Ketamine Anesthesia Does Not Improve Depression Scores in Electroconvulsive Therapy: A Randomized Clinical Trial

Prognostic Factors and Incidence for Postictal Agitation After Electroconvulsive Therapy: A Systematic Review and Meta-analysis

ABSTRACT

Postictal agitation (PIA) is an adverse effect of electroconvulsive therapy (ECT) and is known to predict other side effects of ECT, but inconsistencies in the literature remain regarding PIA prognostic factors and incidence. Therefore, a systematic review and meta-analysis were conducted (1) to identify prognostic factors for PIA following ECT and (2) to elucidate the diverse incidences of PIA following ECT based on demographic and clinical characteristics. Specifically, electronic databases were searched for retrospective observational studies and randomized controlled trials (RCTs) that objectively reported PIA incidence. Additional inclusion criteria encompassed studies involving patients 18 years or older and allowed for the extraction of PIA prognostic factors. This resulted in the inclusion of 21 articles with 66,047 patients in total. A total of 35 prognostic factors were identified for PIA after ECT, consisting of 8 anesthesia-related, 19 patient-related, and 8 ECT-related prognostic factors. A meta-analysis was conducted for 7 prognostic factors. None of the prognostic factors demonstrated a significant effect on reducing or increasing PIA incidence. Mean PIA was 13.9% (18.0% adjusted) at the patient level and 12.4% (16.5% adjusted) at the session level. Overall risk of bias was generally moderate to low, except in the outcome measurement domain, where 43% of the studies had a high risk of bias. Although none of the prognostic factors in meta-analysis were significant, several other prognostic factors consistently indicated increased or decreased risk, providing direction for future research. A scarcity of (high-quality) data emphasizes the need for additional research on this topic to be conducted.

Towards an expanded neurocognitive account of ketamine's rapid antidepressant effects

Ketamine is an N-methyl-D-aspartate receptor antagonist that has shown effectiveness as a rapidly acting treatment for depression. Although advances have been made in understanding ketamine's antidepressant pharmacological and molecular mechanisms of action, the large-scale neurocognitive mechanisms driving its therapeutic effects are less clearly understood. To help provide such a framework, we provide a synthesis of current evidence linking ketamine treatment to the modulation of brain systems supporting reward processing, interoception, and self-related cognition. We suggest that ketamine's antidepressant effects are, at least in part, driven by dynamic multi-level influences across these key functional domains.

Electroconvulsive therapy combined with esketamine improved depression through PI3K/AKT/GLT-1 pathway

Neuron excitotoxic damage induced by extracellular glutamate accumulation pathologically is one of the main mechanisms of depression. Glutamate transporter-1 (GLT-1) expressed in astrocyte is responsible for glutamate clearance to maintain glutamate balance. Electroconvulsive therapy (ECT) is prevalently recommended for severe depression due to its significant anti-depressant effect. Esketamine could offer advantages of rapid anti-depressant effect and neuron protection. The aim of this study is to investigate the anti-depressant efficacy of esketamine plus ECT, and further to explore the mechanism. Firstly, total 12 patients were randomized into anesthesia with propofol (P) or propofol+esketamine (PK) before ECT. 24-Hamilton Depression Scale (HAMD) was used to evaluate the severity of depression after each ECT. Then, depressive rat model was built using chronic unpredictable mild stress method, and subsequently received infusion of esketamine (5 mg/kg) or saline before ECT treatment (0.5 mA; 100 V) for consecutive 10 days. Tests including sucrose preference test, open field test and forced swimming test were used to evaluate depression-like behaviors. In next experiments, rats were injected with RIL, DHK or LY294002 intracerebroventricularly for continuous 10 days before individual treatment. After the fifth and sixth ECT, PK group displayed lower HAMD score compared to P group. In rat model, we found that esketamine plus ECT could significantly improve depression-like behaviors and decrease glutamate level. Esketamine and ECT could both activate PI3K/Akt/GLT-1 pathway. The GLT-1 agonist RIL made equivalent effect as esketamine plus ECT. Furthermore, after using PI3K/Akt inhibitor LY294002 and GLT-1 inhibitor DHK, esketamine plus ECT could neither improve depression-like symptoms, nor upregulate GLT-1 level. Our present study suggested that esketamine plus ECT could dramatically improve depression symptom. The activation of PI3K/Akt/GLT-1 pathway may be the potential mechanism.

The effect of antidepressant treatment on blood BDNF levels in depressed patients: A review and methodological recommendations for assessment of BDNF in blood

Major depressive disorder (MDD) is a highly prevalent psychiatric disorder and a leading cause of disability worldwide. Brain-derived neurotrophic factor (BDNF), a signaling protein responsible for promoting neuroplasticity, is highly expressed in the central nervous system but can also be found in the blood. Since impaired brain plasticity is considered a cornerstone in the pathophysiology of MDD, measurement of BDNF in blood has been proposed as a potential biomarker in MDD. The aim of our study is to systematically review the literature for the effects of antidepressant treatments on blood BDNF levels in MDD and the suitability of blood BDNF as a biomarker for depression severity and antidepressant response. We searched Pubmed® and Cochrane library up to March 2024 in a systematic manner using Medical Subject Headings (MeSH). The search resulted in a total of 42 papers, of which 30 were included in this systematic review. Generally, we found that patients with untreated MDD have a lower blood BDNF level than healthy controls. Antidepressant treatments increase blood BDNF levels, and more evidently after pharmacological than non-pharmacological treatment. Neither baseline nor change in the blood BDNF level correlates with depression severity or treatment outcome, which undermines its use as a biomarker in MDD. Our review also highlights the importance of considering factors influencing the accuracy and reproducibility of BDNF measurements. We summarize considerations to help obtain more robust blood BDNF values and compile a list of recommendations to help streamline assessment of blood BDNF levels in future studies.

Effects of esketamine on postoperative negative emotions and early cognitive disorders in patients undergoing non-cardiac thoracic surgery: A randomized controlled trial

STUDY OBJECTIVE

To investigate whether a single dosage of esketamine injection in the anesthesia period could improve postoperative negative emotions and early cognitive function in patients undergoing non-cardiac thoracic surgery.

DESIGN

A prospective single center double blinded randomized placebo-controlled trial.

SETTING

Perioperative period; operating room, post anesthesia care unit and hospital ward.

PATIENTS

129 adult patients that underwent elective non-cardiac thoracic surgery under general anesthesia.

INTERVENTIONS

During the operation, pharmacologic prevention of postoperative negative emotion and early cognitive disorder with 0.2 mg/kg (Low esketamine group) and 0.5 mg/kg esketamine (High esketamine group) vs. placebo.

MEASUREMENTS

Emotion and early cognitive performance were assessed on the day before surgery (POD-1), postoperative day 1 (POD1) and day 3 (POD3) using HADS-A, HADS-D, Pain Visual Analogue Scale (VAS), Confusion Assessment Method (CAM), Mini-Mental State Examination (MMSE), and serum biomarkers (S100β, BDNF, IL-6, acetylcholine, and norepinephrine).

MAIN RESULTS

The high esketamine group showed significantly lower HADS-A and HADS-D scores than control group on POD1 and POD3. No significant differences were observed between the low esketamine group and the control group. The esketamine-treated groups showed lower pain VAS scores than the control group at 2 h and on the first day after operation. There were no significant differences among the three groups in CAM and MMSE scores. However, the high esketamine group had lower S100β and IL-6 levels, and higher BDNF levels postoperatively, while serum acetylcholine and norepinephrine were not significantly different.

CONCLUSIONS

A single intraoperative injection of 0.5 mg/kg esketamine can alleviate postoperative anxiety, depression, and pain to some extent. Although cognitive function behavioral evaluation did not show obvious benefits, it can also reduce the production of pro-inflammatory and brain injury-related factors while promoting the generation of brain-derived neurotrophic factor. Registration Trial registry: http://www.chictr.org.cn/; Identifier: ChiCTR2100047067.

