Abstract
Purpose of the Review:
Magnetic seizure therapy (MST) is a novel neurostimulation method that merges the benefits of controlled seizure induction with the targeted application and enhances the safety of magnetic stimulation. This article reviews current research and assesses the potential role of MST in the management of mood disorders.
Collection and Analysis of Data:
We searched PubMed and Google Scholar for English-language articles on MST in mood disorders. We also searched for articles comparing MST with electroconvulsive therapy. Early clinical studies and preclinical studies suggest that MST may be effective in alleviating both manic and depressive symptoms, with a more favorable cognitive profile. However, evidence remains preliminary, with limited randomized controlled trials and comprehensive long-term follow-up data.
Conclusion:
Although MST appears promising as an innovative treatment option, additional large-scale, rigorously controlled studies are needed to confirm its safety, effectiveness, and ideal therapeutic approaches for individuals with mood disorders.
The possibility that transcranial magnetic stimulation (TMS) can elicit seizures has been acknowledged. The hypothesis posited that combining subconvulsive doses of repeated transcranial magnetic stimulation (rTMS) with the antidepressant effects of electroconvulsive therapy (ECT) would yield more favorable outcomes than either treatment administered individually. In 1998, initial experiments to induce seizures using magnetic methods were conducted on Rhesus monkeys, followed by trials on other nonhuman primates.
The first human trial of magnetic seizure therapy (MST) was conducted in 2001 in Bern, Switzerland, and was supervised by Lisanby et al. This innovative approach explores the potential combined effects of TMS and ECT to enhance treatment outcomes for individuals with depression. 1 The therapeutic method of MST exhibits similarities to that of ECT. A comprehensive evaluation is undertaken, including assessments of psychiatric, neurological, and medical factors, as well as a full mental status examination (MSE). A thorough neurocognitive examination is conducted. Due to its convulsive nature, the administration of MST is constantly performed under the supervision of general anesthesia. 2 The dose of MST is individualized for each patient based on assessment of their unique seizure threshold. The procedure entails a steady escalation of MST stimulation duration until discernible limb motor activity with the cuff and evidence of ictal electroencephalogram (EEG) activity are achieved.
To date, evidence exists for the utility of MST for major depressive disorder (MDD) and suicidal ideations, but the data are still preliminary and do not bear US-FDA approval for the same or mention in any standard treatment guidelines. Here, we briefly discuss the putative role of MST for bipolar disorder and the surrounding aspects, and how it compares with ECT on various agendas.
Bipolar disorder is marked by episodes of hypomania or mania alongside episodes of depression, which come with significant impairment and burden. 3 Among patients with bipolar disorder, major depressive episodes occur more frequently and last longer than manic or hypomanic episodes. Recovery rates following depressive episodes are significantly lower compared to manic episodes. Bipolar depression is 1.6 times more resistant to treatment and has a 3.4 times higher relapse rate after successful treatment than unipolar depression. These factors highlight the complexity and challenges of managing bipolar disorder, mainly due to the substantial impact and recurrence of depressive episodes. 4 Recovery rates are notably higher for manic episodes compared to depressive episodes. 5 ECT is considered among the most effective interventions for bipolar disorder, with remission rates reported as high as 85%. 6
Methods
Search Strategy
Two authors independently searched MEDLINE (PubMed) and Google Scholar from 2001 to July 2024. A Boolean search was conducted using a combination of the following MeSH and text terms: “Magnetic seizure therapy,” “bipolar disorder,” “bipolar affective disorder,” “mania,” “depression,” and “electroconvulsive therapy.”
We limited our search to English-language studies on adult patients (18 years and above) that assessed the efficacy and tolerability of MST in any psychiatric disorder, and especially in mood disorders. Further, while unipolar depressive disorder is a different entity to bipolar depressive disorder, including all studies on depressive disorder in our review is done as certain characteristics of depression are often retained irrespective of unipolar v/s bipolar and hence, reviewing such studies can give us overall clues to the use of MST in bipolar depression until we have extensive and robust literature available in this field.
Results
The key clinical studies evaluating the efficacy, stimulation parameters, outcomes, and cognitive effects of magnetic seizure therapy (MST) in mood disorders are summarized in Table 1. A total of 11,271 articles on MST were indexed in PubMed. A combination of search terms of “magnetic seizure therapy” and “bipolar disorder” revealed 57 results, and finally, the combination of “magnetic seizure therapy” and “depression” revealed 478 results. After screening titles and abstracts, 22 articles were included in our review. A total of four articles were included for Bipolar affective disorder, two articles on bipolar depression, seven articles on depression, and treatment-resistant depression.
Summary of Clinical Studies Evaluating MST in Mood Disorders.
