Effects of Electroconvulsive Therapy on Depression and Its Potential Mechanism

Leveraging DNA methylation to predict treatment response in major depressive disorder: A critical review

Major depressive disorder (MDD) is a debilitating and prevalent mental disorder with a high disease burden. Despite a wide array of different treatment options, many patients do not respond to initial treatment attempts. Selection of the most appropriate treatment remains a significant clinical challenge in psychiatry, highlighting the need for the development of biomarkers with predictive utility. Recently, the epigenetic modification DNA methylation (DNAm) has emerged to be of great interest as a potential predictor of MDD treatment outcomes. Here, we review efforts to date that seek to identify DNAm signatures associated with treatment response in individuals with MDD. Searches were conducted in the databases PubMed, Scopus, and Web of Science with the concepts and keywords MDD, DNAm, antidepressants, psychotherapy, cognitive behavior therapy, electroconvulsive therapy, transcranial magnetic stimulation, and brain stimulation therapies. We identified 32 studies implicating DNAm patterns associated with MDD treatment outcomes. The majority of studies (N = 25) are focused on selected target genes exploring treatment outcomes in pharmacological treatments (N = 22) with a few studies assessing treatment response to electroconvulsive therapy (N = 3). Additionally, there are few genome-scale efforts (N = 7) to characterize DNAm patterns associated with treatment outcomes. There is a relative dearth of studies investigating DNAm patterns in relation to psychotherapy, electroconvulsive therapy, or transcranial magnetic stimulation; importantly, most existing studies have limited sample sizes. Given the heterogeneity in both methods and results of studies to date, there is a need for additional studies before existing findings can inform clinical decisions.

Multiomics and blood-based biomarkers of electroconvulsive therapy in severe and treatment-resistant depression: study protocol of the DetECT study

Electroconvulsive therapy (ECT) is commonly used to treat treatment-resistant depression (TRD). However, our knowledge of the ECT-induced molecular mechanisms causing clinical improvement is limited. To address this issue, we developed the single-center, prospective observational DetECT study ("Multimodal Biomarkers of ECT in TRD"; registered 18/07/2022, www.clinicalTrials.gov , NCT05463562). Its objective is to identify molecular, psychological, socioeconomic, and clinical biomarkers of ECT response in TRD. We aim to recruit n = 134 patients in 3 years. Over the course of 12 biweekly ECT sessions (± 7 weeks), participant blood is collected before and 1 h after the first and seventh ECT and within 1 week after the twelfth session. In pilot subjects (first n = 10), additional blood draws are performed 3 and 6 h after the first ECT session to determine the optimal post-ECT blood draw interval. In blood samples, multiomic analyses are performed focusing on genotyping, epigenetics, RNA sequencing, neuron-derived exosomes, purines, and immunometabolics. To determine clinical response and side effects, participants are asked weekly to complete four standardized self-rating questionnaires on depressive and somatic symptoms. Additionally, clinician ratings are obtained three times (weeks 1, 4, and 7) within structured clinical interviews. Medical and sociodemographic data are extracted from patient records. The multimodal data collected are used to perform the conventional statistics as well as mixed linear modeling to identify clusters that link biobehavioural measures to ECT response. The DetECT study can provide important insight into the complex mechanisms of ECT in TRD and a step toward biologically informed and data-driven-based ECT biomarkers.

Receipt of Electroconvulsive Therapy in Outpatient Settings in a National Sample of Privately Insured Patients With Mood Disorders

PURPOSE

Electroconvulsive therapy (ECT), an effective treatment for bipolar and major depressive disorder, is underused. Little information is available on use of ECT in potentially less costly outpatient settings, possibly reducing cost barriers.

METHODS

Insurance claims from the 2008 to 2017 MarketScan Commercial Database for patients diagnosed with mood disorders were used to compare 4 groups of ECT users in each year: those receiving (1) exclusively outpatient ECT, (2) first inpatient and subsequently outpatient, (3) outpatient and subsequently inpatient, and (4) exclusively inpatient ECT. Groups were compared on the proportion receiving ECT in each group over time as well as on the total numbers of treatments received along with group differences in sociodemographic and diagnostic characteristics and health care costs.

RESULTS

Among 2.9 million patients diagnosed with mood disorders, the proportion who received ECT (n = 8859) was small (0.30%) and declined over the decade to 0.17%. Among those who received ECT, most did so exclusively as outpatients (52.3%), the group with fewest comorbidities and lowest costs. This proportion increased by 19.7% over the decade, whereas the proportion receiving ECT exclusively in an inpatient setting (12.1%) fell by 30.6%. The total number of treatments per patient averaged 11.7 per year and increased by 28.0% over the decade, with outpatients decreasing to slightly less than average. Health care costs were greatest for those who started ECT as inpatients.

CONCLUSIONS

Although the proportion of privately insured patients receiving ECT in outpatient settings has increased, reducing cost barriers, the use of ECT continued to be extremely limited and declining.

Novel rapid treatment options for adolescent depression

There is an urgent need for novel fast-acting antidepressants for adolescent treatment-resistant depression and/or suicidal risk, since the selective serotonin reuptake inhibitors that are clinically approved for that age (i.e., fluoxetine or escitalopram) take weeks to work. In this context, one of the main research lines of our group is to characterize at the preclinical level novel approaches for rapid-acting antidepressants for adolescence. The present review summarizes the potential use in adolescence of non-pharmacological options, such as neuromodulators (electroconvulsive therapy and other innovative types of brain stimulation), as well as pharmacological options, including consciousness-altering drugs (mainly ketamine but also classical psychedelics) and cannabinoids (i.e., cannabidiol), with promising fast-acting responses. Following a brief analytical explanation of adolescent depression, we present a general introduction for each therapeutical approach together with the clinical evidence supporting its potential beneficial use in adolescence (mainly extrapolated from prior successful examples for adults), to then report recent and/or ongoing preclinical studies that will aid in improving the inclusion of these therapies in the clinic, by considering potential sex-, age-, and dose-related differences, and/or other factors that might affect efficacy or long-term safety. Finally, we conclude the review by providing future avenues to maximize treatment response, including the need for more clinical studies and the importance of designing and/or testing novel treatment options that are safe and fast-acting for adolescent depression.