Ketamine as an Alternative Anesthetic for Augmenting Seizure Durations During Electroconvulsive Therapy: A Retrospective Observational Study

OBJECTIVE

Electroconvulsive therapy (ECT) is highly effective for severe psychiatric disorders; however, short seizure durations may lead to ineffective therapy. This retrospective study aimed to examine the risks and benefits of switching to ketamine anesthesia to augment seizure durations during an acute course of ECT.

METHODS

We included 33 patients who underwent ketamine anesthesia due to suboptimal seizures during an acute course of ECT. We assessed seizure duration, stimulus dose, hemodynamic variability, and postseizure complications before and after switching to ketamine.

RESULTS

Age was significantly associated with suboptimal seizures during ECT ( P = 0.040). After switching to ketamine, 32 patients (97%) experienced prolonged seizure duration. Ketamine significantly prolonged both electroencephalogram and motor seizure durations with a mean difference of 34.6 seconds (95% confidence interval [CI], 26.4-42.7 seconds; P < 0.001) and 26.6 seconds (95% CI, 19.6-33.6 seconds; P < 0.001), respectively. It also significantly reduced stimulus dose (mean difference, -209.5 mC [95% CI, -244.9 to -174.1 mC]; P < 0.001). In addition, maximum changes in systolic blood pressure and heart rate during ECT sessions significantly increased with ketamine (mean difference, 27.2 mm Hg [95% CI, 12.0-42.4 mm Hg; P = 0.001]; 25.7 beats per minute [95% CI, 14.5-36.8 beats per minute; P < 0.001], respectively). Patients reported more headaches with ketamine ( P = 0.041).

CONCLUSIONS

Our results provide evidence that ketamine as an alternative anesthetic can augment seizure durations in specific patients experiencing suboptimal seizures during an acute course of ECT. However, its use requires greater attention to circulatory management and postseizure complications.

Electroconvulsive Therapy Across Nations: A 2022 Survey of Practice

OBJECTIVES

We aimed to characterize worldwide electroconvulsive therapy (ECT) practice and compare practice across nations and global regions.

METHOD

Our anonymous survey was open on SurveyMonkey.com from January to June 2022. We sent invitations to providers identified using a Medicare provider database, an advanced PubMed search function, and professional group listservs. Participants were instructed to submit one survey per ECT site. Response frequencies were pooled by global region and compared using nonparametric methods.

RESULTS

Responses came from 126 sites, mostly in the United States (59%, n = 74), Europe (18%, n = 23), Canada (10%, n = 12), and South/East Asia (6%, n = 8). With some exceptions, sites were broadly consistent in practice as indicated by: a likely shift internationally from bitemporal to right unilateral electrode placement; predominant use of pulse widths <1 ms; preference for seizure threshold titration over age-based dosing methods; widespread availability of continuation/maintenance ECT (97%); and frequent use of quantitative outcome measures for depressive symptoms (88%) and cognitive adverse effects (80%).

CONCLUSIONS

This is the first, published survey that aimed to characterize worldwide ECT practice. With some exceptions, responses suggest a concordance in practice. However, responses were primarily from the Global North. To obtain a truly worldwide characterization of practice, future surveys should include more responses from the Global South.

Recent Advances in the Treatment of Treatment-Resistant Depression: A Narrative Review of Literature Published from 2018 to 2023

PURPOSE OF REVIEW

We review recent advances in the treatment of treatment-resistant depression (TRD), a disorder with very limited treatment options until recently. We examine advances in psychotherapeutic, psychopharmacologic, and interventional psychiatry approaches to treatment of TRD. We also highlight various definitions of TRD in recent scientific literature.

RECENT FINDINGS

Recent evidence suggests some forms of psychotherapy can be effective as adjunctive treatments for TRD, but not as monotherapies alone. Little recent evidence supports the use of adjunctive non-antidepressant pharmacotherapies such as buprenorphine and antipsychotics for the treatment of TRD; side effects and increased medication discontinuation rates may outweigh the benefits of these adjunctive pharmacotherapies. Finally, a wealth of recent evidence supports the use of interventional approaches such as electroconvulsive therapy, ketamine/esketamine, and transcranial magnetic stimulation for TRD. Recent advances in our understanding of how to treat TRD have largely expanded our knowledge of best practices in, and efficacy of, interventional psychiatric approaches. Recent research has used a variety of TRD definitions for study inclusion criteria; research on TRD should adhere to inclusion criteria based on internationally defined guidelines for more meaningfully generalizable results.

Efficacy and safety of ketamine-assisted electroconvulsive therapy in major depressive episode: a systematic review and network meta-analysis

OBJECTIVE

To meta-analyze clinical efficacy and safety of ketamine compared with other anesthetic agents in the course of electroconvulsive therapy (ECT) in major depressive episode (MDE).

METHODS

PubMed/MEDLINE, Cochrane Library, Embase, GoogleScholar, and US and European trial registries were searched from inception through May 23, 2023, with no language limits. We included RCTs with (1) a diagnosis of MDE; (2) ECT intervention with ketamine and/or other anesthetic agents; and (3) measures included: depressive symptoms, cognitive performance, remission or response rates, and serious adverse events. Network meta-analysis (NMA) was performed to compare ketamine and 7 other anesthetic agents. Hedges' g standardized mean differences (SMDs) were used for continuous measures, and relative risks (RRs) were used for other binary outcomes using random-effects models.

RESULTS

Twenty-two studies were included in the systematic review. A total of 2322 patients from 17 RCTs were included in the NMA. The overall pooled SMD of ketamine, as compared with propofol as a reference group, was -2.21 (95% confidence interval [CI], -3.79 to -0.64) in depressive symptoms, indicating that ketamine had better antidepressant efficacy than propofol. In a sensitivity analysis, however, ketamine-treated patients had a worse outcome in cognitive performance than propofol-treated patients (SMD, -0.18; 95% CI, -0.28 to -0.09). No other statistically significant differences were found.

CONCLUSIONS

Ketamine-assisted ECT is tolerable and may be efficacious in improving depressive symptoms, but a relative adverse impact on cognition may be an important clinical consideration. Anesthetic agents should be considered based on patient profiles and/or preferences to improve effectiveness and safety of ECT use.

Comparative efficacy and tolerability of different anesthetics in electroconvulsive therapy for major depressive disorder: A systematic review and network meta-analysis

Electroconvulsive therapy (ECT) is one of the most effective treatments for major depressive disorder. Modern ECT is conducted with anesthesia, however, the optimal anesthetic agent for ECT is yet to be understood. This study is aimed to compare the effects of different anesthetic agents on antidepressant efficacy and tolerability in depressed individuals undergoing ECT. We searched MEDLINE, EMBASE, the CENTRAL and PsycINFO for randomized controlled trials from database inception until Nov 13, 2022 (PROSPERO: CRD42022375407). Global and local inconsistencies, heterogeneity and publication bias were assessed. Rankings were calculated with the surface under the cumulative ranking curve. A total of 33 studies involving 1898 patients were enrolled. Remission rates were higher for ketamine anesthesia as compared to adjunctive ketamine and propofol. In terms of ranking, ketamine was found to be first in terms of response/remission rates and depressive scores after the 1st, 3rd and 6th ECT and at the end of ECT session, while a higher incidence of adverse events was also observed. No significant advantage of any anesthetic was revealed for the cognitive function after ECT. In summary, based on current evidence, no specific anesthetic is recommended for ECT anesthesia. However, despite more side effects, ketamine monoanesthesia seems to reveal a potential benefit in improving antidepressant efficacy of ECT, and further studies are needed to investigate the relationship between anesthetic agents and the therapeutic effect of ECT.

