animals were subjected to the Stress Alternatives Model (SAM), an escapable social stress paradigm in which animals develop reactive coping strategies - remaining in the SAM arena (Stay) with a social aggressor, or dynamically initiated stress coping strategies that involve utilizing the escape holes (Escape) to avoid aggression. Mice expressing these behavioral phenotypes display behaviors like those in other social aggression models that separate animals into stress-vulnerable (as for Stay) or stress-resilient (as for Escape) groups, which have been shown to have distinct inflammatory responses to social stress. These results show that Stay animals have heightened cytokine gene expression, and both Stay and Escape mice exhibit plasma and neural concentrations of the inflammatory cytokine tumor necrosis factor-α (TNFα) compared to unstressed control mice. Additionally, these results suggest that a single administration of (R)-DOI to Stay animals in low doses, can increase stress coping strategies such as increasing attention to the escape route, promoting escape behavior, and reducing freezing during socially aggressive interaction in the SAM. Lower single doses of (R)-DOI, in addition to shifting behavior to suggest anxiolytic effects, also concomitantly reduce plasma and limbic brain levels of the inflammatory cytokine TNFα.

A meta-analysis of the effects of ketamine on suicidal ideation in depression patients

The treatment of suicidal ideation in patients with depression has been a major problem faced by psychiatric and emergency departments, and reasonable drug selection is particularly important. Ketamine has been shown to reduce suicidal ideation rapidly, but the strength of the effect is unclear and there is little evidence-based medical evidence to support this. We systematically searched all articles published on PubMed, Cochrane Library, Web of Science, CNKI and EMBASE. Stata 15 and R 4.1.3 were used for meta-analysis, and odds ratios were calculated in fixed effects or random effects models based on the heterogeneity test results. Our search resulted in 505 articles; we analyzed 14 studies, which included 1,380 participants. The 14 studies included 10 randomized controlled trial (RCT) studies and 4 single-arm studies. Our study suggests that, ketamine has a significant therapeutic effect on suicidal ideation throughout the treatment cycle. We performed network meta-analyses(NMA) and pairwise meta-analyses to compare the efficacy of ketamine in the reduction of suicidal ideation. There was a significant reduction in suicidal ideation within the first day after treatment (NMA ketamine day1 RR = 10.02, 95%CI = 4.24 to 23.68). In repeated treatment, the degree of recovery of suicidal ideation after the last dose was significantly greater than that after the first dose (RR = 0.56, 95%CI = 0.51 to 0.62). Recovery of suicidal ideation was also significantly better in the treatment end point than in the placebo group at the same time point (NMA ketamine day26 RR = 4.29, 95%CI = 1.41 to 13.08). This is the first network meta-analysis to demonstrate the role of ketamine in the alleviation of suicidal ideation. Our network meta-analysis also compared the effects of different drugs at different time points, which was not done in previous studies. This is of great reference significance for future drug research andrational drug use.

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.

Efficacy and safety of ketamine and esketamine for unipolar and bipolar depression: an overview of systematic reviews with meta-analysis

BACKGROUND

Unipolar and bipolar depression present treatment challenges, with patients sometimes showing limited or no response to standard medications. Ketamine and its enantiomer, esketamine, offer promising alternative treatments that can quickly relieve suicidal thoughts. This Overview of Reviews (OoR) analyzed and synthesized systematic reviews (SRs) with meta-analysis on randomized clinical trials (RCTs) involving ketamine in various formulations (intravenous, intramuscular, intranasal, subcutaneous) for patients with unipolar or bipolar depression. We evaluated the efficacy and safety of ketamine and esketamine in treating major depressive episodes across various forms, including unipolar, bipolar, treatment-resistant, and non-resistant depression, in patient populations with and without suicidal ideation, aiming to comprehensively assess their therapeutic potential and safety profile.

METHODS

Following PRIOR guidelines, this OoR's protocol was registered on Implasy (ID:202150049). Searches in PubMed, Scopus, Cochrane Library, and Epistemonikos focused on English-language meta-analyses of RCTs of ketamine or esketamine, as monotherapy or add-on, evaluating outcomes like suicide risk, depressive symptoms, relapse, response rates, and side effects. We included studies involving both suicidal and non-suicidal patients; all routes and formulations of administration (intravenous, intramuscular, intranasal) were considered, as well as all available comparisons with control interventions. We excluded meta-analysis in which the intervention was used as anesthesia for electroconvulsive therapy or with a randomized ascending dose design. The selection, data extraction, and quality assessment of studies were carried out by pairs of reviewers in a blinded manner. Data on efficacy, acceptability, and tolerability were extracted.

RESULTS

Our analysis included 26 SRs and 44 RCTs, with 3,316 subjects. The intervention is effective and well-tolerated, although the quality of the included SRs and original studies is poor, resulting in low certainty of evidence.

LIMITATIONS

This study is limited by poor-quality SRs and original studies, resulting in low certainty of the evidence. Additionally, insufficient available data prevents differentiation between the effects of ketamine and esketamine in unipolar and bipolar depression.

CONCLUSION

While ketamine and esketamine show promising therapeutic potential, the current evidence suffers from low study quality. Enhanced methodological rigor in future research will allow for a more informed application of these interventions within the treatment guidelines for unipolar and bipolar depression.

SYSTEMATIC REVIEW REGISTRATION

[https://inplasy.com/inplasy-2021-5-0049/], identifier (INPLASY202150049).

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.

Mechanism of Antidepressant Action of (2R,6R)-6-Hydroxynorketamine (HNK) and Its Compounds: Insights from Proteomic Analysis

The effects of HNK, I5, and I6 on the expression of protein in hippocampus of depressed mice were studied by isobaric tags for relative and absolute quantitation (iTRAQ) to explore the mechanism of their antidepressant action. HNK, I5, and I6 were administered intragastric administration once a day in the morning for 7 days. The drug was subsequently discontinued for 7 days (without any treatment). On the 15th day, mice in each group were given the drug (1.0, 10.0, 30.0 mg/kg) intragastric stimulation and mouse hippocampal tissues were taken to perform iTRAQ to identify differentially expressed proteins, and bioinformatics was used to analyze the functional enrichment of the differentially expressed proteins. Compared with Ctr group, the number of differentially expressed proteins in HNK, I5, and I6 treatment groups was 158, 88, and 105, respectively. The three groups shared 29 differentially expressed proteins. In addition, compared with HNK group, the number of differentially expressed proteins in I5 and I6 groups was 201 and 203, respectively. A total of 47 and 56 differentially expressed proteins were co-expressed in I5 and I6 groups. Bioinformatics analysis showed that these differentially expressed proteins mainly had the functions of binding, biocatalysis, and transport, and mainly participated in cellular process, biological regulation process, biological metabolism process, and stress reaction process. GO and KEGG pathway analysis found that these differentially expressed proteins were involved long-term potentiation, G13 pathway, platelet activation pathway, and MAPK signaling pathway. HNK, I5, and I6 antidepressants are closely related to sudden stress sensitivity, stress resistance, neurotransmitter, and metabolic pathways. This study provides a scientific basis to further elucidate the mechanism and clinical application of HNK, I5, and I6 antidepressants.

[Ketamine in antidepressant treatment: a revolution?]

