Searching for the mechanism(s) of ECT's therapeutic effect

Psychodynamically Informed Brain Stimulation: Building a Bridge from Brain to Mind

Since its inception, psychiatry has undergone several periods of radical identity transformation. Initially limited to psychotherapy alone, the advent of medications stimulated an era of biological psychiatry. For years, medications served as the mainstay of biological treatments, paralleled by a rise in treatment resistance. Brain stimulation therapies are psychiatry's newest arm of intervention and represent an area ripe for exploration. These techniques offer new hope to treatment-resistant patients, but in a manner often dissociated from psychoanalytic conceptualization and the practice of psychotherapy. There is growing interest in bridging this divide. In this article, we continue the efforts at interweaving what may seem to be disparate approaches through the topic of treatment resistance. This article aims to engage interventional psychiatrists in considering psychosocial dimensions of their treatments and to provide education for psychoanalytic clinicians on the history, mechanism of action, and applications of brain stimulation technologies.

The Role of the Autonomic Nervous System in the Mediation of the Resolution of Suicidal Ideation With Electroconvulsive Therapy: A Hypothesis and Review of Heart Rate Variability Over a Course of Electroconvulsive Therapy

ABSTRACT

Longitudinal observational studies have shown a meaningful decrease in suicidal thinking and suicidal behavior after receipt of electroconvulsive therapy (ECT). The antisuicide effect of ECT may be related to success in the global relief of the presenting syndrome such as depressive or psychotic illness. However, it is possible that the antisuicide effect is specific to ECT per se, over and above the relief of the clinical syndrome. Electroconvulsive therapy is associated with many observable neurochemical and physiologic effects, and some of these may plausibly be specifically linked to an antisuicide effect. The phenomenon of physiologic hyperarousal has been named as a candidate mechanism driving the risk for suicide. Hyperarousal is associated with decreased neuropsychological executive function responsible for response inhibition and can lead to impulsive action. The level of arousal within the autonomic nervous system (ANS) can be assayed with the pupillary light reflex, electrodermal activity, or with heart rate variability (HRV). This article summarizes the literature on the effects of ECT on HRV 24 to 72 hours after a course of ECT and finds evidence for increases in HRV, which indicates lower levels of arousal in the ANS. This finding suggests that ECT-related reductions in ANS arousal, presumably with corresponding improvements in response inhibition, may be one mechanism whereby ECT reduces risk for suicide.

What Can We Tell About the Effect of Electroconvulsive Therapy on the Human Hippocampus?

Electroconvulsive therapy (ECT) is the most effective antidepressant treatment, although its mechanisms of action remain unclear. Since 2010, several structural magnetic resonance imaging studies based on a neuroplastic hypothesis have consistently reported increases in the hippocampal volume following ECT. Moreover, volume increases in the human dentate gyrus, where neurogenesis occurs, have also been reported. These results are in line with the preclinical findings of ECT-induced neuroplastic changes, including neurogenesis, gliogenesis, synaptogenesis, and angiogenesis, in rodents and nonhuman primates. Despite this robust evidence of an effect of ECT on hippocampal plasticity, the clinical relevance of these human hippocampal changes continues to be questioned. This narrative review summarizes recent findings regarding ECT-induced hippocampal volume changes. Furthermore, this review also discusses methodological considerations and future directions in this field.

Effect of early electroconvulsive therapy on length of stay in patients with bipolar, depressive and psychotic disorders

OBJECTIVE

There is limited literature examining the effect of early electroconvulsive therapy(ECT) on the length of stay(LOS), especially for psychotic disorders. This study aimed to evaluate the association between early ECT and LOS in three main groups of patients with bipolar, depressive and primary psychotic disorders.

METHOD

A retrospective descriptive analysis of 464 patients who received inpatient ECT from May 2017 to March 2021 in a large tertiary psychiatric institution was conducted. Early ECT was defined as ECT done before the mean number of days from admission to initiation of ECT by diagnosis. The main outcome measure was LOS, which was examined by diagnosis between the early and late ECT groups, using a linear regression model with adjustment factors chosen based on univariate analysis.