Rapid-acting antidepressant drugs modulate affective bias in rats

How rapid-acting antidepressants (RAADs), such as ketamine, induce immediate and sustained improvements in mood in patients with major depressive disorder (MDD) is poorly understood. A core feature of MDD is the prevalence of cognitive processing biases associated with negative affective states, and the alleviation of negative affective biases may be an index of response to drug treatment. Here, we used an affective bias behavioral test in rats, based on an associative learning task, to investigate the effects of RAADs. To generate an affective bias, animals learned to associate two different digging substrates with a food reward in the presence or absence of an affective state manipulation. A choice between the two reward-associated digging substrates was used to quantify the affective bias generated. Acute treatment with the RAADs ketamine, scopolamine, or psilocybin selectively attenuated a negative affective bias in the affective bias test. Low, but not high, doses of ketamine and psilocybin reversed the valence of the negative affective bias 24 hours after RAAD treatment. Only treatment with psilocybin, but not ketamine or scopolamine, led to a positive affective bias that was dependent on new learning and memory formation. The relearning effects of ketamine were dependent on protein synthesis localized to the rat medial prefrontal cortex and could be modulated by cue reactivation, consistent with experience-dependent neural plasticity. These findings suggest a neuropsychological mechanism that may explain both the acute and sustained effects of RAADs, potentially linking their effects on neural plasticity with affective bias modulation in a rodent model.

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.

Subanesthetic Dose of Ketamine Administered Before Each Electroconvulsive Therapy Session Improves Antidepressant and Sleep Quality Outcomes: A Randomized, Controlled Trial

OBJECTIVES

The main purpose of this trial is to explore the effects of subanesthetic dose of ketamine on sleep quality and symptoms in patients with major depressive disorder undergoing bitemporal electroconvulsive therapy (ECT).

METHODS

Seventy-one patients with major depressive disorder and sleep disturbance were randomly divided into 2 groups, namely, the ECT without ketamine group (group ES), receiving routine ECT and saline (3 mL) at each ECT session, and the ECT-assisted ketamine group (group KS), which received ECT and ketamine (3 mL) at each ECT session. The 24 Hamilton Depression Rating Scale was used to assess depressive symptoms and the Chinese Pittsburgh Sleep Quality Index was used to evaluate sleep quality.

RESULTS

The patients in group KS required shorter ECT treatment sessions. Patients in group ES had lower sleep efficiency, longer sleep latency, and required more sleep medication than patients in group KS at the end of the ECT course.

CONCLUSIONS

Subanesthetic dose of ketamine improved sleep quality and enhanced ECT therapeutic effects in patients with sleep disturbance.

Plasma Brain-Derived Neurotrophic Factor Levels in First-Episode and Recurrent Major Depression and before and after Bright Light Therapy in Treatment-Resistant Depression

Brain-derived neurotrophic factor (BDNF) is implicated in the etiology and treatment response in major depressive disorder (MDD). However, peripheral BDNF concentrations have not been compared across different MDD stages. Bright light therapy (BLT) offers some potential in treatment-resistant depression (TRD), but its effects on BDNF levels are unknown. This study included a cross-sectional analysis of plasma BDNF concentration in females with TRD, unmedicated MDD patients, and healthy controls (HC), and measurements of longitudinal BLT effects on plasma BDNF levels in TRD patients. The present study included 55 drug-naïve, first-episode patients, 25 drug-free recurrent-episode MDD patients, 71 HC participants, and 54 TRD patients. Patients were rated by Hamilton Depression Rating Scale (HAMD)-17 and the Montgomery-Åsberg Depression Rating Scale (MADRS). Patients with TRD received BLT during 4 weeks. The total HAMD-17 and MADRS scores decreased following BLT. All patient groups had lower plasma BDNF than HC, but BDNF levels did not differ between first- and recurrent-episode BDNF patients and TRD patients before or after BLT. However, responders and remitters to BLT had higher post-treatment plasma BDNF concentrations than patients who did not achieve response or remission. The changes in plasma BDNF levels may be candidates for biomarkers of treatment response to BLT in TRD patients.

Efficacy and Safety of Ketamine-assisted Electroconvulsive Therapy in Major Depressive Episode: A Systematic Review and Network Meta-Analysis

Objective

To meta-analyze clinical efficacy and safety of ketamine compared with other anesthetic agents in the course of electroconvulsive therapy (ECT) in major depressive episode (MDE).

Methods

PubMed/MEDLINE, Cochrane Library, Embase, GoogleScholar, and US and European trial registries were searched from inception through May 23, 2023, with no language limits. We included RCTs with (1) a diagnosis of MDE; (2) ECT intervention with ketamine and/or other anesthetic agents; and (3) measures included: depressive symptoms, cognitive performance, remission or response rates, and serious adverse events. Network meta-analysis (NMA) was performed to compare ketamine and 7 other anesthetic agents. Hedges' g standardized mean differences (SMDs) were used for continuous measures, and relative risks (RRs) were used for other binary outcomes using random-effects models.

Results

Twenty-two studies were included in the systematic review. A total of 2,322 patients from 17 RCTs were included in the NMA. The overall pooled SMD of ketamine, as compared with a propofol reference group, was -2.21 (95% confidence interval [CI], -3.79 to -0.64) in depressive symptoms, indicating that ketamine had better antidepressant efficacy than propofol. In a sensitivity analysis, however, ketamine-treated patients had a worse outcome in cognitive performance than propofol-treated patients (SMD, -0.18; 95% CI, -0.28 to -0.09). No other statistically significant differences were found.

Conclusions

Ketamine-assisted ECT is tolerable and may be efficacious in improving depressive symptoms, but a relative adverse impact on cognition may be an important clinical consideration. Anesthetic agents should be considered based on patient profiles and/or preferences to improve effectiveness and safety of ECT use.

Ketamine Augmentation of Electroconvulsive Therapy: A Scoping Review of Dose-Dependent Effects in Major Depressive Disorder

Intravenous ketamine infusions in subanesthetic doses have been shown to rapidly alleviate depressive symptoms. However, the efficacy of ketamine as an anesthetic during electroconvulsive therapy (ECT) for major depression has not yet been answered by a large randomized control trial (RCT). This scoping review aims to examine the available literature to determine whether the dose of ketamine used during ECT influences the response to treatment. A literature search was conducted on PubMed to identify all published RCTs within the last 10 years which compared ketamine anesthesia during ECT for major depression with another anesthetic. Studies using low (<0.8 mg/kg) versus high (≥0.8 mg/kg) doses of ketamine during ECT were evaluated for the differences in outcomes using depression rating scales. Studies that examined ketamine as a standalone treatment for depression or focused primarily on the anesthetic benefits of ketamine were excluded from our review. Fifteen studies were utilized for this literature review. Overall, the studies showed inconsistent results in terms of the speed and magnitude of response to ketamine-assisted ECT in patients with major depression. Limitations of the available literature are discussed, including the lack of head-to-head comparisons, differences in methodology, inclusion/exclusion criteria, and primary and secondary endpoints.

Effects of Anesthesia Changes During Maintenance ECT: A Longitudinal Comparison of Seizure Quality Under Anesthesia Using Propofol/Esketamine Versus Methohexital

INTRODUCTION

The effectiveness of ECT relies on the induction of a generalized cerebral seizure. Among others, seizure quality (SQ) is potentially influenced by the anesthetic drug used. Commonly used anesthetics comprise barbiturates, etomidate, propofol, and esketamine, with different characteristics and impacts on seizure parameters. So far, no studies have compared the influence of methohexital vs. a combination of propofol/esketamine on established SQ parameters.

METHODS

This retrospective longitudinal study compared eight established SQ parameters (PSI, ASEI, MSC, midictal amplitude, motor and electroencephalography (EEG) seizure duration, concordance, PHR) before and after the change from propofol/esketamine to methohexital in 34 patients under maintenance ECT. Each patient contributed four measurements, two before and two after the anesthesia change. Anesthesia dose, stimulus dose, electrode placement, and concomitant medication remained unchanged throughout the analyzed treatments.

RESULTS

Under methohexital (M=88.97 mg), ASEI (p=0.039 to 0.013) and midictal amplitude (p=0.022 to<0.001) were significantly lower, whereas seizure duration (motor and EEG) was significantly longer when compared to propofol/esketamine (M=64.26 mg/51.18 mg; p=0.012 to<0.001). PSI, MSC, seizure concordance, and PHR were not affected by the anesthetic used.