Thirty percent of depressed patients are treatment resistant (TRD) suggesting the need of new therapeutic strategy. Recently, it has been shown that ketamine, an anesthetic agent with dissociative effects, has potent and rapid antidepressant properties. Ketamine is a ionotropic glutamatergic NMDA antagonist that inhibits gabaergic neurons. Its antidepressant effect peaks at 24 h post-treatment. Several meta-analyses of placebo randomized clinical trials emphasized its efficacy. More recently, a meta-analysis showed its efficiency in real-world population of TRD patients. Although there is no clear biological or clinical predictors of response or remission to ketamine, patients with high level of resistance were found to remit less often. Restoring both the optimism bias and the asymmetry in belief updating mediates the antidepressant ketamine's effect. Consistent with predictive bayesian model and terror management theory, this suggests that dissociation induced by ketamine may contribute to its clinical antidepressant action. Although increasing access to ketamine and esketamine is welcome, legitimate concerns have been raised with respect to long-term safety and abuse risk.

Storm on predictive brain: A neurocomputational account of ketamine antidepressant effect

For the past decade, ketamine, an N-methyl-D-aspartate receptor (NMDAr) antagonist, has been considered a promising treatment for major depressive disorder (MDD). Unlike the delayed effect of monoaminergic treatment, ketamine may produce fast-acting antidepressant effects hours after a single administration at subanesthetic dose. Along with these antidepressant effects, it may also induce transient dissociative (disturbing of the sense of self and reality) symptoms during acute administration which resolve within hours. To understand ketamine's rapid-acting antidepressant effect, several biological hypotheses have been explored, but despite these promising avenues, there is a lack of model to understand the timeframe of antidepressant and dissociative effects of ketamine. In this article, we propose a neurocomputational account of ketamine's antidepressant and dissociative effects based on the Predictive Processing (PP) theory, a framework for cognitive and sensory processing. PP theory suggests that the brain produces top-down predictions to process incoming sensory signals, and generates bottom-up prediction errors (PEs) which are then used to update predictions. This iterative dynamic neural process would relies on N-methyl-D-aspartate (NMDAr) and α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic receptors (AMPAr), two major component of the glutamatergic signaling. Furthermore, it has been suggested that MDD is characterized by over-rigid predictions which cannot be updated by the PEs, leading to miscalibration of hierarchical inference and self-reinforcing negative feedback loops. Based on former empirical studies using behavioral paradigms, neurophysiological recordings, and computational modeling, we suggest that ketamine impairs top-down predictions by blocking NMDA receptors, and enhances presynaptic glutamate release and PEs, producing transient dissociative symptoms and fast-acting antidepressant effect in hours following acute administration. Moreover, we present data showing that ketamine may enhance a delayed neural plasticity pathways through AMPAr potentiation, triggering a prolonged antidepressant effect up to seven days for unique administration. Taken together, the two sides of antidepressant effects with distinct timeframe could constitute the keystone of antidepressant properties of ketamine. These PP disturbances may also participate to a ketamine-induced time window of mental flexibility, which can be used to improve the psychotherapeutic process. Finally, these proposals could be used as a theoretical framework for future research into fast-acting antidepressants, and combination with existing antidepressant and psychotherapy.

Change in Negative Affective Bias following a Single Ketamine Treatment for Treatment-Resistant Depression

Ketamine has recently emerged as a highly effective new treatment for people with treatment-resistant depression with rapid antidepressant effects. However, these effects are often short lasting, and the potential cognitive mechanisms underlying the therapeutic effects, such as effects on emotional processing bias, remain poorly understood. In the present study, we explored potential changes in emotional and cognitive processing following a single treatment of subcutaneous ketamine in a randomised double-blind controlled study with an active control. Participants with treatment-resistant major depressive disorder (MDD) were recruited from a single site from the Ketamine for Adult Depression Study (KADS Trial) and were randomly assigned to receive racemic ketamine hydrochloride (n = 10) or midazolam hydrochloride (n = 11) in a 1 : 1 ratio. A healthy control sample (n = 23) was recruited to attend a single experimental session without any treatment. All MDD participants completed mood ratings and cognitive assessments prior to and one day after a single randomised treatment. The results showed no significant differences in performance changes after treatment across the majority of emotion-related (i.e., Emotional Stroop Task, Affective Go/No-Go Task) and cognitive (Ruff 2 and 7 Selective Attention Test, Controlled Word Association Test) outcome measures. Participants who received ketamine showed a significant improvement in a negative processing bias test (i.e., The Scrambled Sentence Task; Cohen's d = .67, p = .016), which was not significantly associated with improvement in psychological symptoms (r = -.662, p = .074). The results from this exploratory study suggest that a single ketamine treatment may modulate negative affective bias. Limitations to this study included the small sample size and lack of follow-up. Future larger trials are required to confirm this finding.

Ketamine for the treatment of major depression: a systematic review and meta-analysis

Background

Intranasal esketamine has received regulatory approvals for the treatment of depression. Recently a large trial of repeated dose racemic ketamine also demonstrated efficacy in severe depression. However, uncertainties remain regarding comparative efficacy, dosage, and the time course of response.

Methods

In this systematic review and meta-analysis, we searched Embase, Medline, Pubmed, PsycINFO, and CENTRAL up to April 13, 2023, for randomised controlled trials (RCTs) investigating ketamine for depression. Two investigators independently assessed study eligibility and risk of bias and extracted the data on depression severity scores, response and remission rates, and all-cause dropouts. Multivariable mixed-effects meta-regressions incorporated drug formulation (racemic (Rac) or esketamine (Esket)) and dose (Low or High) as covariates. Treatment effects were assessed: immediately following the first dose, during further repeated dosing, and follow-up after the final dose of a treatment course. This study is registered with PROSPERO (CRD42021221157).

Findings

The systematic review identified 687 articles, of which 49 RCTs were eligible for analysis, comprising 3299 participants. Standardised mean differences (95% confidence intervals) immediately following the first/single treatment were moderate-high for all conditions (Rac-High: -0.73, -0.91 to -0.56; Esket-High: -0.48, -0.75 to -0.20; Rac-Low: -0.33, -0.54 to -0.12; Esket-Low: -0.55, -0.87 to -0.24). Ongoing effects during repeated dosing were significantly greater than the control for Rac-High (-0.61; -1.02 to -0.20) and Rac-Low (-0.55, -1.09 to -0.00), but not Esket-Low (-0.15, -0.49 to 0.19) or Esket-High (-0.22, -0.54 to 0.10). At follow-up effects remained significant for racemic ketamine (-0.65; -1.23 to -0.07) but not esketamine (-0.33; -0.96 to 0.31). All-cause dropout was similar between experiment and control conditions for both formulations combined (Odds Ratio = 1.18, 0.85-1.64). Overall heterogeneity varied from 5.7% to 87.6.

Interpretation

Our findings suggested that effect sizes for depression severity, as well as response and remission rates, were numerically greater for racemic ketamine than esketamine. Higher doses were more effective than low doses. Differences were evident in initial effects, ongoing treatment, and lasting effects after the final dose.

Funding

None.

Mental Health: Pandemics, Epidemics and Tau Protein

Background

It is well established that a wide range of psychological disorders are influenced by the way people live, with lifestyle-related factors playing a substantial role. During the past decade, the effects of major disasters on mental health have drawn a lot of attention.

Aim

In this review, we compare clinical studies reporting a link between COVID-19 and other pandemics and mental health. Importantly, we also shed light on Tau protein and neurotransmitters as neurobiological factors that might explain this link.