ECT: Electroconvulsive therapy; MST: Magnetic seizure therapy.
Discussion
ECT Versus MST
MST represents an innovative convulsive neuromodulation technique that merges the targeted precision of TMS with the therapeutic seizure induction of ECT. Using a specialized high-output magnetic coil, MST focuses rapid magnetic pulses through the scalp and skull to generate controlled seizures under general anesthesia with muscle relaxation, mirroring the procedural setup of ECT but replacing direct electrical stimulation with magnetic induction. MST shares many procedural similarities with ECT, including the need for comparable pre-treatment setup and infrastructure. Still, it is delivered via a modified, high-powered TMS device capable of much higher output than standard TMS systems. Performed under general anesthesia with muscle relaxation, MST induces a therapeutic seizure as its primary mechanism of action. Notably, MST-generated seizures tend to elicit less parasympathetic activation and a smaller serum prolactin surge than ECT, reflecting reduced subcortical spread. At present, two MST devices are available commercially: the MagPro MST by MagVenture (MagPro R30/X100 adapted for MST) and the MagStim MST system. Both are optimized for controlled seizure induction through high-frequency magnetic stimulation. 1 ECT is typically used as a second-line option for individuals with mania who have not responded sufficiently to initial monotherapy. 7 Its application in bipolar mania is limited by concerns about possible side effects, such as cognitive impairment, as well as the stigma surrounding the treatment. Instead of electrical currents, it employs magnetic pulses in patients under general anesthesia. Magnetic pulses pass through the skull without obstruction, enabling precise targeting of cortical areas. 8 This precision helps reduce cognitive adverse effects. 9 In addition, individuals receiving MST typically demonstrate faster reorientation, less cognitive disruption, and a more rapid recovery than patients treated with ECT.10–13 Aperiodic activity is observed on the EEG after MST, indicating the absence of a regular, repeating pattern or rhythmic oscillations. It represents non-oscillatory brain signals and is often contrasted with periodic or oscillatory activities, such as alpha, beta, theta, or delta waves, which have clear, repeating cycles. After MST, EEG often shows periods of aperiodic slowing, particularly as delta or theta waves, which do not follow regular oscillatory patterns but instead exhibit irregular fluctuations. This slowing reflects reduced cortical excitability or recovery from the induced seizure. MST, compared with ECT, generally induces less pronounced aperiodic activity. This is because MST employs more focused magnetic stimulation, which tends to produce shorter, less intense seizures. As a result, the brain’s recovery, reflected in its EEG activity, tends to be faster, with aperiodic patterns transitioning back to periodic rhythms more quickly than after ECT. 14
MST in Bipolar Disorder
Bipolar mania is a prevalent and disabling mental illness marked by an irritable or persistently elevated mood, as well as abnormally increased activity or energy. A randomized controlled trial (RCT) took place at the Shanghai Mental Health Center from July 1, 2017 to April 26, 2021. A total of 48 patients with bipolar mania were enrolled and randomly allocated to receive either MST or ECT. Participants attended 2 to 3 sessions per week, for a total of 8 to 10 sessions. MST was delivered at the maximum device output (75 Hz) over the vertex. The findings demonstrated a decrease in total Young Mania Rating Scale (YMRS) scores and response rates, defined as a greater than 50% reduction from baseline. The MST group experienced fewer cognitive impairments compared to the ECT group. 13 However, the small sample size limited the study’s ability to clearly identify clinically meaningful differences in response rates between the two treatments. Nonetheless, the results indicate that MST could be a promising alternative for managing bipolar mania. Further research with larger participant groups, extended follow-up, and diverse MST protocols is necessary to establish its effectiveness and expand its clinical use. In their commentary, Nordenskjöld et al. review a randomized trial comparing MST and ECT for bipolar mania. Both treatments produced high response rates, highlighting MST’s potential as an alternative to ECT. Importantly, MST was associated with better preservation of language abilities, suggesting a more favorable cognitive side-effect profile than ECT. The authors emphasize the necessity for larger, well-powered studies to confirm MST’s efficacy and safety before it can be considered a replacement for ECT. 15 The study by Noda et al. reports two cases where patients undergoing MST for treatment-resistant depression developed acute manic symptoms after the sixth MST session. In contrast, patient 2 did so after the 23rd session. In both instances, the MST treatment was halted, and the manic symptoms resolved promptly with pharmacological intervention. The authors conclude that, similar to ECT, MST carries a risk of inducing mania or hypomania, and clinicians should monitor such mood symptoms. 16 A study by Kayser et al. found that MST resulted in a significant reduction in depressive symptoms. The patient experienced no subjective cognitive side effects and regained full orientation more rapidly than typically observed with ECT. MST-induced seizures were shorter in duration, exhibited lower EEG amplitude, and had less pronounced postictal suppression compared to those induced by ECT. These findings suggest that MST may offer antidepressant benefits comparable to ECT but with a more favorable cognitive side-effect profile. 17
MST in Depression
Depression ranks among the leading causes of mortality. In a study led by Zhi-De Deng and colleagues, the efficacy and side effects of MST were compared to those of ECT in individuals experiencing major depressive episodes. The objective was to assess whether MST, which uses magnetic fields to induce seizures in a more targeted manner, could provide similar antidepressant benefits to ECT while minimizing the cognitive side effects commonly linked to ECT. The researchers conducted a randomized clinical trial with patients diagnosed with MDD, assigning them randomly to receive either MST or ECT. Both treatment groups underwent multiple sessions, and outcomes such as the severity of depression, cognitive performance, and seizure characteristics (including seizure duration) were evaluated.