DISCUSSION

Although to what extent these parameters correlate with the therapeutic effectiveness remains ambiguous, a decision for or against a particular anesthetic could be considered if a specific SQ parameter needs optimization. However, no general superiority for one specific substance or combination was found in this study. In the next step, anesthetic effects on treatment response and tolerability should be focused on.

BDNF blood levels after electroconvulsive therapy in patients with mood disorders: An updated systematic review and meta-analysis

OBJECTIVES

Studies have suggested Brain-Derived Neurotrophic Factors (BDNF) increase after electroconvulsive therapy (ECT) although they were methodologically limited and enrolled small sample sizes. We aimed at updating a systematic review and meta-analysis to explore BDNF changes after ECT for the treatment of depression.

METHODS

PubMed, PsycInfo, Embase and Global health were searched (March, 2021). Clinical trials that measured BDNF in the blood before and after ECT in adults (≥ 18 years old) with depression (major depressive disorder or bipolar disorder) were eligible. Data were pooled through random-effects meta-analyses.

RESULTS

Twenty-eight studies involving 778 participants were included. Meta-analysis showed a significant increase in BDNF levels after ECT (Hedges' g = 0.28; 95% CI: 0.10, 0.46) while there was evidence of significant heterogeneity (I² = 67.64%) but not publication bias/small-study effect. Subgroup analyses and meta-regressions were underpowered to detect significant differences. Meta-analysis of depression severity scores demonstrated a considerable larger treatment effect in reducing depressive symptoms after ECT (Hedge's g = -3.72 95% CI: -4.23, -3.21).

CONCLUSION

This updated review showed that BDNF blood levels increased after ECT treatment. However, there was still evidence of substantial heterogeneity and there were limited sample sizes to investigate factors driving the variability of effects across studies. Importantly, the increase in BDNF levels was substantially smaller than the observed in depressive symptomatology, which could be indicative that the former was independent than the latter. Additional studies with larger sample sizes are currently required.

A Chinese Classical Prescription Chaihu Shugan Powder in Treatment of Post-Stroke Depression: An Overview

Post-stroke depression (PSD) is the most common mental health problem after a stroke with an incidence of up to 33%. PSD has a negative impact on the rehabilitation and recovery of motor and cognitive dysfunction after a stroke and significantly increases the chance of the recurrence of neurovascular events. At present, medication is the preferred method of coping with PSD. Modern medicine is still unclear regarding the pathogenesis of PSD, with clinical drug treatment mostly using antidepressants, such as selective serotonin reuptake inhibitor (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). However, a high proportion of patients fail to show an adequate antidepressant response and have adverse reactions after taking antidepressants. In recent years, as the advantages of traditional Chinese medicine (TCM) in clinical treatment continue to emerge, Chinese herbal and TCM formulae have begun to enter the awareness of Chinese scholars and even scholars around the world. As a classic formula with a history of more than 400 years, Chaihu Shugan powder (CHSG) has great advantages in the clinical treatment of PSD. Based on existing clinical and experimental studies, this article comprehensively analyzes clinical cases, mechanisms of action, and drug and chemical effects of CHSG in the treatment of PSD in order to provide more clinical experience and experimental theoretical support for CHSG in the treatment of PSD.

Brain-Derived Neurotrophic Factor (BDNF) as a biomarker of treatment response in patients with Treatment Resistant Depression (TRD): A systematic review & meta-analysis

Multiple lines of evidence have implicated brain-derived neurotrophic factor (BDNF) in treatment-resistant depression (TRD). The aim of this synthesis was to determine the impact of TRD treatments on peripheral BDNF levels, and ascertain whether these changes are associated with antidepressant effects. Thirty-six articles involving 1198 patients with TRD were included herein. Electroconvulsive therapy (ECT), ketamine, and repetitive transcranial magnetic stimulation (rTMS) were the most common TRD treatments investigated. Serum BDNF levels significantly increased in six, two, four and one studies following ECT, ketamine, rTMS and atypical antipsychotics, respectively. The estimated mean baseline serum BDNF concentration in TRD patients ± 95% CI was 15.5 ± 4.34 ng/mL. Peripheral BDNF levels significantly increased overall (Hedges' g ± 95% CI = 0.336 ± 0.302; p < 0.05), but no association with depressive symptoms was found (p ≥ 0.05). These results demonstrate that peripheral measurements of total BDNF (i.e., mature and percursor forms of BDNF) are inadequate predictors of treatment response in TRD patients, and other considerations suggest that this would still apply to separable measurements of mature BDNF and its precursor.

The Therapeutic Effects of Ketamine in Mental Health Disorders: A Narrative Review

Ketamine, a non-competitive N-methyl-d-aspartate receptor antagonist, is commonly used as an anesthetic and analgesic but has recently shown promising research in treating certain psychiatric conditions such as depression, post-traumatic stress disorder (PTSD), suicidal ideation, and substance use disorder. Due to its euphoric, dissociative, and hallucinogenic properties, ketamine has been abused as a recreational drug, which has led to rigid regulation of medication. The COVID-19 pandemic has been an unprecedented challenge for the American population which was reflected in increased reports of problems regarding their mental health. Mood disorders have dramatically increased in the past two years. Approximately one in ten people stated that they had started or increased substance use because of the COVID-19 pandemic. Furthermore, rates of suicidal ideation have significantly increased when compared to pre-pandemic levels, with more than twice the number of adults surveyed in 2018 indicating suicidal thoughts “within the last 30 days” at the time they were surveyed. Moreover, many responders indicated they had symptoms of PTSD. The PubMed database was searched using the keyword “ketamine,” in conjunction with “depression,” “suicidal ideation,” “substance use disorder,” and “post-traumatic stress disorder.” The inclusion criteria encompassed articles from 2017 to 2022 published in the English language that addressed the relationship between ketamine and mental health disorders. With this sharp increase in the prevalence of psychiatric disorders and an increased public interest in mental health combined with the promise of the therapeutic value of ketamine for certain mental health conditions, including suicidal ideation, this narrative review sought to identify recently published studies that describe the therapeutic uses of ketamine for mental health. Results of this review indicate that ketamine’s therapeutic effects offer a potential alternative treatment for depression, suicidal ideation, substance use disorders, and PTSD.

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.

Ketamine in depression and electroconvulsive therapy

PURPOSE OF REVIEW

The antidepressant effect of subanesthetic doses of ketamine was recognized 20 years ago. This review briefly summarizes the current understanding of the antidepressant mechanisms and the available clinical research on the use of racemic ketamine and enantiomer esketamine for depression.

RECENT FINDINGS

The antidepressant effect of subanesthetic doses of ketamine is currently considered to be predominantly mediated by improved neuroplasticity in cortico-limbic areas in the brain. Single dose of 0.5 mg/kg of ketamine infused intravenously over 40 min, or single intranasal dose of esketamine cause rapid antidepressant and antisuicidal effects within hours of administration, and the antidepressant effect may last up to a week. Repeated administration of nasal spray esketamine is considered to prevent relapse of depression. Longitudinal studies are currently insufficient. When used in various doses for anesthetic induction for electroconvulsive therapy, ketamine improves seizure quality and may possibly diminish posttherapy cognitive impairment.

SUMMARY

A rapid onset antidepressive effect of ketamine and esketamine has been proven conclusively. The results of extensive basic science research of the mechanism of action of low-dose ketamine doses has led to an alternative hypothesis of the pathophysiology of depression and the development of a novel neurotrophic concept of depression. Further longitudinal studies are warranted to determine the safety and efficacy of repeated administration of ketamine and its analogs to prevent relapse and recurrence of depression.

Ketamine and other glutamate receptor modulators for depression in adults with unipolar major depressive disorder

BACKGROUND

Many studies have recently been conducted to assess the antidepressant efficacy of glutamate modification in mood disorders. This is an update of a review first published in 2015 focusing on the use of glutamate receptor modulators in unipolar depression.