RESULTS

A strong, significant association was found between early ECT and a shorter LOS (β -28.3, 95 % CI -33.6 to -23.0, p < 0.001), even after accounting for adjustment factors. This association was consistent in all three diagnosis groups: bipolar disorders (β -14.5, 95 % CI -20.1 to -9.0, p < 0.001), major depressive disorder (β -18.2, 95 % CI -27.1 to -9.3, p < 0.001) and psychotic disorders (β -39.0, 95 % CI -46.8 to -31.2, p < 0.001). There was no significant difference in the 30-day readmission rates between the early and late ECT groups trans-diagnostically.

CONCLUSION

Early ECT is strongly associated with a shorter LOS across a range of diagnostic indications including major depressive disorder, bipolar disorder and schizophrenia. ECT can be considered earlier in treatment-decision algorithms and may offer a reduction in LOS.

Alterations in the Serum Proteome Following Electroconvulsive Therapy for a Major Depressive Episode: A Longitudinal Multicenter Study

Background

Electroconvulsive therapy (ECT) is the most effective treatment for severe depression, but the biological changes induced by ECT remain poorly understood.

Methods

This study investigated alterations in blood serum proteins in 309 patients receiving ECT for a major depressive episode. We analyzed 201 proteins in samples collected at 3 time points (T): just before the first ECT treatment session (T0), within 30 minutes after the first ECT session (T1), and just before the sixth ECT session (T2).

Results

Using statistical models to account for repeated sampling, we identified 152 and 70 significantly (<5% false discovery rate) altered proteins at T1 and T2, respectively. The most pronounced alterations at T1 were transiently increased levels of prolactin, myoglobin, and kallikrein-6. However, most proteins had decreased levels at T1, with the largest effects observed for pro-epidermal growth factor, proto-oncogene tyrosine-protein kinase Src, tumor necrosis factor ligand superfamily member 14, sulfotransferase 1A1, early activation antigen CD69, and CD40 ligand. The change of several acutely altered proteins correlated with electric current and pulse frequency in a dose-response-like manner. Over a 5-session course of ECT, some acutely altered levels were sustained while others increased, e.g., serine protease 8 and chitinase-3-like protein 1. None of the studied protein biomarkers were associated with clinical response to ECT.

Conclusions

We report experimental data on alterations in the circulating proteome triggered by ECT in a clinical setting. The findings implicate hormonal signaling, immune response, apoptotic processes, and more. None of the findings were associated with clinical response to ECT.

The Rise, Fall, and Resurgence of Electroconvulsive Therapy

Electroconvulsive therapy (ECT) is one of the most effective treatments for depression. However, significant stigma from the media and the antipsychiatry movement has biased the public toward ECT, leading to underutilization, particularly among those most in need. This report reviews some of the key historical events in the rise, fall, and resurgence of ECT and how modern ECT knowledge and practice are more refined, including an improved understanding of its mechanisms of action and optimal treatment parameters.

One century of healing currents into the brain from the scalp: From electroconvulsive therapy to repetitive transcranial magnetic stimulation for neuropsychiatric disorders

Electroconvulsive therapy (ECT) was applied for the first time in humans in 1938: after 80 years, it remains conceptually similar today except for modifications of the original protocol aimed to reduce adverse effects (as persistent memory deficits) without losing clinical efficacy. We illustrate the stages of development as well as ups and downs of ECT use in the last eighty years, and the impact that it still maintains for treatment of certain psychiatric conditions. Targeted, individualized and safe noninvasive neuromodulatory interventions are now possible for many neuropsychiatric disorders thanks to repetitive transcranial magnetic stimulation (rTMS) that injects currents in the brain through electromagnetic induction, powerful enough to depolarize cortical neurons and related networks. Although ECT and rTMS differ in basic concepts, mechanisms, tolerability, side effects and acceptability, and beyond their conceptual remoteness (ECT) or proximity (rTMS) to "precision medicine" approaches, the two brain stimulation techniques may be considered as complementary rather than competing in the current treatment of certain neuropsychiatric disorders.