Efficacy and acceptability of psilocybin for primary or secondary depression: A systematic review and meta-analysis of randomized controlled trials

Introduction

Psilocybin is a classic psychedelics, which has been shown to have antidepressant effects by many studies in recent years. In this study, we aim to evaluate the efficacy, acceptability and tolerability of psilocybin in the treatment of primary (major depressive disorder) or secondary (experiencing distress related to life-threatening diagnoses and terminal illness) depression.

Methods

We searched PubMed, EMBASE, Web of Science, Cochrane Library and ClinicalTrials.gov for clinical trials of psilocybin for depression (updated to 4 October, 2023). Effect size Hedges' g was used as an indicator of efficacy, and other outcomes included response rate, drop-out rate, and adverse events.

Results

A total of 10 studies were finally included in systematic review. 8 studies were included in the meta-analysis, involving a total of 524 adult patients, and produced a large effect size in favor of psilocybin (Hedge's g =-0.89, 95% CI -1.25~-0.53, I² = 70.19%, P<0.01). The therapeutic effects of psilocybin increase with increasing doses. Adverse events caused by psilocybin are generally transient and reversible, but serious adverse events also may occur.

Discussion

Our study shows that psilocybin has both short-term and long-term antidepressant effects and holds promise as a potential complementary or alternative therapy for depression, probably. Further research may reveal more about its therapeutic potential.

Neural correlates of episodic memory decline following electroconvulsive therapy: An exploratory functional magnetic resonance imaging study

BACKGROUND

Electroconvulsive therapy (ECT) is an efficient and rapid-acting treatment indicated for severe depressive disorders. While ECT is commonly accompanied by transient memory decline, the brain mechanisms underlying these side effects remain unclear.

AIMS

In this exploratory functional magnetic resonance (fMRI) study, we aimed to compare effects of ECT versus pharmacological treatment on neural response during episodic memory encoding in patients with affective disorders.

METHODS

This study included 32 ECT-treated patients (major depressive disorder (MDD), n = 23; bipolar depression, n = 9) and 40 partially remitted patients in pharmacological treatment (MDD, n = 24; bipolar disorder, n = 16). Participants underwent neuropsychological assessment, a strategic picture encoding fMRI scan paradigm, and mood rating. The ECT group was assessed before ECT (pre-ECT) and 3 days after their eighth ECT session (post-ECT).

RESULTS

Groups were comparable on age, gender, and educational years (ps ⩾ 0.05). Within-group analyses revealed a selective reduction in verbal learning and episodic memory pre- to post-ECT (p = 0.012) but no decline in global cognitive performance (p = 0.3). Functional magnetic resonance imaging analyses adjusted for mood symptoms revealed greater activity in ECT-treated patients than pharmacologically treated No-ECT patients across left precentral gyrus (PCG), right dorsomedial prefrontal cortex (dmPFC), and left middle frontal gyrus (MFG). In ECT-treated patients, greater decline in verbal learning and memory performance from pre- to post-ECT correlated with higher PCG response (r = -0.46, p = 0.008), but not with dmPFC or MFG activity (ps ⩾ 0.1), post-ECT.

CONCLUSIONS

Episodic memory decline was related to greater neural activity in the left PCG, but unrelated to increased dmPFC and MFG activity, immediately after ECT.

Converged avenues: depression and Alzheimer's disease- shared pathophysiology and novel therapeutics

Depression, a highly prevalent disorder affecting over 280 million people worldwide, is comorbid with many neurological disorders, particularly Alzheimer's disease (AD). Depression and AD share overlapping pathophysiology, and the search for accountable biological substrates made it an essential and intriguing field of research. The paper outlines the neurobiological pathways coinciding with depression and AD, including neurotrophin signalling, the hypothalamic-pituitary-adrenal axis (HPA), cellular apoptosis, neuroinflammation, and other aetiological factors. Understanding overlapping pathways is crucial in identifying common pathophysiological substrates that can be targeted for effective management of disease state. Antidepressants, particularly monoaminergic drugs (first-line therapy), are shown to have modest or no clinical benefits. Regardless of the ineffectiveness of conventional antidepressants, these drugs remain the mainstay for treating depressive symptoms in AD. To overcome the ineffectiveness of traditional pharmacological agents in treating comorbid conditions, a novel therapeutic class has been discussed in the paper. This includes neurotransmitter modulators, glutamatergic system modulators, mitochondrial modulators, antioxidant agents, HPA axis targeted therapy, inflammatory system targeted therapy, neurogenesis targeted therapy, repurposed anti-diabetic agents, and others. The primary clinical challenge is the development of therapeutic agents and the effective diagnosis of the comorbid condition for which no specific diagnosable scale is present. Hence, introducing Artificial Intelligence (AI) into the healthcare system is revolutionary. AI implemented with interdisciplinary strategies (neuroimaging, EEG, molecular biomarkers) bound to have accurate clinical interpretation of symptoms. Moreover, AI has the potential to forecast neurodegenerative and psychiatric illness much in advance before visible/observable clinical symptoms get precipitated.

Targeting metaplasticity mechanisms to promote sustained antidepressant actions

The discovery that subanesthetic doses of (R, S)-ketamine (ketamine) and (S)-ketamine (esketamine) rapidly induce antidepressant effects and promote sustained actions following drug clearance in depressed patients who are treatment-resistant to other therapies has resulted in a paradigm shift in the conceptualization of how rapidly and effectively depression can be treated. Consequently, the mechanism(s) that next generation antidepressants may engage to improve pathophysiology and resultant symptomology are being reconceptualized. Impaired excitatory glutamatergic synapses in mood-regulating circuits are likely a substantial contributor to the pathophysiology of depression. Metaplasticity is the process of regulating future capacity for plasticity by priming neurons with a stimulation that alters later neuronal plasticity responses. Accordingly, the development of treatment modalities that specifically modulate the duration, direction, or magnitude of glutamatergic synaptic plasticity events such as long-term potentiation (LTP), defined here as metaplastogens, may be an effective approach to reverse the pathophysiology underlying depression and improve depression symptoms. We review evidence that the initiating mechanisms of pharmacologically diverse rapid-acting antidepressants (i.e., ketamine mimetics) converge on consistent downstream molecular mediators that facilitate the expression/maintenance of increased synaptic strength and resultant persisting antidepressant effects. Specifically, while the initiating mechanisms of these therapies may differ (e.g., cell type-specificity, N-methyl-D-aspartate receptor (NMDAR) subtype-selective inhibition vs activation, metabotropic glutamate receptor 2/3 antagonism, AMPA receptor potentiation, 5-HT receptor-activating psychedelics, etc.), the sustained therapeutic mechanisms of putative rapid-acting antidepressants will be mediated, in part, by metaplastic effects that converge on consistent molecular mediators to enhance excitatory neurotransmission and altered capacity for synaptic plasticity. We conclude that the convergence of these therapeutic mechanisms provides the opportunity for metaplasticity processes to be harnessed as a druggable plasticity mechanism by next-generation therapeutics. Further, targeting metaplastic mechanisms presents therapeutic advantages including decreased dosing frequency and associated diminished adverse responses by eliminating the requirement for the drug to be continuously present.