OBJECTIVES

To assess the effects - and review the acceptability and tolerability - of ketamine and other glutamate receptor modulators in alleviating the acute symptoms of depression in people with unipolar major depressive disorder.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE, Embase and PsycINFO all years to July 2020.  We did not apply any restrictions to date, language or publication status.

SELECTION CRITERIA

Double- or single-blinded randomised controlled trials (RCTs) comparing ketamine, memantine, esketamine or other glutamate receptor modulators with placebo (pill or saline infusion), other active psychotropic drugs, or electroconvulsive therapy (ECT) in adults with unipolar major depression.

DATA COLLECTION AND ANALYSIS

Three review authors independently identified studies, assessed trial quality and extracted data. The primary outcomes were response rate (50% reduction on a standardised rating scale) and adverse events. We decided a priori to measure the efficacy outcomes at different time points and run sensitivity/subgroup analyses. Risk of bias was assessed using the Cochrane tool, and certainty of the evidence was assessed using GRADE.

MAIN RESULTS

Thirty-one new studies were identified for inclusion in this updated review. Overall, we included 64 studies (5299 participants) on ketamine (31 trials), esketamine (9), memantine (5), lanicemine (4), D-cycloserine (2), Org26576 (2), riluzole (2), atomoxetine (1), basimglurant (1), citicoline (1), CP-101,606 (1), decoglurant (1), MK-0657 (1), N-acetylcysteine (1), rapastinel (1), and sarcosine (1). Forty-eight studies were placebo-controlled, and 48 were two-arm studies. The majority of trials defined an inclusion criterion for the severity of depressive symptoms at baseline: 29 at least moderate depression; 17 severe depression; and five mild-to-moderate depression. Nineteen studies recruited only patients with treatment-resistant depression, defined as inadequate response to at least two antidepressants. The majority of studies investigating ketamine administered as a single dose, whilst all of the included esketamine studies used a multiple dose regimen (most frequently twice a week for four weeks). Most studies looking at ketamine used intravenous administration, whilst the majority of esketamine trials used intranasal routes. The evidence suggests that ketamine may result in an increase in response and remission compared with placebo at 24 hours odds ratio (OR) 3.94, 95% confidence interval (CI) 1.54 to 10.10; n = 185, studies = 7, very low-certainty evidence). Ketamine may reduce depression rating scale scores over placebo at 24 hours, but the evidence is very uncertain (standardised mean difference (SMD) -0.87, 95% CI -1.26 to -0.48; n = 231, studies = 8, very low-certainty evidence). There was no difference in the number of participants assigned to ketamine or placebo who dropped out for any reason (OR 1.25, 95% CI 0.19 to 8.28; n = 201, studies = 6, very low-certainty evidence). When compared with midazolam, the evidence showed that ketamine increases remission rates at 24 hours (OR 2.21, 95% CI 0.67 to 7.32; n = 122,studies = 2, low-certainty evidence). The evidence is very uncertain about the response efficacy of ketamine at 24 hours in comparison with midazolam, and its ability to reduce depression rating scale scores at the same time point (OR 2.48, 95% CI 1.00 to 6.18; n = 296, studies = 4,very low-certainty evidence). There was no difference in the number of participants who dropped out of studies for any reason between ketamine and placebo (OR 0.33, 95% CI 0.05 to 2.09; n = 72, studies = 1, low-certainty evidence). Esketamine treatment likely results in a large increase in participants achieving remission at 24 hours compared with placebo (OR 2.74, 95% CI 1.71 to 4.40; n = 894, studies = 5, moderate-certainty evidence). Esketamine probably results in decreases in depression rating scale scores at 24 hours compared with placebo (SMD -0.31, 95% CI -0.45 to -0.17; n = 824, studies = 4, moderate-certainty evidence). Our findings show that esketamine increased response rates, although this evidence is uncertain (OR 2.11, 95% CI 1.20 to 3.68; n = 1071, studies = 5, low-certainty evidence). There was no evidence that participants assigned to esketamine treatment dropped out of trials more frequently than those assigned to placebo for any reason (OR 1.58, 95% CI 0.92 to 2.73; n = 773, studies = 4,moderate-certainty evidence). We found very little evidence for the remaining glutamate receptor modulators. We rated the risk of bias as low or unclear for most domains, though lack of detail regarding masking of treatment in the studies reduced our certainty in the effect for all outcomes.

AUTHORS' CONCLUSIONS

Our findings show that ketamine and esketamine may be more efficacious than placebo at 24 hours. How these findings translate into clinical practice, however, is not entirely clear. The evidence for use of the remaining glutamate receptor modulators is limited as very few trials were included in the meta-analyses for each comparison and the majority of comparisons included only one study. Long term non-inferiority RCTs comparing repeated ketamine and esketamine, and rigorous real-world monitoring are needed to establish comprehensive data on safety and efficacy.

Low-dose ketamine does not improve the speed of recovery from depression in electroconvulsive therapy: a randomized controlled trial

OBJECTIVE

Electroconvulsive therapy (ECT) is a well-established therapeutic intervention for major depressive disorder. Recent literature has shown that the anesthetic agent ketamine has some antidepressant properties at low doses and may be an alternative therapy for treatment-resistant major depressive disorder. We hypothesized that the use of low-dose ketamine as an anesthetic adjunct in ECT would more rapidly improve depression while maintaining hemodynamic stability than ECT with propofol alone.

METHODS

Institutional ethics approval was obtained, and the use of ketamine in this study was approved by Health Canada. This is a randomized, double-blinded, placebo-controlled trial that involved ketamine administration at 0.5 mg/kg IV in addition to propofol anesthesia for ECT. The primary outcome was the number of ECT treatments required to achieve a 50% reduction in the Montgomery-Asberg Depression Rating Scale (MADRS). Secondary outcomes included the number of ECT treatments required to achieve a 25% reduction in MADRS score, as well as any differences in the Clinical Global Impression Scale for Severity, hemodynamic variables, and seizure duration. Adverse events were recorded for safety assessment.

RESULTS

A total of 45 patients completed the study. No difference was found between groups with respect to the primary or secondary outcomes. The ketamine group showed a trend towards a decreased dose of propofol required to achieve adequate anesthesia. No adverse events were reported.

CONCLUSION

Low-dose ketamine does not improve psychiatric outcomes in the setting of propofol-based anesthesia for ECT. Specifically, ketamine did not reduce the number of ECT sessions necessary to achieve a 50 or 25% reduction in MADRS scores. Reassuringly, the fact that no differences in hemodynamic variables or unexpected adverse events occurred suggests that low-dose ketamine may be safely used in this setting should clinical indications warrant its use.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT02579642.

Serum BDNF levels and the antidepressant effects of electroconvulsive therapy with ketamine anaesthesia: a preliminary study

Objective

To firstly examine the relationship between serum brain-derived neurotrophic factor (BDNF) levels and antidepressant response to ketamine as an anaesthesia in electroconvulsive therapy (ECT) in Chinese patients with treatment-refractory depression (TRD).

Methods

Thirty patients with TRD were enrolled and underwent eight ECT sessions with ketamine anaesthesia (0.8 mg/kg) alone. Depression severity, response and remission were evaluated using the 17-item Hamilton Depression Rating Scale (HAMD-17). Enzyme-linked immunosorbent assay (ELISA) was applied to examine serum BDNF levels in patients with TRD at baseline and after the second, fourth and eighth ECT sessions. Baseline serum samples were also collected for 30 healthy controls.

Results

No significant differences were observed in serum BDNF levels between patients with TRD and healthy controls at baseline (p > 0.05). The remission rate was 76.7% (23/30) after the last ECT treatment, although all patients with TRD obtained antidepressant response criteria. Serum BDNF levels were not altered compared to baseline, even between remitters and nonremitters (all p > 0.05), despite the significant reduction in HAMD-17 and Brief Psychiatric Rating Scale (BPRS) scores after ECT with ketamine anaesthesia (all p < 0.05). The antidepressant effects of ECT with ketamine anaesthesia were not correlated with changes in serum BDNF levels (all p > 0.05).