Electroconvulsive Therapy for Patients with Catatonia: Current Perspectives

Catatonia is a serious, common syndrome of motoric and behavioral dysfunction, which carries high morbidity and mortality. Electroconvulsive therapy (ECT) is the definitive treatment for catatonia, but access to ECT for the treatment of catatonia remains inappropriately limited. Catatonia is observable, detectable, and relevant to various medical specialties, but underdiagnosis impedes the delivery of appropriate treatment and heightens risk of serious complications including iatrogenesis. Current understanding of catatonia's pathophysiology links it to the current understanding of ECT's mechanism of action. Definitive catatonia care requires recognition of the syndrome, workup to identify and treat the underlying cause, and effective management including appropriate referral for ECT. Even when all of these conditions are met, and despite well-established data on the safety and efficacy of ECT, stigma surrounding ECT and legal restrictions for its use in catatonia are additional critical barriers. Addressing the underdiagnosis of catatonia and barriers to its treatment with ECT is vital to improving outcomes for patients. While no standardized protocols for treatment of catatonia with ECT exist, a large body of research guides evidence-based care and reveals where additional research is warranted. The authors conducted a review of the literature on ECT as a treatment for catatonia. Based on the review, the authors offer strategies and future directions for improving access to ECT for patients with catatonia, and propose an algorithm for the treatment of catatonia with ECT.

Cortical and striatal serotonin transporter binding in a genetic rat model of depression and in response to electroconvulsive stimuli

Depression is a debilitating mental illness and two thirds of patients respond insufficiently to conventional antidepressants. Electroconvulsive therapy (ECT) remains the most effective treatment to alleviate drug-refractory depression, however the neurobiological mechanisms are mostly unknown. The serotonergic system plays an important role in depression and alterations in the serotonin transporter (SERT) are seen both in depression and response to antidepressant pharmacotherapies. The first aim of this study was to investigate SERT density in a genetic rat model of depression, Flinders Sensitive Line (FSL), compared to control Flinders Resistant Line (FRL) and Sprague-Dawley (SD) rats. The second aim was to investigate SERT density in response to electroconvulsive stimuli (ECS), an animal model of ECT. Female rats of each strain were treated with ECS or sham (ear-clip placement with no current) for 10 days before brains were removed, frozen and cut into 20 µm thick sections. SERT density was measured in striatal and cortical regions by quantitative in vitro autoradiography using the SERT-radioligand, [³H]-DASB. Higher SERT density was observed in FSL rats compared to SD rats by 36-48% in motor cortex and striatum under sham conditions. In response to ECS, SD rats displayed a significant effect of treatment, whereas no changes were observed in FRL and FSL rats. Increased SERT binding in FSL rats compared to SD supports a dysfunction of the serotonergic system in depression. The increased SERT density after ECS, seen in SD rats but not FSL rats, suggests a different mechanism of action between depressive-like rats and controls.

Bringing Neuroscience to the Bedside

Clinical psychiatry has not historically expected practitioners to learn the basic science of psychiatric illness. Despite wide recognition that all effective psychiatric treatments have neurophysiological mechanisms, the field has struggled to integrate concepts of the mind and brain. Because of historical separations of clinical psychiatry and evolving neuroscience research, many psychiatric residency programs feel underresourced to teach clinically relevant neuroscience, and current residency graduates are not being prepared to integrate neuroscience findings into their practice. Significant strides have been made in the understanding of the neurobiology of psychiatric disorders. Similarly, the neurobiological mechanisms of a wide variety of treatments have been elucidated, spanning interventions from psychotherapy to physical exercise, electroconvulsive therapy, and modern neuromodulation techniques. The authors discuss strategies for integrating the language of clinical neuroscience into everyday psychiatric practice and review resources available to clinicians and trainees to help them acquire and practice these skills.

Changes in cardiac autonomic nervous system activity during a course of electroconvulsive therapy

AIM

Although electroencephalogram (EEG) seizure duration and seizure threshold change during a course of electroconvulsive therapy, the mechanisms by which these factors influence heart rate during subsequent electroconvulsive therapy sessions are currently unclear. In the current study, we investigated changes in heart rate during electroconvulsive therapy.