Augmentation of Electroconvulsive Therapy with Oral Caffeine: A Retrospective Analysis of 40 Patients with Major Depression

OBJECTIVE

Studies have demonstrated the efficacy of injectable caffeine as an augmentation method in electroconvulsive therapy (ECT). This study investigated whether orally administered caffeine increases seizure duration during ECT.

METHODS

Medical records of 40 patients treated with a series of ECT were retrospectively analyzed. Patients whose electroencephalogram (EEG) seizure duration had dropped<30 s, or motor seizure duration<15 s were included. They subsequently received oral caffeine (0.2 g) before ECT sessions. Primary outcomes were EEG seizure duration and motor seizure duration, compared with those from the last pre-caffeine session (baseline) and the first five caffeine-augmented sessions. The mental state was assessed with the Global Assessment of Functioning (GAF). In addition, data on maximum heart rate, maximal arterial pressure, and adverse effects were collected.

RESULTS

The EEG seizure duration increased by 14.9 s (52%) on average between baseline and the first caffeine-augmented session. The increased length remained widely stable over the subsequent ECT sessions. EEG seizure duration was>30 s in more than 80% of sessions. A statistically significant increase in motor seizure duration appeared only in the 2nd and 3rd of five sessions with augmentation. Oral caffeine pretreatment was overall well tolerated. The percentage of patients with at least serious mental impairment (GAF score≤50) dropped from 77.5 to 15%.

CONCLUSIONS

Results suggest the utility of oral caffeine (0.2 g) to increase ECT-induced seizures in patients with durations below clinically significant thresholds.

Importance of achieving rapid treatment response in major depressive disorder

Major depressive disorder (MDD) is a leading contributor to disability worldwide and is associated with increased morbidity and mortality. Current pharmacologic treatment options may be ineffective for some patients and can pose several limitations and challenges, including suboptimal response and slow onset of action. Many of these therapies can take 6 to 8 weeks for patients to achieve response and 12 weeks or longer to demonstrate full clinical benefit. Delays in depressive symptom resolution are associated with poor symptomatic and functional outcomes, decreased quality of life, and increased burden on the healthcare system. Achieving response and remission of symptoms soon after diagnosis and treatment is associated with lower rates of relapse and a greater likelihood of functional recovery. An unmet need exists for innovative treatments that offer rapid and sustained effects. This editorial discusses the benefits of rapid improvement in depressive symptoms with available and investigational agents for patients with MDD.

Whole Person Modeling: a transdisciplinary approach to mental health research

The growing global burden of mental illness has prompted calls for innovative research strategies. Theoretical models of mental health include complex contributions of biological, psychosocial, experiential, and other environmental influences. Accordingly, neuropsychiatric research has self-organized into largely isolated disciplines working to decode each individual contribution. However, research directly modeling objective biological measurements in combination with cognitive, psychological, demographic, or other environmental measurements is only now beginning to proliferate. This review aims to (1) to describe the landscape of modern mental health research and current movement towards integrative study, (2) to provide a concrete framework for quantitative integrative research, which we call Whole Person Modeling, (3) to explore existing and emerging techniques and methods used in Whole Person Modeling, and (4) to discuss our observations about the scarcity, potential value, and untested aspects of highly transdisciplinary research in general. Whole Person Modeling studies have the potential to provide a better understanding of multilevel phenomena, deliver more accurate diagnostic and prognostic tests to aid in clinical decision making, and test long standing theoretical models of mental illness. Some current barriers to progress include challenges with interdisciplinary communication and collaboration, systemic cultural barriers to transdisciplinary career paths, technical challenges in model specification, bias, and data harmonization, and gaps in transdisciplinary educational programs. We hope to ease anxiety in the field surrounding the often mysterious and intimidating world of transdisciplinary, data-driven mental health research and provide a useful orientation for students or highly specialized researchers who are new to this area.

Electroconvulsive therapy: recent advances and anesthetic considerations

PURPOSE OF REVIEW

This review summarizes the current indications and principles of ECT. Contemporary anesthetic considerations are described with a focus on the optimal use of hypnotic agents and providing ECT in pregnant patients.

RECENT FINDINGS

ECT is useful in treatment-resistant major depression, bipolar disorders, and treatment-resistant schizophrenia. It is a well tolerated treatment in pregnant patients with treatment-resistant depression. Cognitive side effects may be attenuated by using unilateral placement of scalp electrodes, fewer treatment sessions, and the use of ultrabrief pulse width of the electrical charge. All modern hypnotics can be used for induction of anesthesia for ECT but should be titrated to effect. Etomidate is superior to Propofol in regarding seizure quality. The use of Ketamine shows good seizure quality and may alleviate cognitive impairment. Providing ECT for pregnant patients may prove challenging because of logistic difficulties and the physiologic changes during pregnancy. Although representing an effective treatment option in severely ill patients, ECT is underutilized because of stigmatization and ethnic and financial disparities.

SUMMARY

ECT is effective in treating treatment-resistant psychiatric illnesses. Symptoms of cognitive impairment are the most common side effects but can be treated by modifying the technique of ECT. All modern hypnotics can be used for the induction of general anesthesia. Etomidate and Ketamine may be of special interest in patients with insufficient seizure duration. Treating pregnant patients with ECT requires a multidisciplinary approach, in order to provide a safe therapy for mother and unborn child. Stigmatization and social disparities are hindering the widespread use of ECT as an effective treatment for severely ill psychiatric patients.