Conclusion

This preliminary study indicated that serum BDNF levels do not appear to be a reliable biomarker to determine the antidepressant effects of ketamine as an anaesthesia in ECT for patients with TRD. Further studies with larger sample sizes are warranted to confirm these findings.

Ketamine treatment protects against oxidative damage and the immunological response induced by electroconvulsive therapy

BACKGROUND

Electroconvulsive therapy (ECT) is often recommended for major depressive disorder (MDD) for those who do not respond to the first and second antidepressant trials. A combination of two therapies could improve antidepressant efficacy. Thus, this study aimed to investigate the synergistic effects of ECT combined to antidepressants with a different mechanism of action.

METHODS

Rats were treated once a day, for five days with ketamine (5 mg/kg), fluoxetine (1 mg/kg), and bupropion (4 mg/kg) alone or in combination with ECT (1 mA; 100 V). After, oxidative damage and antioxidant capacity were assessed in the prefrontal cortex (PFC) and hippocampus, and pro-inflammatory cytokines levels were evaluated in the serum.

RESULTS

ECT alone increased lipid peroxidation in the PFC and hippocampus. In the PFC of rats treated with ECT in combination with fluoxetine and bupropion, and in the hippocampus of rats treated with ECT combined with ketamine and bupropion there was a reduction in the lipid peroxidation. The nitrite/nitrate was increased by ECT alone but reverted by combination with ketamine in the hippocampus. Superoxide dismutase (SOD) was increased by ECT and maintained by fluoxetine and bupropion in the PFC. ECT alone increased interleukin-1β (IL-1β) and the administration of ketamine was able to revert this increase showing a neuroprotective effect of this drug when in combination with ECT.

CONCLUSION

The treatment with ECT leads to an increase in oxidative damage and alters the immunological system. The combination with ketamine was able to protect against oxidative damage and the immunological response induced by ECT.

Psychedelics in Psychiatry: Neuroplastic, Immunomodulatory, and Neurotransmitter Mechanisms

Mounting evidence suggests safety and efficacy of psychedelic compounds as potential novel therapeutics in psychiatry. Ketamine has been approved by the Food and Drug Administration in a new class of antidepressants, and 3,4-methylenedioxymethamphetamine (MDMA) is undergoing phase III clinical trials for post-traumatic stress disorder. Psilocybin and lysergic acid diethylamide (LSD) are being investigated in several phase II and phase I clinical trials. Hence, the concept of psychedelics as therapeutics may be incorporated into modern society. Here, we discuss the main known neurobiological therapeutic mechanisms of psychedelics, which are thought to be mediated by the effects of these compounds on the serotonergic (via 5-HT2A and 5-HT1A receptors) and glutamatergic [via N-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors] systems. We focus on 1) neuroplasticity mediated by the modulation of mammalian target of rapamycin-, brain-derived neurotrophic factor-, and early growth response-related pathways; 2) immunomodulation via effects on the hypothalamic-pituitary-adrenal axis, nuclear factor ĸB, and cytokines such as tumor necrosis factor-α and interleukin 1, 6, and 10 production and release; and 3) modulation of serotonergic, dopaminergic, glutamatergic, GABAergic, and norepinephrinergic receptors, transporters, and turnover systems. We discuss arising concerns and ways to assess potential neurobiological changes, dependence, and immunosuppression. Although larger cohorts are required to corroborate preliminary findings, the results obtained so far are promising and represent a critical opportunity for improvement of pharmacotherapies in psychiatry, an area that has seen limited therapeutic advancement in the last 20 years. Studies are underway that are trying to decouple the psychedelic effects from the therapeutic effects of these compounds. SIGNIFICANCE STATEMENT: Psychedelic compounds are emerging as potential novel therapeutics in psychiatry. However, understanding of molecular mechanisms mediating improvement remains limited. This paper reviews the available evidence concerning the effects of psychedelic compounds on pathways that modulate neuroplasticity, immunity, and neurotransmitter systems. This work aims to be a reference for psychiatrists who may soon be faced with the possibility of prescribing psychedelic compounds as medications, helping them assess which compound(s) and regimen could be most useful for decreasing specific psychiatric symptoms.

Challenges and pitfalls in anesthesia for electroconvulsive therapy

Electroconvulsive therapy (ECT) refers to the application of electricity to the patients' scalp to treat psychiatric disorders, most notably, treatment-resistant depression. It is a safe, effective, and evidence-based therapy that is performed with general anesthesia. Muscle relaxation is used to prevent injuries related to the tonic-clonic seizure caused by ECT. Hypnotics are administered to induce amnesia and unconsciousness, so that, patients do not experience the period of muscle relaxation, while the generalized seizure is left unnoticed. For the anesthesiologist, ECT is associated with the challenges and pitfalls that are related to informed consent, social acceptance of ECT, airway management (especially in COVID-19 patients), and the interaction between ventilation and anesthetics from one viewpoint, and seizure induction and maintenance from another. The exact mode of action of the therapy is as unknown as the optimal choice or combination of anesthetics used.

Effectiveness and Safety of Ketamine for Unipolar Depression: a Systematic Review

Major Depressive Disorder (MDD) is a common psychiatric disorder with major implications for healthcare system and socioeconomic burden. For chronic and treatment-resistant depression, Ketamine has emerged as a possible treatment option. This systematic review explores the evidence for the effectiveness and tolerability of Ketamine in patients with MDD. This systematic review was conducted following the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) checklist. Eight electronic databases were searched by using search terms: (ketamine) AND (trial OR RCT OR clinical-trial) AND (depressive OR depression OR "depressive-disorder"). After a rigorous screening process against the predetermined eligibility criteria, 35 randomized controlled trials (RCTs) were included. Quality assessment of included studies was done by using the Cochrane risk-of-bias tool for RCTs. Thirty-five RCTs are included in this review article with majority of studies from United States, Iran, and China. Intravenous (IV) Ketamine was effective in 70% (21/30) of the included studies whereas oral and Intranasal (IN) Ketamine were effective in two and three studies, respectively. The majority of studies (6/8) using Ketamine as anesthetic agent during electroconvulsive therapy (ECT) failed to show an improvement compared to the participants receiving ECT and placebo. The most common reported side effects were nausea, vomiting, dizziness, diplopia, drowsiness, dysphoria, hallucinations, and confusion. Ketamine is an effective treatment option for patients with MDD with undesirable effects when administered via oral, IV and IN routes. Ketamine agumentation of ECT requires further exploration in well-designed studies with adequate sample size. The short-lived antidepressant effect of Ketamine is a potential limitation, therefore, further studies administering multiple infusions for acute treatment and maintenance are necessary.

Ketamine-induced changes in plasma brain-derived neurotrophic factor (BDNF) levels are associated with the resting-state functional connectivity of the prefrontal cortex

OBJECTIVES

Synaptic plasticity and brain-derived neurotrophic factor (BDNF) signalling are proposed to play key roles in antidepressant drug action. Ketamine, an N-methyl-D-aspartate receptor antagonist and putative antidepressant, may increase synaptic plasticity in prefrontal cortex through higher expression of BDNF. Furthermore, ketamine was shown to change resting-state functional connectivity (RSFC) of dorsomedial prefrontal cortex (dmPFC).

METHODS

In a randomised, placebo-controlled study, we investigated acutely (100 min) and at 24 h following subanesthetic ketamine infusion which dmPFC seeded RSFC changes are most strongly associated with plasma BDNF level changes in 53 healthy participants (21 females, age: 24.4 ± 2.9 years) using 7 T-fMRI.

RESULTS

We observed higher relative levels of BDNF 2 h and 24 h after ketamine compared to placebo. Whole-brain regression revealed that the change in BDNF after 24 h was associated with RSFC decreases from dmPFC to posterior cingulate cortex and ventromedial PFC at 24 h and exploratively also at the 100 min measurement point. Follow-up analyses revealed that RSFC reductions following ketamine were restricted to subjects showing increased BDNF levels at 24 h.