METHODS

We recorded electroencephalography and electrocardiography during electroconvulsive therapy in 12 patients with major depressive disorder. Baseline heart rate was defined as the mean heart rate in the 30 seconds prior to stimulus onset. The Time_Max peak refers to the maximum heart rate after stimulus onset. Time_1/2 points represent the time points at which the heart rate had decreased to a value midway between the baseline heart rate and the Time_Max peak. We examined the relationships between EEG seizure duration, Time_Max , and Time_1/2 throughout the course of electroconvulsive therapy.

RESULTS

Time_1/2 decreased as the number of electroconvulsive sessions increased. Time_1/2 was positively correlated with EEG seizure duration.

CONCLUSION

The duration in which electroconvulsive therapy-induced sympathetic nervous system activation returned halfway to baseline levels gradually shortened during the course of electroconvulsive therapy.

The relationship between seizure in electroconvulsive therapy and pupillary response using an automated pupilometer

OBJECTIVES

Seizure duration and morphology, postictal suppression, and sympathetic nervous system activation are all recommended as assessments of adequate seizure in electroconvulsive therapy (ECT). However, blood pressure and heart rate are not typically assessed as part of sympathetic nervous system activation because of the administration of anesthetic or cardiovascular agents during ECT. Although the pupils are known to reflect to the activity of autonomic nervous system and the degree of brain damage, previous studies have not examined the relationship between seizure of electroconvulsive therapy and pupillary response.

METHODS

We conducted 98 sessions of ECT with 13 patients, divided into two groups according to seizure quality: (1) adequate or (2) inadequate. Pupillary light reflex [% constriction = (maximum resting pupil size {MAX} - minimum pupil size after light stimulation)/MAX × 100] was measured using a portable infrared quantitative pupilometer before anesthesia induction and immediately after electrical stimulation.

RESULTS

The number regarded as adequate was 67 times and as inadequate was 31 times. Maximum pupil size at the control and immediately after electrical stimulation was similar between the adequate and inadequate groups. Pupillary light reflex was similar at the control between both groups, but significantly smaller immediately after stimulation in the adequate group (2.5 ± 3.6%) compared with the inadequate group (10.6 ± 11.5%). Receiver operating characteristic curve analysis revealed that pupillary light reflex (> 5.5%) predicted adequate seizure.

CONCLUSIONS

The current findings suggest that pupillary constriction immediately after ECT could provide a helpful method for assessing the efficacy of ECT.

Increased resting-state global functional connectivity density of default mode network in schizophrenia subjects treated with electroconvulsive therapy

Modified electroconvulsive therapy (MECT) has been widely applied to help treat schizophrenia patients who are treatment-resistant to pharmaceutical therapy. Although the technique is increasingly prevalent, the underlying neural mechanisms have not been well clarified. We conducted a longitudinal study to investigate the alteration of global functional connectivity density (gFCD) in schizophrenia patients undergoing MECT using resting state fMRI (functional magnetic resonance imaging). Two groups of schizophrenia inpatients were recruited. One group received a four-week MECT together with antipsychotic drugs (ECT+Drug, n=21); the other group only received antipsychotic drugs (Drug, n=21). Both groups were compared to a sample of healthy controls (HC, n=23). fMRI scans were obtained from the schizophrenia patients twice at baseline (t₁) and after 4-week treatment (t₂), and from healthy controls at baseline. gFCD was computed using resting state fMRI. Repeated ANCOVA showed a significant interaction effect of group×time in the schizophrenia patients in left precuneus (Pcu), ventral medial prefrontal cortex (vMPFC), and dorsal medial prefrontal cortex (dMPFC) (GRF-corrected P<0.05), which are mainly located within the default mode network (DMN). Post-hoc analysis revealed that compared with baseline (t₁), an increased gFCD was found in the ECT+Drug group in the dMPFC (t=3.87, p=0.00095), vMPFC (t=3.95, p=0.00079) and left Pcu (t=3.33, p=0.0034), but no significant effect was identified in the Drug group. The results suggested that increased global functional connectivity density within the DMN might be one important neural mechanism of MECT in schizophrenia.