Clozapine in Treatment-Resistant Schizophrenia and Its Augmentation with Electroconvulsive Therapy in Ultra-Treatment-Resistant Schizophrenia

Clozapine is considered the gold standard for patients with treatment-resistant schizophrenia (TRS) who have previously tried other antipsychotics at adequate doses (two or more, with at least one being atypical). However, despite optimal treatment, a subgroup of TRS patients with what is known as ultra-treatment-resistant schizophrenia (UTRS) fails to respond to clozapine, which occurs in 40–70% of cases. The most common approach to manage UTRS involves augmenting clozapine with pharmacological or non-pharmacological interventions, with a growing body of evidence that supports the use of electroconvulsive therapy (ECT) as an augmenter. This prospective non-randomized 8-week study, which followed the TRIPP Working Group guidelines and is one of few that separate TRS from UTRS, aimed to evaluate the effectiveness of clozapine in TRS patients and the efficacy of ECT augmentation of clozapine in UTRS patients. Patients with TRS were assigned to receive clozapine alone (clozapine group), whereas UTRS patients received bilateral ECT in addition to their current medication regimen (ECT plus clozapine group). The severity of symptoms was evaluated using the Clinical Global Impression Scale (CGI) and Positive and Negative Syndrome Scale (PANSS) at baseline and at the end of the 8-week trial. Both treatment approaches resulted in improved CGI and PANSS scores. The results suggest that both clozapine and ECT are effective treatment options for patients with TRS and UTRS, respectively, and that adherence to guidelines should provide a better frame for future clinical studies.

[Recent approaches to the diagnosis and therapy of monopolar depression]

Unipolar depression is one of the most significant biomedical problems, which is associated with its high prevalence, a pronounced negative impact on the level of work capacity of the population, worsening of the course of most somatic and neurological diseases, and suicide risk. This review presents current data on approaches to the diagnosis of monopolar depression, both classical (clinical and psychometric) and using modern technologies. The existing approaches to the therapy of monopolar depression - psychopharmacologic, psychotherapeutic, and non-drug biological approaches - are discussed. The advantages of the selective serotonin reuptake inhibitor sertraline are presented, and its use as a first-line drug is justified.

Challenges of treating catatonia in the community setting without access to electroconvulsive therapy

Catatonia is a psychomotor syndrome resulting from an underlying psychiatric or medical disorder commonly observed in inpatient psychiatric units. While benzodiazepines and electroconvulsive therapy (ECT) are effective treatment options, the unavailability of ECT in many community psychiatric hospitals in the United States negatively affects patient outcomes. We present a 25-year-old African American male with a psychiatric diagnosis of schizophrenia complicated by malignant catatonia who was admitted to a community psychiatric hospital. He required intensive medical stabilization with supportive management, and transfer requests to ECT-equipped hospitals were initiated. While awaiting transfer for 148 days, the patient's symptoms did not fully remit with lorazepam (even with 36 mg daily in divided doses) and other psychotropic medication trials, including antipsychotics and mood stabilizers. After nearly 5 months of inpatient stay, he was successfully transferred, received ECT treatment, and experienced rapid resolution of catatonia. After discharge, to obtain three monthly sessions of maintenance ECT, he had 5-h one-way ground transportation arranged to an out-of-county ECT-equipped facility. There was no relapse in catatonia by the 2-year follow-up. This report highlights a significant healthcare disparity when attempting to manage severe catatonia within community hospital settings without access to ECT in the United States. Alternative treatments, including antipsychotics, had minimal impact on symptoms and possibly increased morbidity in this case while awaiting ECT. Treatment at our designated safety net hospital still required referral to 14 ECT-equipped hospitals before successful transfer. This case highlights the urgent need for ECT availability in more community hospitals to treat patients with refractory psychiatric conditions, including catatonia. ECT is an essential psychiatric treatment that, for certain conditions, has no appropriate alternatives. We propose that access to ECT be considered in the determination of safety net hospital systems, with improved ability to transfer patients who are suffering from treatable life-threatening mental health conditions.

Electrical stimulus combined with venlafaxine and mirtazapine improves brain Ca2+ activity, pre-pulse inhibition, and immobility time in a model of major depressive disorder in schizophrenia

BACKGROUND

The prevalence of major depressive disorder in patients with schizophrenia (SZ-MDD) has been reported to be about 32.6 %, but it varies considerably depending on the stage (early or chronic) and state (acute or post-psychotic) of schizophrenia. The exploration of ideal strategies for the treatment of major depressive disorder in the context of schizophrenia is urgently needed. Thus, the present study was conducted to investigate the treatment effects of clozapine, electrical stimulation (ECS; the mouse model equivalent of electroconvulsive therapy for humans), venlafaxine, and mirtazapine for SZ-MDD.

METHODS

A mouse model of SZ-MDD was established with MK801 administration and chronic unpredictable mild stress exposure. Clozapine and ECS, alone and with mirtazapine and/or venlafaxine, were used as treatment strategies. In-vivo two-photon imaging was performed to visualize Ca²⁺ neural activity in the prefrontal cortex (PFC). Mouse performance on behavioral assays was taken to reflect acute treatment effects.

RESULTS

ECS + venlafaxine + mirtazapine performed significantly better than other treatments in alleviating major depressive disorder, as reflected by PFC Ca²⁺ activity and behavioral assay performance. Clozapine + venlafaxine + mirtazapine did not have an ideal treatment effect. Brain Ca²⁺ activity alterations did not correlate with behavioral expression in any treatment group.

CONCLUSIONS

In this mouse model of SZ-MDD, ECS + venlafaxine + mirtazapine improved brain Ca2+ activity, pre-pulse inhibition, and immobility time. These findings provide useful information for the further exploration of treatment methods for patients with SZ-MDD, although the mechanisms underlying this comorbidity needed to be investigated further.

Current Perspectives on Pharmacological and Non-Pharmacological Interventions for the Inflammatory Mechanism of Unipolar Depression

Since depression remains a major public health issue there is a constant need for new and more efficient therapeutic strategies based on the mechanisms involved in the aetiology of depression. Thus, the pathogenic link between depression and inflammation is considered to play a potential key role in the development of such therapies. This review summarizes the results of various pharmacological (non-steroidal anti-inflammatory drugs, aspirin, cyclooxygenase inhibitors, cytokine inhibitors, corticosteroids, statins, minocycline, N-acetyl cysteine, omega-3 fatty acids and probiotics) and non-pharmacological interventions (electroconvulsive therapy, physical exercise and psychological therapy) and outlines their efficacy and discusses potential challenges. Both conventional and non-conventional anti-inflammatory drugs showed promising results according to the specific group of patients. The pre-existing pro-inflammatory status was, in most cases, a predictor for clinical efficacy and, in some cases, a correlation between clinical improvement and changes in various biomarkers was found. Some of the non-pharmacological interventions (physical exercise and electroconvulsive therapy) have also showed beneficial effects for depressive patients with elevated inflammatory markers. Treatments with anti-inflammatory action may improve clinical outcomes in depression, at least for some categories of patients, thus opening the way for a future personalised approach to patients with unipolar depression regarding the inflammation-related mechanism.