CONCLUSIONS

Our findings indicate BDNF level dynamics following ketamine are related to acute and 24 h RSFC changes. Particularly when BDNF increases are observed after ketamine infusion, a disconnection from dmPFC after 24 h is seen and may reflect synaptic plasticity effects.

Effects of Ketamine Anesthesia on Efficacy, Tolerability, Seizure Response, and Neurocognitive Outcomes in Electroconvulsive Therapy: A Comprehensive Meta-analysis of Double-Blind Randomized Controlled Trials

Electroconvulsive therapy (ECT) remains the most effective treatment for major depressive disorder. Ketamine is an anesthetic gaining attention for its rapid antidepressant effect. Numerous randomized controlled trials have investigated the effect of ketamine anesthesia in ECT on various clinical outcomes. Previous systematic reviews have not found benefit for overall depression response, although some have found evidence of benefit early in the ECT course. Clear quantitative conclusions have not been established regarding other outcomes, particularly while only using data from high-quality studies. We aimed to examine all data from double-blind randomized controlled trials comparing ketamine to other anesthetics via meta-analysis, to make recommendations regarding ECT practice and future research. Data were extracted for depressive symptoms, seizure duration and electrical dose, neuropsychological performance, and adverse effects. Effect sizes were calculated using Hedge's g and odds ratios. Eighteen studies (n = 915) were included in the meta-analysis. Ketamine was not found to enhance improvement of depressive symptoms, either early in ECT course or at end of study. Ketamine had a large effect on increasing seizure duration both overall (Hedge's g = 0.71, P = 0.038) and in the subgroup receiving ketamine in combination with another anesthetic (Hedge's g = 0.78, P < 0.01), and on decreasing electrical dose (Hedge's g = 1.98, P = 0.039). There was no significant effect of ketamine on any individual neuropsychological domain. Ketamine was not associated with increased adverse effects, except for hypertension in patients receiving ketamine monotherapy. Significant heterogeneity was present for many outcomes, and sensitivity analyses suggested a relation to methodological variation in most cases. This study supports the finding that ketamine does not enhance ECT's antidepressant effect, including on early improvement, but provides substantial evidence for enhancing seizure duration and reducing electrical dose. No significant benefit was found on neurocognitive outcomes, but analysis was limited by small sample sizes and high heterogeneity. Ketamine is generally safe in ECT, particularly as a coanesthetic. Our findings provide meta-analytic support to the recommendations in ECT clinical guidelines for use of coadjuvant ketamine in ECT where seizures are suboptimal. Further studies targeting neurocognitive outcomes are encouraged.

Frequency and Duration of Course of ECT Sessions: An Appraisal of Recent Evidence

AIMS AND METHOD

This paper aims to review the recent literature regarding factors influencing the frequency and number of sessions during a course of electroconvulsive therapy (ECT) for different psychiatric disorders. We systematically reviewed English-language papers of clinical trials of ECT published since the year 2000 in terms of frequency and number of sessions of ECT.

RESULTS

None of the 30 studies meeting our inclusion criteria were specifically designed to study frequency or number of sessions of ECT. A preliminary inference may be drawn regarding the number of sessions from the information available in these papers. For depression, patients receiving brief-pulse ECT needed fewer sessions than those receiving ultra-brief ECT when these were delivered at 8-times the threshold with unilateral electrode placement or at 2.5-times the threshold with bilateral placement. For schizophrenia, those receiving bifrontal ECT and ECT at 4-times the threshold-level stimulus needed fewer sessions than those receiving bitemporal ECT and 2-times the threshold-level stimulus, respectively. There were no clinical trials of the frequency of ECT sessions.

CLINICAL IMPLICATIONS

As there is a dearth of studies specifically examining frequency and number of ECT sessions, broad recommendations from professional bodies should continue to guide practice.

Ketamine plus propofol-electroconvulsive therapy (ECT) transiently improves the antidepressant effects and the associated brain functional alterations in patients with propofol-ECT-resistant depression

New methods for using ketamine in patients with propofol-electroconvulsive therapy-resistant depression (ECT-RD) are needed in the clinic. This study aimed to investigate the therapeutic efficacy of ketamine plus ECT in ECT-RD patients, along with the treatment-induced brain alterations. A total of 28 ECT-RD patients were intravenously injected with ketamine six times and treated with propofol-ECT six times alternately within two weeks. The Hamilton Depression Scale was used to assess the treatment effect. Global functional connectivity density (gFCD) and functional connectivity strength (FCS) were used to evaluate functional brain alterations. As compared with the propofol-ECT treatment group, the addition of ketamine could improve the therapeutic outcomes in patients with ECT-RD. The treatment increased gFCD in the left temporal and subgenual anterior cingulated cortex. Simultaneously, the treatment decreased FCS within the default mode network. Although increased functional connectivity could be sustained for 10 days, the clinical effect was only sustained 7 days, indicating that the clinical effect and functional brain alterations were disjointed. Ketamine plus propofol-ECT can obviously improve the effects of propofol-ECT in ECT-RD patients. However, the effect is limited in 7 days, suggesting the benefit is short-term.

Ketamine and nitrous oxide: The evolution of NMDA receptor antagonists as antidepressant agents

N-methyl-d-aspartate receptor (NMDAR) antagonists, including ketamine and nitrous oxide, are currently intensely studied as rapid-acting antidepressant agents. Interestingly, both of these compounds are also drugs of abuse. Intravenous ketamine, a dissociative anesthetic that induces complex downstream effects via NMDARs, rapidly reduces depressive and suicidal symptoms in treatment-resistant depression (TRD), as demonstrated by several trials. Recently, the United States Food and Drug Administration (FDA) approved an intranasal version of ketamine (esketamine) for TRD. The United States Drug Enforcement Agency (DEA) lists ketamine as a Class III scheduled drug (moderate-low potential for physical and psychological abuse). The FDA has established a Risk Evaluation and Management Strategy (REMS) program to ensure proper drug storage, handling, dispensing, and monitoring intranasal esketamine to minimize misuse/abuse opportunities. Nitrous Oxide is a colorless, odorless, gas that has been in medical use for over 150 years. The mechanisms of action of nitrous oxide are not fully understood; however, it is known to act as a non-competitive inhibitor of NMDA-type glutamate receptors. Currently, nitrous oxide is used for inhalational general anesthesia and analgesia for short procedures. Inhaled nitrous oxide is also used recreationally, primarily by teens and young adults, but is not believed to have strong addiction potential. In contrast to ketamine, nitrous oxide is not a controlled substance and can be legally purchased without a prescription. A recent double-blind, prospective, cross-over study demonstrated that nitrous oxide reduced depressive symptoms in a group of severely ill TRD patients. Though this is a promising initial study, further investigation is needed.

Antidepressant-Like Effects and Cognitive Enhancement of Coadministration of Chaihu Shugan San and Fluoxetine: Dependent on the BDNF-ERK-CREB Signaling Pathway in the Hippocampus and Frontal Cortex

Background

Fluoxetine (FLU) is the first-line and widely used medication for depression; however, FLU treatment is almost ineffective in 30%-40% of patients with depression. In addition, there are some problems in FLU treatment, such as delayed efficacy, large side effects, and poor tolerance. Chaihu Shugan San (CSS) is a classic and effective antidepressant Chinese herbal medicine that has been used in China for thousands of years. CSS or coadministration of CSS and FLU has become one of the most recommended methods in the treatment of depression in China. However, the specific pathways of CSS and coadministration of CSS and FLU for antidepressant are still unclear.

Objective

This study was designed to evaluate the antidepressant effects of CSS and coadministration of CSS and FLU.

