Molecular mechanisms underlying structural plasticity of electroconvulsive therapy in major depressive disorder

Although previous studies reported structural changes associated with electroconvulsive therapy (ECT) in major depressive disorder (MDD), the underlying molecular basis of ECT remains largely unknown. Here, we combined two independent structural MRI datasets of MDD patients receiving ECT and transcriptomic gene expression data from Allen Human Brain Atlas to reveal the molecular basis of ECT for MDD. We performed partial least square regression to explore whether/how gray matter volume (GMV) alterations were associated with gene expression level. Functional enrichment analysis was conducted using Metascape to explore ontological pathways of the associated genes. Finally, these genes were further assigned to seven cell types to determine which cell types contribute most to the structural changes in MDD patients after ECT. We found significantly increased GMV in bilateral hippocampus in MDD patients after ECT. Transcriptome-neuroimaging association analyses showed that expression levels of 726 genes were positively correlated with the increased GMV in MDD after ECT. These genes were mainly involved in synaptic signaling, calcium ion binding and cell-cell signaling, and mostly belonged to excitatory and inhibitory neurons. Moreover, we found that the MDD risk genes of CNR1, HTR1A, MAOA, PDE1A, and SST as well as ECT related genes of BDNF, DRD2, APOE, P2RX7, and TBC1D14 showed significantly positive associations with increased GMV. Overall, our findings provide biological and molecular mechanisms underlying structural plasticity induced by ECT in MDD and the identified genes may facilitate future therapy for MDD.

Characterization of gray matter volume changes from one week to 6 months after termination of electroconvulsive therapy in depressed patients

BACKGROUND

Increased gray matter volume (GMV) following electroconvulsive therapy (ECT) has been well-documented, with limited studies reporting a subsequent decrease in GMV afterwards.

OBJECTIVE

This study characterized the reversion pattern of GMV after ECT and its association with clinical depression outcome, using multi-site triple time-point data from the Global ECT-MRI Research Collaboration (GEMRIC).

METHODS

86 subjects from the GEMRIC database were included, and GMV in 84 regions-of-interest (ROI) was obtained from automatic segmentation of T1 MRI images at three timepoints: pre-ECT (T0), within one-week post-ECT (T1), and one to six months post-ECT (T2). RM-ANOVAs were used to assess longitudinal changes and LMM analyses explored associations between GMV changes and demographical and clinical characteristics.

RESULTS

63 of the 84 ROIs showed a significant increase-and-decrease pattern (RM-ANOVA, Bonferroni corrected p < 0.00059). Post hoc tests indicated a consistent pattern in each of these 63 ROIs: significant increase from T0 to T1inGMV, followed by significant decrease from T1 to T2 and no difference between T0 and T2, except for both amygdalae, right hippocampus and pars triangularis, which showed the same increase and decrease but GMV at T2 remained higher compared to T0. No consistent relationship was found between GMV change pattern and clinical status.

CONCLUSION

The GEMRIC cohort confirmed a rapid increase of GMV after ECT followed by reversion of GMV one to six months thereafter. The lack of association between the GMV change pattern and depression outcome scores implies a transient neurobiological effect of ECT unrelated to clinical improvement.

Neurogenesis-independent mechanisms of MRI-detectable hippocampal volume increase following electroconvulsive stimulation

Electroconvulsive therapy (ECT) is one of the most effective psychiatric treatments but the underlying mechanisms are still unclear. In vivo human magnetic resonance imaging (MRI) studies have consistently reported ECT-induced transient hippocampal volume increases, and an animal model of ECT (electroconvulsive stimulation: ECS) was shown to increase neurogenesis. However, a causal relationship between neurogenesis and MRI-detectable hippocampal volume increases following ECT has not been verified. In this study, mice were randomly allocated into four groups, each undergoing a different number of ECS sessions (e.g., 0, 3, 6, 9). T2-weighted images were acquired using 11.7-tesla MRI. A whole brain voxel-based morphometry analysis was conducted to identify any ECS-induced brain volume changes. Additionally, a histological examination with super-resolution microscopy was conducted to investigate microstructural changes in the brain regions that showed volume changes following ECS. Furthermore, parallel experiments were performed on X-ray-irradiated mice to investigate the causal relationship between neurogenesis and ECS-related volume changes. As a result, we revealed for the first time that ECS induced MRI-detectable, dose-dependent hippocampal volume increase in mice. Furthermore, increased hippocampal volumes following ECS were seen even in mice lacking neurogenesis, suggesting that neurogenesis is not required for the increase. The comprehensive histological analyses identified an increase in excitatory synaptic density in the ventral CA1 as the major contributor to the observed hippocampal volume increase following ECS. Our findings demonstrate that modification of synaptic structures rather than neurogenesis may be the underlying biological mechanism of ECT/ECS-induced hippocampal volume increase.