Dexmedetomidine Regulates the miR-146a-5p/NF-κB Axis to Alleviate Electroconvulsive Therapy-Induced Cognitive Impairments

Electroconvulsive therapy (ECT) is a nonpharmacological treatment for depressive episodes and other psychiatric disorders. It is used to control the condition by causing a transient loss of consciousness through electrical stimulation. Dexmedetomidine (DEX) is a novel and highly selective adrenergic agonist with sedative, sympathetic nerve activity inhibiting and stress-responsive effects. This study focused on the effect of DEX on cerebral protection after ECT treatment. 68 depression patients were enrolled and divided into control group and DEX group. The occurrence of delirium after ECT treatment in depression cases was recorded. In vivo, we constructed chronic mild and unpredictable stress (CUMS) rats to mimic depression model. Meanwhile, ECT treatment and DEX injection were administrated in CUMS rats. Learning and memory in rats were measured by Morris water maze test, open field test (OFT), and forced swimming test (FST). Finally, the expression of miR-146a-5p and NF-κB was determined by RT-qPCR and western blot assay. The incidence of delirium after ECT treatment was prominently reduced in DEX group in relation to control group. In vivo, DEX injection had no effect on ECT treatment efficacy against depression conditions. After ECT treatment, the cognitive impairment was ameliorated in CUMS rats accomplished with decreased miR-146a-5p and increased NF-κB level. Finally, compared with ECT treatment, DEX injection could protect against depression-like behaviors by increasing miR-146a-5p level and inactivated NF-κB pathway. Overall, ECT-induced cognitive impairment in depression rats could be ameliorated by DEX injection via miR-146a-5p/NF-κB axis.

Invisible wounds: Suturing the gap between the neurobiology, conventional and emerging therapies for posttraumatic stress disorder

A sharp increase in the prevalence of neuropsychiatric disorders, including major depression, anxiety, substance use disorders and posttraumatic stress disorder (PTSD) has occurred due to the traumatic nature of the persisting COVID-19 global pandemic. PTSD is estimated to occur in up to 25% of individuals following exposure to acute or chronic trauma, and the pandemic has inflicted both forms of trauma on much of the population through both direct physiological attack as well as an inherent upheaval to our sense of safety. However, despite significant advances in our ability to define and apprehend the effects of traumatic events, the neurobiology and neuroanatomical circuitry of PTSD, one of the most severe consequences of traumatic exposure, remains poorly understood. Furthermore, the current psychotherapies or pharmacological options for treatment have limited efficacy, durability, and low adherence rates. Consequently, there is a great need to better understand the neurobiology and neuroanatomy of PTSD and develop novel therapies that extend beyond the current limited treatments. This review summarizes the neurobiological and neuroanatomical underpinnings of PTSD and discusses the conventional and emerging psychotherapies, pharmacological and combined psychopharmacological therapies, including the use of psychedelic-assisted psychotherapies and neuromodulatory interventions, for the improved treatment of PTSD and the potential for their wider applications in other neuropsychiatric disorders resulting from traumatic exposure.

The anticholinergic burden is not associated with cognitive impairments in patients treated by electroconvulsive therapy for treatment-resistant depression

BACKGROUND

Electroconvulsive therapy (ECT) is the most effective non-pharmacological treatment for treatment-resistant depression (TRD) but can expose to transient cognitive impairments. Understanding factors underlying these cognitive side effects is important. This study investigated the impact of anticholinergic treatments on cognitive performances after ECT courses for TRD in naturalistic condition.

METHODS

Impact of anticholinergic burden (Anticholinergic Impregnation Scale, AIS) on cognitive changes (Montreal Cognitive Assessment, MoCA) adjusted on depression level (Montgomery and Asberg Depression Scale, MADRS) was investigated in 42 patients who received an ECT course between 2017 and 2020 for unipolar or bipolar TRD. Collection of daily treatments given during ECT was carried out via the computerized traceability of treatments validated by nurses.

RESULTS

Among the 31 treatments identified with an anticholinergic score, which represent only 38% of total treatments, the three most frequently given treatments were Lorazepam (47%), Venlafaxine (36%) and Cyamemazine (26%). Delayed recall was the most frequently impaired cognitive function after ECT courses. Using logistic regression, we found no association between the anticholinergic burden and the decrease in cognitive scores after ECT courses, adjusted on MADRS score evolution (p > 0.1). Conversely, improvement in MADRS scores were correlated with improvement in attention MoCA subscores.

LIMITATIONS

This is a retrospective monocentric study with a moderate sample size using anticholinergic scales to calculate the anticholinergic burden without plasma dosage.

CONCLUSION

Anticholinergic treatments did not seem to explain ECT-related cognitive impairments. This warrants further large prospective investigations including different measures of anticholinergic burden.

Rapid treatments for depression: Endocannabinoid system as a therapeutic target

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

Examining the correlation between treatment effects in clinical trials and economic modelling

INTRODUCTION

Many diseases have a sequential treatment pathway. Compared with patients without previous treatment, patients who fail initial treatment may have lower success rates with a second treatment. This phenomenon can be explained by a correlation between treatment effects.

METHODS

We developed a statistical model of covariance for the underlying unobserved correlation between treatments and established a mathematical expression for the magnitude of the latent correlation term. We conducted a simulation study of clinical trials to investigate the correlation between two treatments and explored clinical examples based on published literature to illustrate the identification and evaluation of these correlations.

RESULTS

Our simulation study confirmed that a treatment correlation reduces the probability of success for the second treatment, compared with no correlation. We found that treatment correlations may be observable in clinical trials, such as for depression and lung cancer, and the magnitude of correlation may be estimated. We illustrated that treatment correlations can be incorporated into an economic model, with possible impacts on cost-effectiveness results. Additional applications of correlation concepts are also discussed.