Methods

The chronic unpredictable mild stress (CUMS) rat model was used to simulate depression. 120 healthy adult male Sprague-Dawley (SD) rats were randomly divided into seven groups: the control group, CUMS group, low-dose CSS group, high-dose CSS group, FLU group, coadministration of low-dose CSS and FLU group, and coadministration of high-dose CSS and FLU group. The rats in different groups were given different interventions. Then, the depression-like behavior and cognitive function were evaluated by the sucrose preference test (SPT), forced swimming test (FST), open field test (OFT), and Y-maze test. What is more, the antidepressant mechanism of CSS and coadministration of CSS and FLU were studied through BDNF mRNA, ERK mRNA, CREB mRNA, BDNF, p-ERK/ERK, and p-CREB/CREB levels in the hippocampus and frontal cortex by Western blot and RT-PCR.

Results

Compared with the CUMS group, CSS and coadministration of CSS and FLU could alleviate the depressive symptoms and improve cognitive function in CUMS rats (p < 0.05); CSS and coadministration of CSS and FLU could increase the expression of BDNF, p-CREB/CREB, p-ERK/ERK, and BDNF mRNA, CREB mRNA, and ERK mRNA in the hippocampus and frontal cortex (p < 0.05); CSS and coadministration of CSS and FLU could increase the expression of BDNF, p-CREB/CREB, p-ERK/ERK, and BDNF mRNA, CREB mRNA, and ERK mRNA in the hippocampus and frontal cortex (p < 0.05); CSS and coadministration of CSS and FLU could increase the expression of BDNF, p-CREB/CREB, p-ERK/ERK, and BDNF mRNA, CREB mRNA, and ERK mRNA in the hippocampus and frontal cortex (Discussion and Conclusion. Finally, we found that both CSS and coadministration of CSS and FLU play an antidepressant role, which may be due to the regulation of the BDNF/ERK/CREB signaling pathway in the hippocampus and frontal cortex. Among them, the coadministration of CSS and FLU can enhance the antidepressant effect of CSS or FLU alone, and the underlying mechanism needs further investigation.

Factors Associated With Delirium Following Electroconvulsive Therapy: A Systematic Review

OBJECTIVES

Delirium following electroconvulsive therapy (ECT) has been a clinical challenge, which, however, has not been investigated through a systematic literature review. The objective of this study was to systematically synthesize available evidence regarding factors associated with post-ECT delirium.

METHODS

We conducted a systematic literature search for any type of original investigations that reported risk factors of post-ECT delirium, using PubMed.

RESULTS

The literature search identified 43 relevant articles. One study found an association between catatonic feature and increased risk of postictal delirium. Five studies reported that the presence of cerebrovascular disease, Parkinson disease, or dementia was related to higher incidence of post-ECT delirium. Incidence of post-ECT course delirium was increased with bitemporal stimulation (3 studies). One study showed that ultrabrief pulse ECT reduced reorientation time following seizure compared with brief pulse ECT. High stimulus intensity resulted in more prolonged reorientation time after ECT than lower stimulus intensity (2 studies). Longer seizure length was significantly associated with post-ECT delirium in 1 study. Eight studies that examined postictal delirium in association with medications used, including lithium, did not show any consistent finding in their relationships. Four studies showed decreased incidence of postictal delirium in those receiving dexmedetomidine.

CONCLUSIONS

Limited evidence suggests that catatonic feature, cerebrovascular disease, Parkinson disease, dementia, bitemporal electrode placement, high stimulus intensity, or longer seizure length are associated with an increased risk of post-ECT delirium. Moreover, dexmedetomidine and ultrabrief pulse ECT seem to have preventive effects of post-ECT delirium.

Intermittent administration of low dose ketamine can shorten the course of electroconvulsive therapy for depression and reduce complications: A randomized controlled trial

This study aimed to investigate the efficacy and safety of intermittent low-dose ketamine on improving the efficacy of ECT. Patients diagnosed with Major Depressive Disorder (MDD) (n = 134) were randomized into 3 groups: routine ECT group (group E, n = 45); repeated ketamine-assisted ECT group (group RK, n = 43), and intermittent ketamine-assisted ECT group (group IK, n = 46). Patients in group RK were given ketamine at the dose of 0.3 mg/kg for each ECT treatment, patients in group IK were given ketamine once a week during ECT course. The depressive symptoms were assessed using the Hamilton Depression Rating Scale (HAM-D) at baseline, the end of ECT course, after 1 and 3 months, followed by an analysis of the psychiatric complications. Results indicated that ketamine-assisted ECT achieved a higher remission rate (P < 0.05), and no difference was observed between repeated and intermittent ketamine administrations. The total incidence rate of psychiatric complications in group RK (20.93%) was higher than that in group E (0%) and group IK (4.35%). In conclusion, intermittent administration of low dose ketamine in ECT significantly improved the effects of ECT and decreased psychiatric complications compared with repeated ketamine addition.

Ketamine and depression: a narrative review

Depression is the third leading cause of disability in the world. Depressive symptoms may be reduced within several weeks after the start of conventional antidepressants, but treatment resistance concerns one-third of patients who fail to achieve recovery. Over the last 20 years, ketamine, an antagonist of the N-methyl-D-aspartate receptor, has been described to have antidepressant properties. A literature review was conducted through an exhaustive electronic search. It was restricted to Cochrane reviews, meta-analyses, and randomized controlled trials (RCTs) of ketamine for major depressive disorder and/or bipolar disorder. This review included two Cochrane reviews, 14 meta-analyses and 15 trials. Ketamine was studied versus placebo, versus other comparators and as an anesthetic adjuvant before electroconvulsive therapy. In 14 publications, ketamine provided a rapid antidepressant effect with a maximum efficacy reached at 24 hrs. Its effect lasted for 1–2 weeks after infusion, but a longer-term effect is little reported. Ketamine does not seem to improve depressive symptoms at the end of electroconvulsive sessions. Safety and tolerability profiles with ketamine at low single dose are generally good in depressed patients. However, there is a lack of data concerning ketamine with repeated administration at higher doses. The clinical use of ketamine is increasing. Intranasal (S)-ketamine has recently been approved for depression by the Food and Drug Administration. It could be a promising treatment in depressed patients with suicidal ideation. Collectively, the level of proof of efficacy remains low and more RCTs are needed to explore efficacy and safety issues of ketamine in depression.

Adjunctive ketamine and electroconvulsive therapy for major depressive disorder: A meta-analysis of randomized controlled trials

BACKGROUND

Adjunctive ketamine with electroconvulsive therapy (ECT) has been investigated for treating major depressive disorder (MDD), but the findings have been inconsistent.

AIM

This is an updated meta-analysis of the efficacy and safety of ketamine augmentation of ECT in the treatment of MDD.

METHODS

Randomized controlled trials (RCTs) reporting on the efficacy and safety of ketamine and ECT were identified and analyzed.

RESULTS

Seventeen RCTs (n = 1,035) compared ketamine alone or ketamine plus other anesthetic drugs (n = 557) with other anesthetic agents (n = 478) in MDD patients who received ECT. Ketamine+other anesthetic drugs was superior in improving depressive symptoms over other anesthetic medications at early study time point, but not at post-ECT or end of study time points. Ketamine alone was not more efficacious in treating depressive symptoms than other anesthetic drugs at early study, post-ECT and end of study time points. Sensitivity analysis and 19 of the 20 subgroup analyses also confirmed the lack of significance of these findings. Eleven RCTs testing the effects of ketamine on neurocognitive functions with various test batteries found mixed results. Ketamine alone significantly increased blood pressure more than other anesthetic drugs in MDD treated with ECT.

CONCLUSION

Compared to other anesthetic agents, ketamine alone does not appear to improve the efficacy of ECT. However, ketamine+other anesthetic combinations may confer a short-term advantage in improving depressive symptom at the early stages of ECT.

Neuroanesthesiology Update

This review provides a summary of the literature pertaining to the perioperative care of neurosurgical patients and patients with neurological diseases. General topics addressed in this review include general neurosurgical considerations, stroke, traumatic brain injury, neuromonitoring, neurotoxicity, and perioperative disorders of cognitive function.