Methods

A thorough PubMed search was done to gather and summarize published data on the COVID-19 pandemic's effect on mental health. Additionally, these studies were compared to previous research published on PubMed, triggering other pandemic and epidemic impacts on mental health.

Results

The COVID-19 epidemic has had the biggest impact on raising awareness about mental health. Moreover, the past century has seen an increase in the frequency of disease outbreaks like MERS-CoV, Ebola, and Influenza, which all had an impact on mental health. However, the exact role of these epidemics on mental health and brain functions is poorly understood.

Conclusion

Future research on the underlying pathways may yield essential information for the treatment and prevention of prospective mental diseases in light of the ongoing decline in mental health during the past 10 years.

Taiwan consensus on biological treatment of bipolar disorder during the acute, maintenance, and mixed phases: The 2022 update

BACKGROUND

Bipolar disorder is a mood dysregulation characterized by recurrent symptoms and episodes of mania, hypomania, depression, and mixed mood. The complexity of treating patients with bipolar disorder prompted the Taiwanese Society of Biological Psychiatry and Neuropsychopharmacology (TSBPN) to publish the first Taiwan consensus on pharmacological treatment of bipolar disorders in 2012. This paper presents the updated consensus, with changes in diagnostic criteria (i.e., mixed features) and emerging pharmacological evidence published up to April 2022.

METHODS

Our working group systemically reviewed the clinical research evidence and international guidelines and determined the levels of evidence for each pharmacological treatment on the basis of the most recent World Federation of Societies of Biological Psychiatry grading system. Four clinical-specific issues were proposed. The current TSBPN Bipolar Taskforce then discussed research evidence and clinical experience related to each treatment option in terms of efficacy and acceptability and then appraised final recommendation grades through anonymous voting.

RESULTS

In the updated consensus, we include the pharmacological recommendations for bipolar disorder with mixed features considering its high prevalence, the severe clinical prognosis, and the absence of approved medications. Cariprazine, lurasidone, repetitive transcranial magnetic stimulation, and ketamine are incorporated as treatment options. In the maintenance phase, the application of long-acting injectable antipsychotics is emphasized, and the hazards of using antidepressants and conventional antipsychotics are proposed.

CONCLUSIONS

This updated Taiwan consensus on pharmacological treatment for bipolar disorder provides concise evidence-based and empirical recommendations for clinical psychiatric practice. It may facilitate treatment outcome improvement in patients with bipolar disorder.

Role of group II metabotropic glutamate receptors in ketamine's antidepressant actions

Major Depressive Disorder (MDD) is a serious neuropsychiatric disorder afflicting around 16-17 % of the global population and is accompanied by recurrent episodes of low mood, hopelessness and suicidal thoughts. Current pharmacological interventions take several weeks to even months for an improvement in depressive symptoms to emerge, with a significant percentage of individuals not responding to these medications at all, thus highlighting the need for rapid and effective next-generation treatments for MDD. Pre-clinical studies in animals have demonstrated that antagonists of the metabotropic glutamate receptor subtype 2/3 (mGlu_2/3 receptor) exert rapid antidepressant-like effects, comparable to the actions of ketamine. Therefore, it is possible that mGlu₂ or mGlu₃ receptors to have a regulatory role on the unique antidepressant properties of ketamine, or that convergent intracellular mechanisms exist between mGlu_2/3 receptor signaling and ketamine's effects. Here, we provide a comprehensive and critical evaluation of the literature on these convergent processes underlying the antidepressant action of mGlu_2/3 receptor inhibitors and ketamine. Importantly, combining sub-threshold doses of mGlu_2/3 receptor inhibitors with sub-antidepressant ketamine doses induce synergistic antidepressant-relevant behavioral effects. We review the evidence supporting these combinatorial effects since sub-effective dosages of mGlu_2/3 receptor antagonists and ketamine could reduce the risk for the emergence of significant adverse events compared with taking normal dosages. Overall, deconvolution of ketamine's pharmacological targets will give critical insights to influence the development of next-generation antidepressant treatments with rapid actions.

The long noncoding RNA FEDORA is a cell type- and sex-specific regulator of depression

Women suffer from depression at twice the rate of men, but the underlying molecular mechanisms are poorly understood. Here, we identify marked baseline sex differences in the expression of long noncoding RNAs (lncRNAs), a class of regulatory transcripts, in human postmortem brain tissue that are profoundly lost in depression. One such human lncRNA, RP11-298D21.1 (which we termed FEDORA), is enriched in oligodendrocytes and neurons and up-regulated in the prefrontal cortex (PFC) of depressed females only. We found that virally expressing FEDORA selectively either in neurons or in oligodendrocytes of PFC promoted depression-like behavioral abnormalities in female mice only, changes associated with cell type-specific regulation of synaptic properties, myelin thickness, and gene expression. We also found that blood FEDORA levels have diagnostic implications for depressed women and are associated with clinical response to ketamine. These findings demonstrate the important role played by lncRNAs, and FEDORA in particular, in shaping the sex-specific landscape of the brain and contributing to sex differences in depression.

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.

Efficacy and safety of racemic ketamine and esketamine for depression: a systematic review and meta-analysis

BACKGROUND

Racemic ketamine and esketamine have demonstrated rapid antidepressant effects. We aimed to review the efficacy and safety of racemic and esketamine for depression.

RESEARCH DESIGN AND METHODS

We conducted a PRISMA-guided review for relevant randomized controlled trials of racemic or esketamine for unipolar or bipolar major depression from database inception through 2021. We conducted random-effects meta-analyses using pooled rate ratios (RRs) and Cohen's standardized mean differences (d) with their 95% confidence intervals (CI).

RESULTS

We found 36 studies (2903 participants, 57% female, 45.1 +/- 7.0 years). Nine trials used esketamine, while the rest used racemic ketamine. The overall study quality was high. Treatment with any form of ketamine was associated with improved response (RR=2.14; 95% CI, 1.72-2.66; I2=65%), remission (RR=1.64; 95% CI, 1.33-2.02; I2=39%), and depression severity (d=-0.63; 95% CI, -0.80 to -0.45; I2=78%) against placebo. Overall, there was no association between treatment with any form of ketamine and retention in treatment (RR=1.00; 95% CI, 0.99-1.01; I2<1%), dropouts due to adverse events (RR=1.56; 95% CI, 1.00-2.45; I2<1%), or the overall number of adverse events reported per participant (OR=2.14; 95% CI, 0.82-5.60; I2=62%) against placebo.

CONCLUSIONS

Ketamine and esketamine are effective, safe, and acceptable treatments for individuals living with depression.

Ketamine for Bipolar Depression: Biochemical, Psychotherapeutic, and Psychedelic Approaches

Bipolar disorder (type 1) is a serious and chronic psychiatric illness that can be difficult to treat. Many bipolar patients have refractory depressive episodes. Racemic ketamine, a glutamate modulator with prominent dissociate and psychedelic properties, has been demonstrated to have rapid acting antidepressant and anti-obsessional effects which may be useful for treating the symptoms of bipolar depression. Most of the existing research literature on unipolar and bipolar depression has looked at racemic ketamine in the sub-psychedelic dose range given by infusion as a stand-alone treatment (without concurrent psychotherapy). This article expands on the existing research by articulating three different paradigms for ketamine treatment: biochemical, psychotherapeutic, and psychedelic. The authors use composite clinical vignettes to illustrate different ways of working with ketamine to treat bipolar depression, and discuss a variety of clinical considerations for using ketamine with this population, including route, dose, frequency, chemical mitigators, and adverse events. Note that the conceptual paradigms could be applied to any ketamine treatment, with broad applicability beyond bipolar treatment.