General Anesthetics to Treat Major Depressive Disorder: Clinical Relevance and Underlying Mechanisms

Major depressive disorder is a frequent and devastating psychological condition with tremendous public health impact. The underlying pathophysiological mechanisms involve abnormal neurotransmission and a relatedly impaired synaptic plasticity. Since general anesthetics are potent modulators of neuronal activity and, thereby, can exert long-term context-dependent impact on neural networks, an intriguing hypothesis is that these drugs could enhance impaired neural plasticity associated with certain psychiatric diseases. Clinical observations over the past few decades appear to confirm this possibility. Indeed, equipotency of general anesthesia alone in comparison with electroconvulsive therapy under general anesthesia has been demonstrated in several clinical trials. Importantly, in the past 15 years, intravenous administration of subanesthetic doses of ketamine have also been demonstrated to have rapid antidepressant effects. The molecular, cellular, and network mechanisms underlying these therapeutic effects have been partially identified. Although several important questions remain to be addressed, the ensemble of these experimental and clinical observations opens new therapeutic possibilities in the treatment of depressive disorders. Importantly, they also suggest a new therapeutic role for anesthetics that goes beyond their principal use in the perioperative period to facilitate surgery.

Potential Mechanisms Underlying the Therapeutic Effects of Electroconvulsive Therapy

In spite of the extensive application of electroconvulsive therapy (ECT), how it works remains unclear. So far, researchers have made great efforts in figuring out the mechanisms underlying the effect of ECT treatment via determining the levels of neurotransmitters and cytokines and using genetic and epigenetic tools, as well as structural and functional neuroimaging. To help address this question and provide implications for future research, relevant clinical trials and animal experiments are reviewed.

Sleep at baseline and after electroconvulsive therapy in patients with major depression

Sleep in major depressive disorder is frequently altered and possibly indicative for treatment outcomes. For example, increased rapid eye movement (REM-) sleep density seems to predict worse treatment outcomes of psychotherapy. We therefore investigated pre-treatment sleep and sleep changes after termination of electroconvulsive therapy (ECT). Sleep was polysomnographically recorded. The analysed sample consisted of 15 inpatients with ages ranging from 30 to 80 (mean 59 years). ECT was applied two times a week up to 7 weeks. Stable remission of depressive symptoms was defined by a score in the Hamilton Rating Scale of Depression <8 at six months after ECT. The main results were an increase in sleep efficiency and a decrease in the number of awakenings within the course of ECT in the entire patient group. Significant increases in slow wave sleep and REM sleep duration and a significant decrease in REM density were only seen in stable remitters and not in non-remitters. In pre-treatment baseline sleep a higher REM density of the first REM sleep period was significantly associated with better ECT outcome. In conclusion, REM density of the first REM sleep period seems to be an interesting candidate as putative predictor of stable treatment outcome of ECT.

Seizure Adequacy Markers and the Prediction of Electroconvulsive Therapy Response

OBJECTIVES

Electroconvulsive therapy (ECT) is the most effective therapy for patients with treatment-resistant depression; however, some patients do not respond or relapse in a short time. Electroconvulsive therapy stimulus parameters may be related to the outcome. We carried out a retrospective study review to investigate various ECT parameters in relation to the outcome, clinical variables, and pharmacological treatments. Our aim was to understand which factors could be considered putative seizure quality markers and which are relevant to clinical practice.

METHODS

Two physicians evaluated the seizure length, the postictal suppression index, the wave amplitude, tachycardia, and hemispheric brain wave synchronicity in a double-blind manner for 45 treatment-resistant depression patients receiving ECT.

RESULTS

The analysis showed a significant association between the outcome and the ECT seizure quality measured by the parameters (P = 9.9 × 10). Among patients with poor-quality seizures, 61.5% relapsed after approximately 1 month from the last ECT session. Particularly, there was an association between higher symptomatology decrease and higher quality of hemispheric brain wave synchronicity (P = 5.0 × 10), as well as a higher wave amplitude (P = 0.01).