CONCLUSIONS

We evaluated the correlation between treatment effects and our approach can be applied to clinical trial design and economic modelling of sequential clinical treatment pathways.

Comparison of the Clinical and Treatment Characteristics of Patients Undergoing Electroconvulsive Therapy for Catatonia Indication in the Context of Gender

The aim of this study was to compare in the context of gender both clinical diagnosis and disease-related differences and electroconvulsive therapy (ECT)-related differences in data and efficacy in hospitalized patients with catatonic signs and symptoms. Data from 106 patients who received ECT with catatonia indication were retrospectively analyzed. Clinical data of male (n = 58) and female (n = 48) patients were compared. Hospitalization documents and outpatient files, sociodemographic and clinical data form, Clinical Global Improvement scores used by the ECT unit in the follow-up of patients who received ECT were used in the study. It was seen that the mean age of women at the onset of ECT was higher than in men and the presence of prolonged seizures was more common than men. In men, it was found out that the average number of sessions with the onset of clinical response to treatment was higher than the average of women. The distribution of diagnoses by gender showed that the presence of schizophrenia diagnosis in men and of bipolar disorder in women were significantly more frequent compared to the opposite sex. It was found out that there were no significant differences between genders in terms of response rate to ECT. Our study is important for being the first study in the literature investigating the gender differences in ECT used for catatonia. However, gender is not a distinctive factor in the effectiveness of treatment, there are some important differences between male and female patients showing signs and symptoms of catatonia and undergoing ECT.

Effectiveness of aromatherapy with inhaled lavender essential oil and breathing exercises on ECT-related anxiety in depressed patients

Background and aims Electroconvulsive therapy (ECT) is considered a safe, effective, and significant treatment in patients suffering from a major depressive disorder. Anxiety caused by this invasive treatment may impose several side effects on patients. The purpose of this study was to evaluate the effectiveness of aromatherapy with inhaled lavender essential oil and breathing exercises on ECT-related anxiety in depressed patients. Methods In this randomized controlled clinical trial, 90 depressed patients were selected and divided into three groups: aromatherapy, breathing exercise, and routine care using a random allocation method. Before undergoing ECT, the aromatherapy group was exposed to the inhaled lavender essential oil (n = 30), the breathing exercise group performed the breathing exercises (n = 30), and the routine care group received routine care (n = 30). Before (20 min) and after the intervention (30 min later), patients' anxiety was assessed using Beck Anxiety Inventory. Results After the intervention, the results revealed that anxiety score changes were statistically significant among the three groups (p < 0.001). In addition, it was found that the patients' mean anxiety scores significantly decreased in the aromatherapy and breathing exercise groups compared to with the pre-intervention scores (p < 0.001). Conclusion Aromatherapy with inhaled lavender essential oil and breathing exercises can be considered by clinical nurses as simple, applicable, and effective interventions to reduce ECT-related anxiety in depressed patients.

Ketamine Action on Astrocytes Provides New Insights into Rapid Antidepressant Mechanisms

Ketamine, a non-competitive N-methyl-D-aspartate receptor (NMDAR) antagonist, exerts rapid, potent and long-lasting antidepressant effect already after a single administration of a low dose into depressed individuals. Apart from targeting neuronal NMDARs essential for synaptic transmission, ketamine also interacts with astrocytes, the principal homoeostatic cells of the central nervous system. The cellular mechanisms underlying astrocyte-based rapid antidepressant effect are incompletely understood. Here we overview recent data that describe ketamine-dependent changes in astrocyte cytosolic cAMP activity ([cAMP]_i) and ketamine-induced modifications of stimulus-evoked Ca²⁺ signalling. The latter regulates exocytotic release of gliosignalling molecules and stabilizes the vesicle fusion pore in a narrow configuration that obstructs cargo discharge or vesicle membrane recycling. Ketamine also instigates rapid redistribution of cholesterol in the astrocyte plasmalemma that may alter flux of cholesterol to neurones, where it is required for changes in synaptic plasticity. Finally, ketamine attenuates mobility of vesicles carrying the inward rectifying potassium channel (K_ir4.1) and reduces the surface density of K_ir4.1 channels that control extracellular K⁺ concentration, which tunes the pattern of action potential firing in neurones of lateral habenula as demonstrated in a rat model of depression. Thus, diverse, but not mutually exclusive, mechanisms act synergistically to evoke changes in synaptic plasticity leading to sustained strengthening of excitatory synapses necessary for rapid antidepressant effect of ketamine.

Possible Hypothetical Mode of Action of ECT (Electroconvulsive Therapy) Based on DNA Dipole Character and Epigenetics

The human genome consists of roughly 23000 genes which cannot explain the enormous diversity of proteins or behavior. A second epigenetic code warrants adaptive variation of gene expression. The rationale of this variation are transfer reactions such as methylation, acetylation or phosphorylation of DNA or histones including reverse reactions which are supposed to be altered by electroconvulsive therapy (ECT). The method has been successfully used since the 1930ies but the underlying molecular mechanism of action has not been elucidated yet. The paper discusses the theoretical involvement of epigenetic gene expression as an adaptive process to explain biochemical changes after ECT administration.

Major depressive disorder: Validated treatments and future challenges

Depression is a prevalent psychiatric disorder that often leads to poor quality of life and impaired functioning. Treatment during the acute phase of a major depressive episode aims to help the patient reach a remission state and eventually return to their baseline level of functioning. Pharmacotherapy, especially selective serotonin reuptake inhibitors antidepressants, remains the most frequent option for treating depression during the acute phase, while other promising pharmacological options are still competing for the attention of practitioners. Depression-focused psychotherapy is the second most common option for helping patients overcome the acute phase, maintain remission, and prevent relapses. Electroconvulsive therapy is the most effective somatic therapy for depression in some specific situations; meanwhile, other methods have limits, and their specific indications are still being studied. Combining medications, psychotherapy, and somatic therapies remains the most effective way to manage resistant forms of depression.