Ketamine use disorder: preclinical, clinical, and neuroimaging evidence to support proposed mechanisms of actions

Ketamine, a noncompetitive NMDA receptor antagonist, has been exclusively used as an anesthetic in medicine and has led to new insights into the pathophysiology of neuropsychiatric disorders. Clinical studies have shown that low subanesthetic doses of ketamine produce antidepressant effects for individuals with depression. However, its use as a treatment for psychiatric disorders has been limited due to its reinforcing effects and high potential for diversion and misuse. Preclinical studies have focused on understanding the molecular mechanisms underlying ketamine's antidepressant effects, but a precise mechanism had yet to be elucidated. Here we review different hypotheses for ketamine's mechanism of action including the direct inhibition and disinhibition of NMDA receptors, AMPAR activation, and heightened activation of monoaminergic systems. The proposed mechanisms are not mutually exclusive, and their combined influence may exert the observed structural and functional neural impairments. Long term use of ketamine induces brain structural, functional impairments, and neurodevelopmental effects in both rodents and humans. Its misuse has increased rapidly in the past 20 years and is one of the most common addictive drugs used in Asia. The proposed mechanisms of action and supporting neuroimaging data allow for the development of tools to identify 'biotypes' of ketamine use disorder (KUD) using machine learning approaches, which could inform intervention and treatment.

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.

Psychedelics for the treatment of depression, anxiety, and existential distress in patients with a terminal illness: a systematic review

BACKGROUND

Terminally ill patients may experience existential distress, depression, or anxiety, limiting quality of life in the final stage. Existing psychotherapeutic or pharmacological interventions have (time) limited efficacy. Psychedelic treatment may be a safe and effective alternative treatment option.

AIM

Systematically review studies on psychedelic treatment with and without psychotherapy for existential distress, depression, and anxiety in terminally ill patients.

METHODS

Medline, PsycINFO, and Embase were searched for original-data studies on the treatment of depression, anxiety, and existential distress with classical or a-typical psychedelics in patients with a terminal illness, using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

A total of 1850 records were screened, and 33 articles were included in this review: 14 studies on classical psychedelics (DPT, LSD, and psilocybin) and 19 studies on atypical psychedelics (MDMA and ketamine). Results of early pre-post studies are promising but have serious methodological flaws. Recent (controlled) trials with LSD, psilocybin, ketamine, and MDMA are of higher methodological quality and indicate positive effects on existential and spiritual well-being, quality of life, acceptance, and reduction of anxiety and depression with few adverse and no serious adverse effects.

CONCLUSIONS

Both classical and a-typical psychedelics are promising treatment options in patients with terminal illness. To draw final conclusions on effectiveness and safety of psychedelics, we need larger high-quality studies for classical psychedelics and MDMA. Ketamine studies should pay more attention to existential dimensions of well-being and the psychotherapeutic context of the treatment.

Ketamine for the treatment of mental health and substance use disorders: comprehensive systematic review

BACKGROUND

In the past two decades, subanaesthetic doses of ketamine have been demonstrated to have rapid and sustained antidepressant effects, and accumulating research has demonstrated ketamine's therapeutic effects for a range of psychiatric conditions.

AIMS

In light of these findings surrounding ketamine's psychotherapeutic potential, we systematically review the extant evidence on ketamine's effects in treating mental health disorders.

METHOD

The systematic review protocol was registered in PROSPERO (identifier CRD42019130636). Human studies investigating the therapeutic effects of ketamine in the treatment of mental health disorders were included. Because of the extensive research in depression, bipolar disorder and suicidal ideation, only systematic reviews and meta-analyses were included. We searched Medline and PsycINFO on 21 October 2020. Risk-of-bias analysis was assessed with the Cochrane Risk of Bias tools and A Measurement Tool to Assess Systematic Reviews (AMSTAR) Checklist.

RESULTS

We included 83 published reports in the final review: 33 systematic reviews, 29 randomised controlled trials, two randomised trials without placebo, three non-randomised trials with controls, six open-label trials and ten retrospective reviews. The results were presented via narrative synthesis.

CONCLUSIONS

Systematic reviews and meta-analyses provide support for robust, rapid and transient antidepressant and anti-suicidal effects of ketamine. Evidence for other indications is less robust, but suggests similarly positive and short-lived effects. The conclusions should be interpreted with caution because of the high risk of bias of included studies. Optimal dosing, modes of administration and the most effective forms of adjunctive psychotherapeutic support should be examined further.

The probability of response after each subcutaneous injection of esketamine in treatment-resistant depression

INTRODUCTION

The administration of multiple esketamine doses has shown efficacy for unipolar and bipolar treatment-resistant depression (TRD). Nevertheless, the probability of responding or not after each dose in the real-world remains unknown. This study aimed to estimate it throughout four doses of esketamine, administrated via subcutaneous (SC).

MATERIAL AND METHODS

We conducted a retrospective analysis of a case series of 70 patients with TRD who received treatment from the esketamine assistance program at Federal University of Sao Paulo, between April 2017 and December 2018. The SC injections were administrated weekly at a dose of 0.5-1.0mg/kg, in conjunction with patients' psychotropic drugs. Response was defined as a decrease of at least 50% in the Montgomery-Åsberg Depression Rating Scale between baseline and 24h after dose. We used hidden Markov modeling in order to estimate de probability of response after each esketamine injection.

RESULTS

The probability of a patient that was a "non-responder" to become a "responder" following a SC injection of esketamine was 17.30% and the probability that this patient remains a "non-responder" was 82.70%. The probability of a patient that was a "responder" to remain as a "responder" was 95%.

CONCLUSIONS

Patients with TRD who had not responded after the first dose of esketamine, still had a chance of responding after the subsequent dose administrated via SC.

[Ketamine Augmented Psychotherapy (KAP) in mood disorder: User guide]

Ketamine, a non-competitive NMDA receptor antagonist, is used as a fast-acting antidepressant therapy in depressive disorders. This treatment provokes dissociative effects associating derealization and depersonalization, and a synaptogenic signaling cascade promoting brain plasticity. Despite several preliminary studies suggesting the usefulness of its combination with psychotherapy, administration of ketamine isn't generally combined with per- and post-infusion psychotherapy protocols in its clinical antidepressant use. However, the phenomenology of psychodysleptic experiences and the synaptogenic effect could potentiate cognitive and behavioral therapies (CBT). In this article, we purpose a practical protocol to Ketamine Augmented Psychotherapy (KAP) synthesizing contemporary data from the literature and our clinical experience. We detail proposals for clinical practice, and propose four important steps for the use of a psychodysleptic molecule for antidepressant purposes: preparation, administration, integration, and prolongation. Finally, we discuss the limits and prospects of this combination in the management of mood disorders.