Risk Phenotypes, Comorbidities, Pharmacotherapy, and Electroconvulsive Therapy (ECT) in a Cohort with Difficult-to-Treat Depression in Comparison to an Unmedicated Control Group

BACKGROUND

Approximately 15-25% of depressed patients suffer from difficult-to-treat depression (DTD). Patients with DTD require a thorough examination to avoid the oversight of treatable (psychiatric/somatic) comorbidities or (pseudo-)resistance to antidepressant drugs (ADs). Polymorphisms of the cytochrome P450 (CYP) enzymes 2D6 and 2C19, which play a major role in the metabolism of ADs, may contribute to resistance to ADs. Patients with DTD might benefit from electroconvulsive therapy (ECT).

METHODS

We enrolled 109 patients with DTD and 29 untreated depressed controls (UDC). We assessed risk phenotypes, comorbidities, and treatment, including ECT. We also performed pharmacokinetic analyses of CYP2D6 and CYP2C19.

RESULTS

DTD patients significantly more often suffered from comorbid psychiatric diseases, especially ICD-10: F40-F48 (DTD:40.4%, UDC:17.2%, OR 11.87, p=0.011) than UDC patients. DTD patients receiving ECT were more likely to achieve remission (37.7% vs. 11.8%, OR=3.96, p=0.023). Treatment with ADs did not differ between remitters and non-remitters. No significant differences were observed in the distribution of CYP2D6 and CYP2C19 variants between both groups.

CONCLUSION

Patients with DTD appear to experience comorbid neurotic stress and somatoform disorders (ICD-10: F40 - F48) more frequently. Therefore, a comprehensive differential diagnosis is crucial when patients do not respond sufficiently to antidepressant medication. Genotyping CYP2D6 and CYP2C19 should be considered.

Genome-Wide Association Study of Treatment-Resistant Depression: Shared Biology With Metabolic Traits

OBJECTIVE

Treatment-resistant depression (TRD) occurs in roughly one-third of all individuals with major depressive disorder (MDD). Although research has suggested a significant common variant genetic component of liability to TRD, with heritability estimated at 8% when compared with non-treatment-resistant MDD, no replicated genetic loci have been identified, and the genetic architecture of TRD remains unclear. A key barrier to this work has been the paucity of adequately powered cohorts for investigation, largely because of the challenge in prospectively investigating this phenotype. The objective of this study was to perform a well-powered genetic study of TRD.

METHODS

Using receipt of electroconvulsive therapy (ECT) as a surrogate for TRD, the authors applied standard machine learning methods to electronic health record data to derive predicted probabilities of receiving ECT. These probabilities were then applied as a quantitative trait in a genome-wide association study of 154,433 genotyped patients across four large biobanks.

RESULTS

Heritability estimates ranged from 2% to 4.2%, and significant genetic overlap was observed with cognition, attention deficit hyperactivity disorder, schizophrenia, alcohol and smoking traits, and body mass index. Two genome-wide significant loci were identified, both previously implicated in metabolic traits, suggesting shared biology and potential pharmacological implications.

CONCLUSIONS

This work provides support for the utility of estimation of disease probability for genomic investigation and provides insights into the genetic architecture and biology of TRD.

Challenges in the Treatment of Psychotic Bipolar Depression

BACKGROUND

Psychotic bipolar depression (PBD) is a prevalent yet understudied psychiatric illness, and there are no specific guidelines or Food and Drug Administration-approved medications for its treatment. Recent studies suggest that some antipsychotics and mood stabilizers may be effective in managing bipolar depression; however, their effectiveness for PBD remains unclear. Given the urgent need for more focused research for managing PBD, we conducted a literature review to summarize the existing literature on PBD.

METHODS

We conducted an electronic literature search from the 1960s to 2023, utilizing PubMed, MEDLINE, EMBASE, and Google, and selected studies based on their relevance to PBD.

FINDINGS

PBD is a complex disorder, with 50%-75% of patients with bipolar disorder exhibiting psychotic features. This likelihood increases among those with a history of psychotic mania. Treatment guidelines often recommend a combination of mood stabilizers, antipsychotics, or electroconvulsive therapy, but they do not specify a first-line treatment. PBD symptoms can be masked by mixed high mood and energy feelings, potentially delaying diagnosis and treatment while increasing suicide risk. Limited research has evaluated outcomes of various treatments for PBD, and despite the lack of evidence for superior efficacy, in clinical practice, antipsychotics are frequently prescribed. Notably, combining an antipsychotic with selective noradrenaline reuptake inhibitors or tricyclic antidepressants may be effective, but including a mood stabilizer is necessary.