Wound Healing with Electrical Stimulation Technologies: A Review

Electrical stimulation (ES) is an attractive field among clinicians in the topic of wound healing, which is common yet complicated and requires multidisciplinary approaches. The conventional dressing and skin graft showed no promise on complete wound closure. These urge the need for the exploration of electrical stimulation to supplement current wound care management. This review aims to provide an overview of electrical stimulation in wound healing. The mechanism of galvanotaxis related to wound repair will be reviewed at the cellular and molecular levels. Meanwhile, different modalities of externally applied electricity mimicking a physiologic electric field will be discussed and compared in vitro, in vivo, and clinically. With the emerging of tissue engineering and regenerative medicine, the integration of electroconductive biomaterials into modern miniaturised dressing is of interest and has become possible with the advancing understanding of smart biomaterials.

Efficacy of electroconvulsive therapy as a potential first-choice treatment in treatment-resistant depression (Review)

Electroconvulsive therapy (ECT) is a technique that has been used since 1938 to treat several psychiatric disorders as a replacement for chemically induced seizures. Despite its history of stigma, controversy and low accessibility, ECT is found to be beneficial and efficient in severe cases of depression where medication fails to bring results. Titration tables developed over time, based on evidenced-based medicine, have made this treatment technique safe and, in some cases, the first choice of treatment. The aim of the review was to summarize the research conducted on the efficacy of ECT on major depressive disorder and variables studied such as technique, comorbidities and medication as well as the effects and outcomes of this procedure. At the same time, the application and correlations with other psychiatric and neurological disorders, including catatonia, agitation and aggression in individuals with dementia, schizophrenia, and epilepsy were assessed. There are no statistically demonstrated effects due to the fact that a small number of moderate-quality studies have been published; however, the combination of ECT technique with standard medication and care, can improve patient outcome. Furthermore, with regard to ECT, widespread and robust volume changes in both cortical and subcortical regions have been shown. Antidepressant response and volumetric increases appear to be limited by the specific neuroplasticity threshold of each patient.

Therapeutic Horticulture as a Therapeutic Intervention in Patients Receiving Electroconvulsive Therapy (ECT) Treatment for Major Depressive Disorder

This study explored the effect of a structured therapeutic horticulture (TH) program on depression symptoms and quality of life indicators for individuals receiving inpatient electroconvulsive therapy (ECT) for major depressive disorders (MDD). Self-reported measures of depressive symptomatology (PHQ9, BDI-II) and quality of life (SF-36) were employed to compare intervention (n = 25) and control groups (n = 27), with the intervention group attending TH sessions for one-hour periods, twice per week, in addition to standard inpatient care associated with ECT received by both groups. All patients were assessed at admission, and after two weeks’ time or prior to discharge, during which the intervention group participated in a minimum of four TH sessions. Sessions were led by a horticultural therapist in an accessible on-campus greenhouse. Both groups improved significantly between assessment times one and two on both measures of depression, with a statistically significant difference in change scores for the BDI-II only, favoring the control over the intervention group (16.5, s.d. 12.78 versus 9.6, s.d. 10.15; p = 0.36). Both groups improved significantly on four of eight SF-36 subscales during the same period. A statistically significant difference in change scores was found for the Role Limitations-Physical Health (RLPH) subscale, where the intervention group improved between assessment periods, whereas the control group worsened (16.0, s.d.48.8 versus -9.3, s.d. 33.4; p = .033). Although quantifying group changes or improvement for individuals receiving intensive treatment for major depressive disorders (ECT) by the addition of an adjunct therapy is difficult, this study provides a basic premise for the consideration of various therapeutic horticulture settings to achieve therapeutic benefits through TH.

Clozapine: Why Is It So Uniquely Effective in the Treatment of a Range of Neuropsychiatric Disorders?

Clozapine is superior to other antipsychotics as a therapy for treatment-resistant schizophrenia and schizoaffective disorder with increased risk of suicidal behavior. This drug has also been used in the off-label treatment of bipolar disorder, major depressive disorder (MDD), and Parkinson's disease (PD). Although usually reserved for severe and treatment-refractory cases, it is interesting that electroconvulsive therapy (ECT) has also been used in the treatment of these psychiatric disorders, suggesting some common or related mechanisms. A literature review on the applications of clozapine and electroconvulsive therapy (ECT) to the disorders mentioned above was undertaken, and this narrative review was prepared. Although both treatments have multiple actions, evidence to date suggests that the ability to elicit epileptiform activity and alter EEG activity, to increase neuroplasticity and elevate brain levels of neurotrophic factors, to affect imbalances in the relationship between glutamate and γ-aminobutyric acid (GABA), and to reduce inflammation through effects on neuron-glia interactions are common underlying mechanisms of these two treatments. This evidence may explain why clozapine is effective in a range of neuropsychiatric disorders. Future increased investigations into epigenetic and connectomic changes produced by clozapine and ECT should provide valuable information about these two treatments and the disorders they are used to treat.

Ketamine Alters Functional Plasticity of Astroglia: An Implication for Antidepressant Effect

Ketamine, a non-competitive N–methyl–d–aspartate receptor (NMDAR) antagonist, exerts a rapid, potent and long-lasting antidepressant effect, although the cellular and molecular mechanisms of this action are yet to be clarified. In addition to targeting neuronal NMDARs fundamental for synaptic transmission, ketamine also affects the function of astrocytes, the key homeostatic cells of the central nervous system that contribute to pathophysiology of major depressive disorder. Here, I review studies revealing that (sub)anesthetic doses of ketamine elevate intracellular cAMP concentration ([cAMP]_i) in astrocytes, attenuate stimulus-evoked astrocyte calcium signaling, which regulates exocytotic secretion of gliosignaling molecules, and stabilize the vesicle fusion pore in a narrow configuration, possibly hindering cargo discharge or vesicle recycling. Next, I discuss how ketamine affects astrocyte capacity to control extracellular K⁺ by reducing vesicular delivery of the inward rectifying potassium channel (K_ir4.1) to the plasmalemma that reduces the surface density of Kir4.1. Modified astroglial K⁺ buffering impacts upon neuronal firing pattern as demonstrated in lateral habenula in a rat model of depression. Finally, I highlight the discovery that ketamine rapidly redistributes cholesterol in the astrocyte plasmalemma, which may alter the flux of cholesterol to neurons. This structural modification may further modulate a host of processes that synergistically contribute to ketamine’s rapid antidepressant action.