Novel rapid-acting glutamatergic modulators: Targeting the synaptic plasticity in depression

Major depressive disorder (MDD) is severely prevalent, and conventional monoaminergic antidepressants gradually exhibit low therapeutic efficiency, especially for patients with treatment-resistant depression. A neuroplasticity hypothesis is an emerging advancement in the mechanism of depression, mainly expressed in the glutamate system, e.g., glutamate receptors and signaling. Dysfunctional glutamatergic neurotransmission is currently considered to be closely associated with the pathophysiology of MDD. Biological function, pharmacological action, and signal attributes in the glutamate system both regulate the neural process. Specific functional subunits could be therapeutic targets to explore the novel glutamatergic modulators, which have fast-acting, and relatively sustained antidepressant effects. Here, the present review summarizes the pathophysiology of MDD found in the glutamate system, exploring the role of glutamate receptors and their downstream effects. These convergent mechanisms have prompted the development of other modulators targeting on glutamate system, including N-methyl-d-aspartate receptor antagonists, selective GluN2B-specific antagonists, glycine binding site agents, and regulators of metabotropic glutamate receptors. Relevant researches underly the putative mechanisms of these drugs, which reverse the damage of depression by regulating glutamatergic neurotransmission. It also provides further insight into the mechanism of depression and exploring potential targets for novel agent development.

Efficacy of ketamine for major depressive episodes at 2, 4, and 6-weeks post-treatment: A meta-analysis

RATIONALE

Major depressive episodes are severe mood episodes which occur both in major depressive disorder and bipolar I and II disorder. Major depressive episodes are characterized by debilitating symptoms that often persist and interfere with typical daily functioning. Various treatments exist for major depressive episodes; however, most primary pharmacologic treatments may take weeks to months to provide relief from depressive symptoms. Ketamine is a demonstrated treatment for major depressive episodes, as relief from depressive symptoms can occur rapidly following treatment.

OBJECTIVES

Prior meta-analyses have been conducted to analyze the effectiveness of ketamine for the treatment of major depressive episodes, but at the time of this writing, no meta-analysis had been conducted to observe ketamine treatment efficacy beyond 2 weeks.

METHODS

The present meta-analysis evaluated the efficacy of ketamine for the treatment of major depressive episodes; observations of depressive episode severity were analyzed at 2, 4, and 6-weeks post-treatment.

RESULTS

The present meta-analysis observed large effects at 2 weeks (g = -1.28), 4 weeks, (g = -1.28), and 6 weeks (g = -1.36) post-treatment.

CONCLUSIONS

The results from the present meta-analysis indicate that ketamine can be an effective pharmacologic intervention for major depressive episodes, with treatment effects lasting up to 6 weeks post-ketamine administration, which has many positive implications for treatment.

Intranasal Ketamine for Depression in Adults: A Systematic Review and Meta-Analysis of Randomized, Double-Blind, Placebo-Controlled Trials

Background

There is growing interest in glutamatergic agents as a treatment for depression, especially intranasal ketamine, which has become a hot topic in recent years. We aim to assess the efficacy and safety of intranasal ketamine in the treatment of major depressive disorder (MDD), especially treatment-resistant depression (TRD).

Methods

We searched Medline, EMBASE, and the Cochrane Library until April 1, 2020 to identify double-blind, randomized controlled trials with allocation concealment evaluating intranasal ketamine in major depressive episodes. Clinical remission, response, and depressive symptoms were extracted by two independent raters. The outcome measures were Montgomery–Asberg Depression Rating Scale (MADRS) score improved from baseline, clinical response and remission, dissociative symptoms, and common adverse events. The analyses employed a random-effects model.

Results

Data were synthesized from five randomized controlled trials (RCTs) employing an intranasal esketamine and one RCT employing intranasal ketamine, representing 840 subjects in parallel arms, and 18 subjects in cross-over designs (n = 858 with MDD, n = 792 with TRD). The weighted mean difference of MADRS score was observed to decrease by 6.16 (95% CI 4.44–7.88) in 2–4 h, 9.96 (95% CI 8.97–10.95) in 24 h, and 4.09 (95% CI 2.18–6.00) in 28 day. The pooled relative risk (RR) was 3.55 (95% CI 1.5–8.38, z = 2.89, and p < 0.001) for clinical remission and 3.22 (95% CI 1.85–5.61, z = 4.14, and p < 0.001) for clinical response at 24 h, while the pooled RR was 1.7 (95% CI 1.28–2.24, z = 3.72, and p < 0.001) for clinical remission and 1.48 (95% CI 1.17–1.86, z = 3.28, and p < 0.001) for clinical response at 28 day. Intranasal ketamine was associated with the occurrence of transient dissociative symptoms and common adverse events, but no persistent psychoses or affective switches.

Conclusion

Our meta-analysis suggests that repeated intranasal ketamine conducted a fast-onset antidepression effect in unipolar depression, while the mild and transient adverse effects were acceptable.

Systematic Review Registration

PROSPERO, CRD42020196856.

Analgesic and Antidepressant Effects of the Clinical Glutamate Modulators Acetyl-L-Carnitine and Ketamine

Pain and depression are leading causes of disability and of profound social and economic burden. Their impact is aggravated by their chronicity and comorbidity and the insufficient efficacy of current treatments. Morphological and functional metabolism studies link chronic pain and depressive disorders to dysfunctional neuroplastic changes in fronto-limbic brain regions that control emotional responses to painful injuries and stressful events. Glutamate modulators are emerging new therapies targeting dysfunctional brain areas implicated in the generation and maintenance of chronic pain and depression. Here, we report the effects of two clinically approved glutamate modulators: acetyl-L-carnitine (ALCAR) and S, R(±)ketamine (KET). ALCAR is a natural neurotrophic compound currently marketed for the treatment of neuropathies. KET is the prototypical non-competitive antagonist at N-methyl-D-aspartate glutamate receptors and a clinically approved anesthetic. Although they differ in pharmacological profiles, ALCAR and KET both modulate aminergic and glutamatergic neurotransmissions and pain and mood. We assessed in rats the effects of ALCAR and KET on cerebral metabolic rates for glucose (rCMRglc) and assessed clinically the effects of ALCAR in chronic pain and of KET in post-operative pain. ALCAR and KET increased rCMRglc at similar degrees in prefrontal, somatosensory, and cingulate cortices, and KET increased rCMRglc at a different, much larger, degree in limbic and dopaminergic areas. While rCMRglc increases in prefrontal cortical areas have been associated with analgesic and antidepressant effects of ALCAR and KET, the marked metabolic increases KET induces in limbic and dopaminergic areas have been related to its psychotomimetic and abuse properties. In patients with chronic neuropathic pain, ALCAR (1,000 mg/day) yielded to a fast (2 weeks) improvement of mood and then of pain and quality of life. In day-surgery patients, KET improved dischargeability and satisfaction. In obese patients undergoing bariatric surgery, a single, low dose of KET (0.5 mg/kg) at induction of anesthesia determined a very fast (hours) amelioration of post-operative depression and pain and an opioid-sparing effect. These findings indicate that ALCAR and KET, two non-selective glutamate modulators, still offer viable therapeutic options in comorbid pain and depression.