CONCLUSION

PBD poses a significant challenge in mental health due to its severity and the lack of consensus on optimal treatment approaches. There is a critical need for more dedicated clinical trials and research to answer key questions about the effective treatment of acute PBD, ideal follow-up care, traits of responders to different therapies, and decision models for subsequent treatments.

Electroconvulsive therapy disrupts functional connectivity between hippocampus and posterior default mode network

BACKGROUND

The mechanisms underlying memory deficits after electroconvulsive therapy (ECT) remain unclear but altered functional interactions between hippocampus and neocortex may play a role.

OBJECTIVES

To test whether ECT reduces functional connectivity between hippocampus and posterior regions of the default mode network (DMN) and to examine whether altered hippocampal-neocortical functional connectivity correlates with memory impairment. A secondary aim was to explore if these connectivity changes are present 6 months after ECT.

METHODS

In-patients with severe depression (n = 35) received bitemporal ECT. Functional connectivity of the hippocampus was probed with resting-state fMRI before the first ECT-session, after the end of ECT, and at a six-month follow-up. Memory was assessed with the Verbal Learning Test - Delayed Recall. Seed-based connectivity analyses established connectivity of four hippocampal seeds, covering the anterior and posterior parts of the right and left hippocampus.

RESULTS

Compared to baseline, three of four hippocampal seeds became less connected to the core nodes of the posterior DMN in the week after ECT with Cohen's d ranging from -0.9 to -1.1. At the group level, patients showed post-ECT memory impairment, but individual changes in delayed recall were not correlated with the reduction in hippocampus-DMN connectivity. At six-month follow-up, no significant hippocampus-DMN reductions in connectivity were evident relative to pre-ECT, and memory scores had returned to baseline.

CONCLUSION

ECT leads to a temporary disruption of functional hippocampus-DMN connectivity in patients with severe depression, but the change in connectivity strength is not related to the individual memory impairment.

Cortical excitation/inhibition ratios in patients with major depression treated with electroconvulsive therapy: an EEG analysis

Electroconvulsive therapy (ECT) is an effective treatment for major depression, but its working mechanisms are poorly understood. Modulation of excitation/inhibition (E/I) ratios may be a driving factor. Here, we estimate cortical E/I ratios in depressed patients and study whether these ratios change over the course of ECT in relation to clinical effectiveness. Five-minute resting-state electroencephalography (EEG) recordings of 28 depressed patients were recorded before and after their ECT course. Using a novel method based on critical dynamics, functional E/I (fE/I) ratios in the frequency range of 0.5-30 Hz were estimated in frequency bins of 1 Hz for the whole brain and for pre-defined brain regions. Change in Hamilton Depression Rating Scale (HDRS) score was used to estimate clinical effectiveness. To account for test-retest variability, repeated EEG recordings from an independent sample of 31 healthy controls (HC) were included. At baseline, no differences in whole brain and regional fE/I ratios were found between patients and HC. At group level, whole brain and regional fE/I ratios did not change over the ECT course. However, in responders, frontal fE/I ratios in the frequencies 12-28 Hz increased significantly (pFDR < 0.05 [FDR = false discovery rate]) over the ECT course. In non-responders and HC, no changes occurred over time. In this sample, frontal fE/I ratios increased over the ECT course in relation to treatment response. Modulation of frontal fE/I ratios may be an important mechanism of action of ECT.

Is the Electroconvulsive Therapy Video on YouTube Supportive Information for Patients and Their Primary Caregivers?

BACKGROUND

Electroconvulsive therapy (ECT) is a significant contemporary medical treatment modality for various mental disorders that have not responded to other treatments. YouTube is a valuable place to get health-related educational content that can have a big impact on patients' and their primary caregivers' behaviors and decisions.

OBJECTIVE

The aim of the study is to analyze the content of YouTube videos related to ECT to investigate the quality and reliability of videos as supportive information for patients and their primary caregivers.

METHODS

A total of 250 videos related to ECT that are available on YouTube were analyzed. The Global Quality Scale and the modified DISCERN tool were used to assess the quality and reliability of the videos. Details of the content of the video, caregiver appearance, methods of information presentation, source of the video, and video parameters were analyzed as well.

RESULT

The analysis revealed that the median total score of Global Quality Scale was 3 (interquartile range, 2; min-max, 1-5), which means the video quality was medium. The median total score of the modified DISCERN tool was 3 (interquartile range, 1; min-max, 0-5), which means the videos were highly reliable. Most of the video sources in the included videos were educational (41.2%, n = 103) from formal caregivers, and there was no significant difference between Global Quality Scale scores, video parameters, and modified DISCERN scores.

CONCLUSIONS

YouTube is considered a supportive source of information related to ECT but needs more encouragement from formal caregivers to disseminate high-quality and reliable healthcare content on YouTube platforms to ensure access to accurate information.