CONCLUSIONS

Our results confirm that ECT seizure quality was strongly correlated with the decrease of depressive symptomatology.

Influence of GRIK4 genetic variants on the electroconvulsive therapy response

Several lines of evidence have shown the involvement of the glutamatergic system in the function of electroconvulsive therapy (ECT). In particular, patients with treatment resistant depression (TRD) and chronic depression have lower levels of glutamate/glutamine than controls, and ECT can reverse this deficit. Genetic factors might contribute to modulating the mechanisms underlying ECT. This study aimed to evaluate the relationship between three polymorphisms (rs1954787, rs4936554 and rs11218030) of the glutamate receptor ionotropic kainate 4 (GRIK4) gene and responsiveness to ECT treatment in a sample of one hundred individuals, TRD or depressive Bipolar Disorder patients resistant to pharmacological treatments. The results revealed that GRIK4 variants were significantly associated with the response to ECT. In particular, we found that patients carrying the G allele of the GRIK4 rs11218030 had a significantly poorer response to ECT (p=2.71×10(-4)), showing five times the risk of relapse after ECT compared to the AA homozygotes. Analogously, patients carrying the GG rs1954787 genotype and rs4936554A allele carriers presented a double risk of lack of response after ECT (p=0.013 and p=0.040, respectively). In conclusion, the current study provides new evidence, indicating that some GRIK4 variants modulate the response to ECT in patients with depression resistant to treatment, suggesting a role for kainate receptor modulation.

Levels of serum immunomodulators and alterations with electroconvulsive therapy in treatment-resistant major depression

Studies in recent years have indicated that neuroimmunological events and immune activation may have a place in the etiology of depression. It has been suggested from data that there is a causal relationship between activation of the immune system and excessive release of proinflammatory cytokines, such as interleukin 1 (IL-1), IL-6, and tumor necrosis factor-alpha (TNF-alpha), and the etiology of depression. Although the mechanism of action of electroconvulsive therapy (ECT) is unclear, there is evidence that it can reduce cytokines and immune system changes. In our study, we aimed to determine how levels of serum immunomodulators were affected by ECT in major depression patients. This study was conducted on 50 patients with treatment-resistant major depression. The data of the patients were compared with 30 healthy individuals with similar demographic characteristics. A clinical response occurred in the patients and at the end of therapy, IL-1, IL-6, TNF-alpha, IL-10, IL-4, and interferon-gamma levels were measured. The disease severity was assessed with the 17-item Hamilton Depression Rating Scale. Data analysis was performed using SPSS Version 15. Significant differences were determined between the patients with major depression and control group with respect to basal serum IL-1, IL-6, TNF-alpha, IL-10, IL-4, and interferon-gamma levels. ECT treatment was shown to reduce these differences. ECT may cause significant changes in the activity of the immune system. The consideration of the relationship between the immune endocrine neurotransmitter systems could contribute to new theories regarding the mechanism of antidepressant treatment and biology of depression.

Memantine in the prevention or alleviation of electroconvulsive therapy induces cognitive disorders: A placebo controlled trial

The purpose of this study was to evaluate the effect of memantine administration on the adverse cognitive effects of electroconvulsive therapy (ECT). Forty patients diagnosed with a major depressive disorder for which ECT was indicated as a treatment for their current episode were randomly allocated to either the memantine (5mg/day) group or the placebo group. All patients underwent the same protocol for anaesthesia and ECT procedures. The patients received memantine or the placebo for the whole period of ECT treatment, starting the day before ECT and continuing until the fourth session of ECT. The Modified Mental State Examination (MMSE) was used for the assessment of cognition before and after the trial. Regarding MMSE and item 3 MMSE (related to recent memory), the memantine group scored significantly higher at the end of ECT sessions than the control group (P=0.02, P<0.001, respectively). Our data support the hypothesis that memantine may reduce cognitive impairment following ECT. Memantine could be both a safe and well-tolerated treatment for use with ECT.