Novel Glutamatergic Modulators for the Treatment of Mood Disorders: Current Status

The efficacy of standard antidepressants is limited for many patients with mood disorders such as major depressive disorder (MDD) and bipolar depression, underscoring the urgent need to develop novel therapeutics. Both clinical and preclinical studies have implicated glutamatergic system dysfunction in the pathophysiology of mood disorders. In particular, rapid reductions in depressive symptoms have been observed in response to subanesthetic doses of the glutamatergic modulator racemic (R,S)-ketamine in individuals with mood disorders. These results have prompted investigation into other glutamatergic modulators for depression, both as monotherapy and adjunctively. Several glutamate receptor-modulating agents have been tested in proof-of-concept studies for mood disorders. This manuscript gives a brief overview of the glutamate system and its relevance to rapid antidepressant response and discusses the existing clinical evidence for glutamate receptor-modulating agents, including (1) broad glutamatergic modulators ((R,S)-ketamine, esketamine, (R)-ketamine, (2R,6R)-hydroxynorketamine [HNK], dextromethorphan, Nuedexta [a combination of dextromethorphan and quinidine], deudextromethorphan [AVP-786], axsome [AXS-05], dextromethadone [REL-1017], nitrous oxide, AZD6765, CLE100, AGN-241751); (2) glycine site modulators (D-cycloserine [DCS], NRX-101, rapastinel [GLYX-13], apimostinel [NRX-1074], sarcosine, 4-chlorokynurenine [4-Cl-KYN/AV-101]); (3) subunit (NR2B)-specific N-methyl-D-aspartate (NMDA) receptor antagonists (eliprodil [EVT-101], traxoprodil [CP-101,606], rislenemdaz [MK-0657/CERC-301]); (4) metabotropic glutamate receptor (mGluR) modulators (basimglurant, AZD2066, RG1578, TS-161); and (5) mammalian target of rapamycin complex 1 (mTORC1) activators (NV-5138). Many of these agents are still in the preliminary stages of development. Furthermore, to date, most have demonstrated relatively modest effects compared with (R,S)-ketamine and esketamine, though some have shown more favorable characteristics. Of these novel agents, the most promising, and the ones for which the most evidence exists, appear to be those targeting ionotropic glutamate receptors.

[Efficacy of psychedelics in psychiatry, a systematic review of the literature]

OBJECTIVES

Psychedelics are powerful psychoactive substances. Natural psychedelics have been used for millennia by human civilizations, in particular in Latin America, while synthetic psychedelics were discovered in the 50s, giving rise to a lot of research before they were prohibited. More recently, their therapeutic properties have been studied especially to help patients with psychiatric conditions, psychological distress or substance use disorders. This article is a systematic review of the literature which aims to provide an overview of all studies that assessed the efficacy of psychedelics, i.e. psilocybin, ayahuasca and lysergic acid diethylamide (LSD), on psychiatric diseases and addictions.

METHODS

We conducted this literature review following the PRISMA recommendations. MEDLINE, PsycInfo, Web of Science and Scopus were searched from January 1990 to May 2020 with the following keywords "(ayahuasca OR psilocybin OR lysergic acid diethylamide) AND (depression OR anxiety OR major depressive disorder OR bipolar disorder OR anxiety disorder OR substance use disorder OR dependence)".

RESULTS

Twenty-five articles met the inclusion criteria. Five articles studied psychedelic efficacy in the treatment of life-threatening diseases related to anxiety and depression: four were randomized controlled crossover trials (three with psilocybin for a total of 92 patients, and one with LSD, n=12), and one was a long-term follow-up study. Eleven articles explored the efficacy of psychedelics in the treatment of major depressive episodes: two were open-labeled trials (one with ayahuasca, n=17, one with psilocybin, n=20), one was a randomized controlled trial using ayahuasca against placebo (n=29), and the others were long-term follow-up studies or assessed more precise dimensions of the depressive disorder, such as suicidality, emotion processing or personality traits. Eight articles studied the efficacy of psychedelics in the treatment of addictions: two were open-labeled studies using psilocybin (one in alcohol use disorder, n=10, and one in tobacco use disorder, n=15), and the others were long-term follow-up studies or retrospective observational descriptive studies on alcohol, tobacco, opioids, cannabis, and psychostimulants. One study explored the efficacy of psilocybin in obsessional-compulsive disorder (n=9). Overall, these studies found a quick and important response after psychedelic administration that lasted for several months, even after a single dose. However most of these studies were descriptive or open-label studies conducted on small size samples. No severe adverse events occurred.

CONCLUSIONS

Psychedelics are promising treatments for anxiety, depression and addiction, their efficacy is quick and sustainable, and they are well tolerated. These effects need to be confirmed in larger studies and compared to standard care.

A longitudinal case series of IM ketamine for patients with severe and enduring eating disorders and comorbid treatment-resistant depression

Severe and enduring eating disorders (EDs) have the highest mortality rate of all psychiatric illnesses (Arch Gen Psychiatry, 2011, 68, 724), especially when comorbid with treatment‐resistant depression (TRD) (Psychiatr Res, 2016, 244, 45). We report on four patients with enduring EDs and TRD treated with repeat ketamine over 12 + months, showing improvement in depression with only modest changes in ED symptoms.

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

OBJECTIVE

Patients with major depressive disorder often have limited response to first-line and second-line medications; hence, novel pharmacological treatments are needed for treatment-resistant depression (TRD). Ketamine, an N-methyl-d-aspartate (NMDA) receptor antagonist, has demonstrated rapid antidepressant effects in patients with TRD. The Canadian Network for Mood and Anxiety Treatments (CANMAT) convened a task force to review the evidence for efficacy and safety of racemic ketamine and to provide recommendations for its use in clinical practice.

METHODS

A systematic review was conducted with computerized search of electronic databases up to January 31, 2020 using combinations of search terms, inspection of bibliographies, and review of other ketamine guidelines and consensus statements. The level of evidence and lines of treatment were assigned according to CANMAT criteria. Recommendations were given in question-answer format.

RESULTS

Intravenous (IV) racemic ketamine given as a single infusion has Level 1 evidence for efficacy in adults with TRD. The evidence for multiple infusions, given as an acute series or as ongoing maintenance treatment, is limited to Level 3. Adverse events associated with ketamine infusions include behavioral (e.g., dissociative symptoms) and physiological (e.g., hypertension) events. There is only Level 3 or 4 evidence for non-IV formulations of racemic ketamine. Consensus recommendations are given for clinical administration of IV ketamine including patient selection, facility and personnel issues, monitoring, and maintaining response.

CONCLUSIONS

Single-dose IV racemic ketamine is a third-line recommendation for adults with TRD. The need for repeated and maintenance ketamine infusions should be carefully assessed on a case-by-case basis with consideration of potential risks and benefits. Because of limited evidence for efficacy and risk for misuse and diversion, the use of oral and other formulations of racemic ketamine should be limited to specialists with ketamine-prescribing expertise and affiliations with tertiary or specialized centers.

Increased use of ketamine for the treatment of depression: Benefits and concerns

Ketamine was initially used as an anesthetic which could induce cognitive impairment and psychomimetic effects. In initial randomized controlled trials (RCTs) that mostly included a small sample size and were investigator-initiated, ketamine reportedly exerted antidepressant effects 1 to 2 h after a single intravenous infusion in patients with major depressive episodes, particularly treatment-resistant depression (TRD). Interest in ketamine was reported in systematic reviews and meta-analyses, however, many were primarily focused on the rapid onset of ketamine effects without equal attention to its safety and tolerability. Furthermore, several meta-analyses were based on many duplicated RCTs. The initial trends emphasized the clinical utility of ketamine as an antidepressant. The development of esketamine nasal spray by a pharmaceutical company led to an RCT with a large sample size and segmented therapeutic strategy, which provided results applicable to patients with TRD in the real-world clinical environment. However, possible effects of ketamine on cognitive function have not yet been investigated in RCTs. In numerous studies, chronic, recreational use of ketamine reportedly substantially impaired cognitive function in most domains. Although results of several human and animal studies indicated the therapeutic use of ketamine for treatment of depression did not induce cognitive impairment, this issue should be further investigated. Based on the current knowledge about ketamine, future antidepressants are expected to be glutamatergic drugs without ketamine-like adverse events (e.g., psychomimetic symptoms and cognitive impairment), but having only ketamine-like therapeutic properties (e.g., rapid antidepressants effects without time lag).