Perceived Barriers to Using Neurostimulation: A National Survey of Psychiatrists, Patients, Caregivers, and the General Public

OBJECTIVES

Neurostimulation interventions often face heightened barriers limiting patient access. The objective of this study is to examine different stakeholders' perceived barriers to using different neurostimulation interventions for depression.

METHODS

We administered national surveys with an embedded experiment to 4 nationwide samples of psychiatrists (n = 505), people diagnosed with depression (n = 1050), caregivers of people with depression (n = 1026), and members of the general public (n = 1022). We randomly assigned respondents to 1 of 8 conditions using a full factorial experimental design: 4 neurostimulation modalities (electroconvulsive therapy [ECT], repetitive transcranial magnetic stimulation [rTMS], deep brain stimulation [DBS], or adaptive brain implants [ABIs]) by 2 depression severity levels (moderate or severe). We asked participants to rank from a list what they perceived as the top 3 barriers to using their assigned intervention. We analyzed the data with analysis of variance and logistic regression.

RESULTS

Nonclinicians most frequently reported "limited evidence of the treatment's effectiveness" and "lack of understanding of intervention" as their top 2 most important practical barriers to using ECT and TMS, respectively. Compared with nonclinicians, psychiatrists were more likely to identify "stigma about treatment" for ECT and "lack of insurance coverage" for TMS as the most important barriers.

CONCLUSIONS

Overall, psychiatrists' perceptions of the most important barriers to using neurostimulation interventions were significantly different than those of nonclinicians. Perceived barriers were significantly different for implantable DBS and ABI) versus nonimplantable (rTMS and ECT) neurostimulation interventions. Better understanding of how these barriers vary by neurostimulation and stakeholder group could help us address structural and attitudinal barriers to effective use of these interventions.

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.

Electroconvulsive Therapy in the United States: A 2022 Survey of Practice

OBJECTIVES

This study aimed to describe current US electroconvulsive therapy (ECT) practice, identify practice changes over time, and inform discussion of practice.

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 1 survey per ECT site. We examined frequency of responses, tabulated individual comments, and grouped data for comparison.

RESULTS

We received responses from 74 US practice sites encompassing 283 providers. Forty-nine percent (n = 36) of respondents practiced at general academic medical centers, 23% (n = 17) at general medical centers, 16% (n = 12) at freestanding psychiatric hospitals, and 7% (n = 5) at Veterans Affairs medical centers. Proportions of female (29%) and Black or African American (AA) (1%) ECT providers were markedly lower than proportions of female (60%) and Black or African American ECT patients (10%). The median number of treatments for a major depressive episode was 10. The preferred electrode placement was right unilateral (66%, n = 45). The favored dosing strategy was seizure threshold titration. Quantitative outcome measures were used by 89% (n = 66) of sites for depressive symptoms and 84% (n = 62) for cognitive adverse effects.

CONCLUSIONS

This survey is the first nationwide survey of ECT practice in nearly 40 years. Our results describe changes in practice over time and highlight the need to increase the number of female and Black or African American ECT providers. A comprehensive network of ECT sites could facilitate more frequent nationwide surveys.

The efficacy of electroconvulsive therapy in adolescent major depressive disorder with suicidal ideation: A propensity score-matched, retrospective cohort study

BACKGROUND

More evidence is needed to validate the use of ECT in adolescent depression. This study aims to compare the effectiveness of electroconvulsive therapy (ECT) to conventional medication therapy for adolescents with major depression with suicidal ideation.

METHODS

In this retrospective cohort study, we reviewed inpatient records from the First Affiliated Hospital of Chongqing Medical University spanning December 2016 to June 2021. We focused on adolescents diagnosed with severe depression presenting with suicidal tendencies. To equalize baseline differences between patients, we used the one-to-one propensity score matching to match patients who received ECT treatment with those who did not. Multivariate regression analysis was utilized to adjust for potential confounders, and subgroup analyses and sensitivity analyses were conducted to verify the robustness of our findings.

RESULTS

Of the 626 patients in this study, 474 underwent ECT treatment while 152 received medication treatment, all aged between 10 and 18 years. Once matched, each group contained 143 patients. The ECT group demonstrated a significantly higher response rate and greater reductions in both Hamilton Depression Rating Scale and Hamilton Anxiety Scale scores (all P < 0.001). Additionally, the ECT group was more effective in reducing suicidal ideation, with fewer individuals retaining such ideation at discharge. In the multivariable regression analysis, both ECT treatment and shorter disease duration were independently linked to enhanced antidepressant efficacy. Subgroup analyses and sensitivity analyses verified the robustness of the main study effect.

CONCLUSIONS

For adolescents with major depressive disorder and suicidal ideation, combining ECT with pharmacotherapy is more effective than pharmacotherapy alone before medications reach full effect.