Electroconvulsive Therapy and Movement Disorders. New Perspectives on A Time-Tested Therapy

Electroconvulsive therapy (ECT) has been a very well known therapy in Psychiatry for over 80 years. ECT is considered useful in treating acute mania, severe depression and other psychiatric conditions. Over time, this therapy has also been used in several movement disorders including Parkinson disease (PD) and Huntington disease (HD). In this brief review, I summarize the recent History and evolution of ECT, its proven and potential applications in movement disorders as well as its potential mechanisms.

Auricular Vagus Neuromodulation-A Systematic Review on Quality of Evidence and Clinical Effects

Background: The auricular branch of the vagus nerve runs superficially, which makes it a favorable target for non-invasive stimulation techniques to modulate vagal activity. For this reason, there have been many early-stage clinical trials on a diverse range of conditions. These trials often report conflicting results for the same indication. Methods: Using the Cochrane Risk of Bias tool we conducted a systematic review of auricular vagus nerve stimulation (aVNS) randomized controlled trials (RCTs) to identify the factors that led to these conflicting results. The majority of aVNS studies were assessed as having "some" or "high" risk of bias, which makes it difficult to interpret their results in a broader context. Results: There is evidence of a modest decrease in heart rate during higher stimulation dosages, sometimes at above the level of sensory discomfort. Findings on heart rate variability conflict between studies and are hindered by trial design, including inappropriate washout periods, and multiple methods used to quantify heart rate variability. There is early-stage evidence to suggest aVNS may reduce circulating levels and endotoxin-induced levels of inflammatory markers. Studies on epilepsy reached primary endpoints similar to previous RCTs testing implantable vagus nerve stimulation therapy. Preliminary evidence shows that aVNS ameliorated pathological pain but not evoked pain. Discussion: Based on results of the Cochrane analysis we list common improvements for the reporting of results, which can be implemented immediately to improve the quality of evidence. In the long term, existing data from aVNS studies and salient lessons from drug development highlight the need for direct measures of local neural target engagement. Direct measures of neural activity around the electrode will provide data for the optimization of electrode design, placement, and stimulation waveform parameters to improve on-target engagement and minimize off-target activation. Furthermore, direct measures of target engagement, along with consistent evaluation of blinding success, must be used to improve the design of controls-a major source of concern identified in the Cochrane analysis. The need for direct measures of neural target engagement and consistent evaluation of blinding success is applicable to the development of other paresthesia-inducing neuromodulation therapies and their control designs.

Resting State Functional Connectivity of Brain With Electroconvulsive Therapy in Depression: Meta-Analysis to Understand Its Mechanisms

Introduction: Electroconvulsive therapy (ECT) is a commonly used brain stimulation treatment for treatment-resistant or severe depression. This study was planned to find the effects of ECT on brain connectivity by conducting a systematic review and coordinate-based meta-analysis of the studies performing resting state fMRI (rsfMRI) in patients with depression receiving ECT. Methods: We systematically searched the databases published up to July 31, 2020, for studies in patients having depression that compared resting-state functional connectivity (rsFC) before and after a course of pulse wave ECT. Meta-analysis was performed using the activation likelihood estimation method after extracting details about coordinates, voxel size, and method for correction of multiple comparisons corresponding to the significant clusters and the respective rsFC analysis measure with its method of extraction. Results: Among 41 articles selected for full-text review, 31 articles were included in the systematic review. Among them, 13 articles were included in the meta-analysis, and a total of 73 foci of 21 experiments were examined using activation likelihood estimation in 10 sets. Using the cluster-level interference method, one voxel-wise analysis with the measure of amplitude of low frequency fluctuations and one seed-voxel analysis with the right hippocampus showed a significant reduction (p < 0.0001) in the left cingulate gyrus (dorsal anterior cingulate cortex) and a significant increase (p < 0.0001) in the right hippocampus with the right parahippocampal gyrus, respectively. Another analysis with the studies implementing network-wise (posterior default mode network: dorsomedial prefrontal cortex) resting state functional connectivity showed a significant increase (p < 0.001) in bilateral posterior cingulate cortex. There was considerable variability as well as a few key deficits in the preprocessing and analysis of the neuroimages and the reporting of results in the included studies. Due to lesser studies, we could not do further analysis to address the neuroimaging variability and subject-related differences. Conclusion: The brain regions noted in this meta-analysis are reasonably specific and distinguished, and they had significant changes in resting state functional connectivity after a course of ECT for depression. More studies with better neuroimaging standards should be conducted in the future to confirm these results in different subgroups of depression and with varied aspects of ECT.

[Anesthesia for electroconvulsive therapy]

Electroconvulsive therapy (ECT) is an important component in the treatment of depression and schizophrenia in Germany. For this intervention patients undergo short-term general anesthesia and muscle relaxation. Before anesthesia can be carried out patients are subject to a comprehensive examination. For general anesthesia all established hypnotics can be used, but differences with respect to the success of the ECT have been described. Short-acting or reversible relaxants should be preferentially used. The risks of general anesthesia during ECT are estimated to be low but a transient hemodynamic instability of patients can occur. Treatment can be performed as an inpatient but also as an outpatient procedure.

Astrocytes in rapid ketamine antidepressant action

Ketamine, a general anaesthetic and psychotomimetic drug, exerts rapid, potent and long-lasting antidepressant effect, albeit the cellular and molecular mechanisms of this action are yet to be discovered. Besides targeting neuronal NMDARs fundamental for synaptic transmission, ketamine affects the function of astroglia the key homeostatic cells of the central nervous system that contribute to pathophysiology of psychiatric diseases including depression. Here we review studies revealing that (sub)anaesthetic doses of ketamine elevate intracellular cAMP concentration ([cAMP]_i) in astrocytes, attenuate stimulus-evoked astrocyte calcium signalling, which regulates exocytotic secretion of gliosignalling molecules, and stabilize the vesicle fusion pore in a narrow configuration possibly hindering cargo discharge or vesicle recycling. Next we discuss how ketamine affects astroglial capacity to control extracellular K⁺ by reducing cytoplasmic mobility of vesicles delivering the inward rectifying potassium channel (Kir4.1) to the plasmalemma. Modified astroglial K⁺ buffering impacts upon neuronal excitability as demonstrated in the lateral habenula rat model of depression. Finally, we highlight the recent discovery that ketamine rapidly redistributes cholesterol in the plasmalemma of astrocytes, but not in fibroblasts nor in neuronal cells. This alteration of membrane structure may modulate a host of processes that synergistically contribute to ketamine's rapid and prominent antidepressant action.