Factors associated with the absence of cocaine craving in treatment-seeking individuals during inpatient cocaine detoxification

BACKGROUND

Anecdotal evidence suggests a substantial proportion of individuals with cocaine use disorder do not report craving during inpatient detoxification.

OBJECTIVE

To examine prevalence and clinical correlates of consistent absence of cocaine craving among inpatients during detoxification. We hypothesized that craving absence would be associated with less severity of cocaine use, depression, and anxiety. Alternative explanations were also explored.

METHODS

Craving absence (i.e., non-cravers) was defined as a daily score of zero across two separate craving visual analogue scales in each of the inpatient days. Participants scoring ≥1 on ≥1 day were considered cravers. Severity of cocaine use disorder as well as in-treatment depression and anxiety were assessed. Alternative contributors included presence of cocaine and other substances in urine at admission, in-treatment prescription of psychotropic medications, treatment motivation, executive function, interoception, and social desirability.

RESULTS

Eighty-seven participants (78.2% males) met criteria as either non-cravers (n = 29; 33.3%) or cravers (n = 58; 66.7%). Mean length of admission in non-cravers and cravers was, respectively, 10.83 and 13.16 days. Binary logistic regression model showed that non-cravers scored significantly lower than cravers on cocaine use during last month before treatment (OR, 95% CI; 0.902, 0.839-0.970), in-treatment depression (OR, 95% CI; 0.794, 0.659-0.956), and in-treatment prescribing of antipsychotics (OR, 95% CI; 0.109, 0.014-0.823). Model prediction accuracy was 88.9%.

CONCLUSIONS

One in three patients undergoing inpatient detoxification experienced absence of craving, linked to less pretreatment cocaine use, better mood, and decreased administration of antipsychotics. Findings may inform pretreatment strategies and improve treatment cost-effectiveness.

Depression, Estrogens, and Neuroinflammation: A Preclinical Review of Ketamine Treatment for Mood Disorders in Women

Ketamine has been shown to acutely and rapidly ameliorate depression symptoms and suicidality. Given that women suffer from major depression at twice the rate of men, it is important to understand how ketamine works in the female brain. This review explores three themes. First, it examines our current understanding of the etiology of depression in women. Second, it examines preclinical research on ketamine's antidepressant effects at a neurobiological level as well as how ovarian hormones present a unique challenge in interpreting these findings. Lastly, the neuroinflammatory hypothesis of depression is highlighted to help better understand how ovarian hormones might interact with ketamine in the female brain.

An Integrative Approach to Ketamine Therapy May Enhance Multiple Dimensions of Efficacy: Improving Therapeutic Outcomes With Treatment Resistant Depression

Research over the last two decades has established ketamine as a safe, effective, fast-acting, and sustained antidepressant that significantly reduces adverse symptoms associated with depression, even in patients who are treatment resistant. Much of this research has evolved within the framework of several independent branches of scientific inquiry: in addition to the study of ketamine is a non-selective NMDAR antagonist with rapid antidepressant effects, it has also been found effective as a psychoplastogen that stimulates synaptogenesis and increases neuroplasticity, as a powerful anti-inflammatory that may improve inflammation-related depressive symptoms, as a substance that induces beneficial high entropy brain states, and as a subjectively impactful psychedelic agent. Each branch of inquiry has generated independent evidence of ketamine's efficacy but has advanced without substantive coordination or communication with other lines of inquiry. Integrative research that considers these branches of research together may lead toward a better understanding of ketamine's effects and improved treatment protocols and clinical outcomes. Such an overview can inform more comprehensive patient care through: (a) informed patient psychoeducation that encompasses all of ketamine's mechanisms of action; (b) calibration of optimal dosage to ensure induction and maintenance of high entropy brain states during each ketamine session utilizing EEG measurement; (c) Improved management of emergence side effects through proper care for set and setting; (d) inclusion of pre-selected appropriate music to enhance the emotional experience; (e) increased monitoring of ketamine effects on cortical activity, inter-hemispheric imbalance, and inflammation-related levels of cytokines to further improvements in ketamine protocols; and (f) appropriate timing of any adjunctive psychotherapy sessions to coincide with peak neurogenesis at 24-48 h post ketamine treatment.

Total Sleep Deprivation Followed by Bright Light Therapy as Rapid Relief for Depression: A Pragmatic Randomized Controlled Trial

Background: Total sleep deprivation (TSD) combined with bright light therapy (BLT) has been suggested as a valuable add-on to standard treatment for rapid relief of depression. However, there is a lack of randomized controlled trials in real-life clinical settings. The aim of this pragmatic randomized clinical trial was to investigate the effectiveness, acceptance, and feasibility of TSD combined with BLT as add-on to standard treatment for depression in a real-life clinical setting. Methods: Thirty-three inpatients were randomly assigned to either: a) an intervention group receiving a single-night TSD followed by 6 days BLT (10.000 lux, 30 min/day) as add-on to standard treatment; or b) a control group receiving a short sleep-hygiene consultation in addition to standard treatment. The follow-up period was 1 week. Results: No statistical differences were found in response rates, reduction of depressive and insomnia symptoms, length of stay, readmission rate, and clinical improvement. Both groups reported positive experiences toward the received treatment with low drop-out rates. Conclusions: One-night TSD followed by BLT was not effective as a rapid relief for depression at 1-week follow-up; however, the treatment was feasible and well-tolerated.

Involvement of NMDA receptors containing the GluN2C subunit in the psychotomimetic and antidepressant-like effects of ketamine

Acute ketamine administration evokes rapid and sustained antidepressant effects in treatment-resistant patients. However, ketamine also produces transient perceptual disturbances similarly to those evoked by other non-competitive NMDA-R antagonists like phencyclidine (PCP). Although the brain networks involved in both ketamine actions are not fully understood, PCP and ketamine activate thalamo-cortical networks after NMDA-R blockade in GABAergic neurons of the reticular thalamic nucleus (RtN). Given the involvement of thalamo-cortical networks in processing sensory information, these networks may underlie psychotomimetic action. Since the GluN2C subunit is densely expressed in the thalamus, including the RtN, we examined the dependence of psychotomimetic and antidepressant-like actions of ketamine on the presence of GluN2C subunits, using wild-type and GluN2C knockout (GluN2CKO) mice. Likewise, since few studies have investigated ketamine's effects in females, we used mice of both sexes. GluN2C deletion dramatically reduced stereotyped (circling) behavior induced by ketamine in male and female mice, while the antidepressant-like effect was fully preserved in both genotypes and sexes. Despite ketamine appeared to induce similar effects in both sexes, some neurobiological differences were observed between male and female mice regarding c-fos expression in thalamic nuclei and cerebellum, and glutamate surge in prefrontal cortex. In conclusion, the GluN2C subunit may discriminate between antidepressant-like and psychotomimetic actions of ketamine. Further, the abundant presence of GluN2C subunits in the cerebellum and the improved motor coordination of GluN2CKO mice after ketamine treatment suggest the involvement of cerebellar NMDA-Rs in some behavioral actions of ketamine.

The next psychoactive drugs: From imipramine to ketamine

Since the 1950s, the therapeutic arsenal against depression has grown considerably. From the discovery of mono-amine oxidase inhibitors (MAOIs) to the antidepressant effect of ketamine, several pharmacological breakthroughs made the history of psychiatry. These discoveries oriented the research about the pathophysiology of depression, which is one of the most disabling diseases worldwide affecting 10 to 20% of general population. In this article, we offer a short historical review of the various therapeutic options developed over the past century and the consequences of these innovations. We then review the discovery of the antidepressant effects of ketamine (and its S-enantiomer, esketamine), the lastest development in depression treatment. Ketamine's effects are spectacular both in terms of their very short onset time, and because they are observed even in treatment-resistant depression. Just as MAOIs and tricyclic antidepressants allowed the "monoaminergic hypothesis of depression" to emerge, unravelling the mechanisms of ketamine's antidepressant effects should highlight the role of glutamatergic system and neuro-inflammation in the neurobiology of depression. Ketamine might also help to refine our understanding of the cognitive pathophysiology of depression and to deeply transform the clinical representations of depressive disorder.

The probability of response after each subcutaneous injection of esketamine in treatment-resistant depression

INTRODUCTION

The administration of multiple esketamine doses has shown efficacy for unipolar and bipolar treatment-resistant depression (TRD). Nevertheless, the probability of responding or not after each dose in the real-world remains unknown. This study aimed to estimate it throughout four doses of esketamine, administrated via subcutaneous (SC).

MATERIAL AND METHODS

We conducted a retrospective analysis of a case series of 70 patients with TRD who received treatment from the esketamine assistance program at Federal University of Sao Paulo, between April 2017 and December 2018. The SC injections were administrated weekly at a dose of 0.5-1.0mg/kg, in conjunction with patients' psychotropic drugs. Response was defined as a decrease of at least 50% in the Montgomery-Åsberg Depression Rating Scale between baseline and 24h after dose. We used hidden Markov modeling in order to estimate de probability of response after each esketamine injection.

RESULTS

The probability of a patient that was a "non-responder" to become a "responder" following a SC injection of esketamine was 17.30% and the probability that this patient remains a "non-responder" was 82.70%. The probability of a patient that was a "responder" to remain as a "responder" was 95%.

CONCLUSIONS

Patients with TRD who had not responded after the first dose of esketamine, still had a chance of responding after the subsequent dose administrated via SC.

Efficacy of psychedelic treatments on depressive symptoms: A meta-analysis

BACKGROUND

Psychedelic drugs have shown an efficacy in some psychiatric disorders and have an original mechanism of action with a 5-HT_2A agonism.

AIM

The aim of this meta-analysis was to assess by a quantitative analysis the putative efficacy of psychedelic drugs on depressive symptoms and to investigate the kinetic of this efficacy.

METHODS

We searched the MEDLINE and PsycINFO databases through April 2019, without limits on year of publication. Means and standard deviations were extracted to calculate standardized mean differences (SMD). Scores of depressive symptoms were compared with baseline scores at days 7, 14, and 21; weeks 4-5 and 6-8; and months 3 and 6.

RESULTS

Eight studies were included in this meta-analysis. A significant decrease of depressive symptoms was found from day 1 (n = 5 studies; SMD = ‒1.4, 95% confidence interval (CI): ‒2.33 to ‒0.48, p = 0.003) to 6 months (n = 4 studies; SMD = ‒1.07, 95% CI: ‒1.44 to ‒0.7, p < 0.001) after psychedelic sessions. No serious adverse effect was reported in all included studies. A transient increase of the heart rate, blood systolic, and diastolic pressure were found after psychedelics compared with placebo.

CONCLUSION

This meta-analysis shows that psychedelic treatments were safe and could contribute to a rapid improvement of depressive symptoms.

[The next psychoactive drugs: From imipramine to ketamine]

Depuis les années 1950, l’arsenal thérapeutique permettant de lutter contre la dépression s’est considérablement enrichi. De la découverte des inhibiteurs de la monoamine oxydase (IMAO) à celle de la kétamine, ces percées pharmacologiques ont marqué l’histoire de la psychiatrie et guidé la recherche sur la physiopathologie de la dépression, cette pathologie dévastatrice affectant entre 10 et 20 % de la population mondiale. Nous proposons dans cet article une courte revue historique des différentes options thérapeutiques développées au cours du siècle passé et des conséquences qu’ont eu ces innovations. Nous réalisons ensuite un état des lieux de la plus récente de ces découvertes, celle des effets antidépresseurs de la kétamine (et de son énantiomère S, l’eskétamine), spectaculaires de par leur délai d’apparition et leur efficacité même dans les formes les plus résistantes de dépression. De même que la découverte des IMAO et des tricycliques a permis de concevoir une théorie monoaminergique de la dépression, l’étude des mécanismes d’actions de la kétamine pourrait permettre de comprendre le rôle de la transmission glutamatergique ou de la neuro-inflammation dans la neurobiologie de cette pathologie, d’affiner nos connaissances sur sa physiopathologie cognitive ou encore de transformer en profondeur les représentations des cliniciens sur cette maladie.

Intravenous Ketamine Administered as Patient Controlled Analgesia and Continuous Infusion for Central Pain Syndrome

Treatment of Central Pain Syndrome (CPS) is known to be extremely challenging. Current therapies are unsatisfactory as patients report only mild to moderate pain relief. We report a case of using ketamine as a patient-controlled analgesia (PCA) for the treatment of CPS. A 58-year-old male with CPS presented with severe generalized body pain refractory to multiple pharmacological interventions. He was started on a basal infusion rate at 0.3 mg/kg/h with a ketamine PCA bolus of 10 mg with a 10-minute lockout period. Over the next 7 days, the basal infusion rate was titrated up to 2.1 mg/kg/h relative to the number of times the patient pressed the PCA. At the end of the trial, the patient reported 0/10 pain with lightheadedness on the first day being the only side effect reported. He was discharged home with his regular pain regimen, with significant decrease in pain over the next few months. Rather than trying to establish a "one size fits all" protocol for ketamine infusions, this case illustrates a shift in pain management focus by allowing patients to self-titrate and demonstrates the potential for using ketamine PCA as a treatment option for CPS.

Pharmacological Treatment of Bipolar Depression: What are the Current and Emerging Options?

Depression accounts for the predominant burden associated with bipolar disorder. The identification and management of bipolar depression are challenging, since bipolar depression differs from unipolar depression, responding poorly to traditional antidepressants, which may also induce a switch to hypomania/mania, mixed states and/or cause rapid cycling. Current treatment options for bipolar depression are limited and guidelines vary greatly in their recommendations, reflecting gaps and inconsistencies in the current evidence base. Moreover, some treatment options, such as quetiapine and olanzapine-fluoxetine, although clearly efficacious, may be associated with adverse cardiometabolic side effects, which can be detrimental to the long-term physical health and well-being of patients, increasing the likelihood of treatment non-adherence and relapse. Evidence for some more recent therapeutic options, including lurasidone and cariprazine, suggests that patients' symptoms can be effectively managed without compromising their physical health. In addition, novel agents targeting alternative neurotransmitter pathways and inflammatory processes (such as ketamine and N-acetyl cysteine) are emerging as promising potential options for the treatment of bipolar depression in the future.