ECT demonstrated greater effectiveness in achieving antidepressant response and remission, leading to higher improvement rates among patients with severe depression. MST also demonstrated antidepressant effects, though the response was generally slightly lower compared to ECT. However, MST showed promise as an alternative treatment, particularly for individuals who may be unable to tolerate ECT. MST had a clear advantage with respect to cognitive side effects, particularly memory impairment. Patients who underwent MST experienced less post-treatment amnesia and better-preserved cognitive function compared to those treated with ECT. ECT was associated with greater cognitive deficits, particularly in memory and language, consistent with prior studies on ECT. MST induces shorter, more focal seizures than ECT, consistent with MST’s targeted stimulation approach, which may account for its lower cognitive impact. 11
MST in Treatment-resistant Depression
The CREST-MST study, led by Zafiris J. Daskalakis, was a clinical trial aimed at assessing the efficacy and safety of MST versus ECT in patients with MDD. This study was part of the Clinical Research Study for MST (CREST-MST) program, which aimed to determine whether MST, a non-invasive neuromodulation therapy, could serve as a safer alternative to ECT for individuals with treatment-resistant depression. The focus was on comparing the antidepressant efficacy, cognitive side effects, and seizure characteristics between MST and ECT.
Individuals with MDD were randomly assigned to receive either MST or ECT. The trial involved multiple treatment sessions for both MST and ECT, with seizure duration and clinical outcomes being closely monitored. Cognitive effects, particularly memory impairment, were also assessed post-treatment. ECT demonstrated higher rates of clinical response and remission compared to MST. However, MST still showed promising antidepressant effects, though slightly less potent than ECT.
MST had a significant advantage in terms of cognitive side effects. Patients who received MST showed less cognitive impairment, particularly in memory and attention, than those treated with ECT. This was one of the key benefits of MST over ECT, suggesting it may be more tolerable for patients concerned about cognitive side effects.
MST-induced seizures were shorter and more focal compared to the generalized seizures seen with ECT. The study supported the notion that MST could provide a balanced treatment option, offering antidepressant benefits with reduced cognitive side effects. 18
MST in Children and Adolescents
Major depression in adolescence is a significant public health issue, affecting 2.5%–8% of adolescents. It is linked to numerous negative outcomes, including an increased risk of suicide, poor academic performance, impaired social skills, social withdrawal, and substance abuse. MST has shown efficacy in adult patients with treatment-resistant depression, without significant memory impairment.
Noda et al. reported the first successful application of MST in treating an adolescent with treatment-resistant bipolar depression. In this ongoing open-label study on treatment-resistant major depression, the patient underwent MST using a twin coil device, with each coil positioned over the frontal cortex at F3 and F4. MST was administered at 100 Hz and 100% machine output, with progressively increasing train durations. Depressive symptoms were assessed using the 24-item Hamilton Depression Rating Scale, and cognitive functions were evaluated with a comprehensive neuropsychological battery. After 18 MST sessions, the adolescent patient experienced complete remission of clinical symptoms and did not exhibit any significant cognitive decline, aside from some autobiographical memory impairment, which may or may not be associated with MST. This case report indicates that MST may be a safe and well-tolerated treatment option for adolescents with treatment-resistant bipolar depression. 19
Although MST appears promising for treating certain psychiatric and neurological disorders in children and adolescents, additional research is necessary to thoroughly establish its effectiveness, safety, and overall role in this population. Close collaboration between researchers, clinicians, and ethicists is crucial to ensure MST is used responsibly and effectively in pediatric patients.
Adverse Effects of MST
Common adverse effects associated with MST include headache, dizziness, nausea, muscle aches, and fatigue. These symptoms may result from the anesthesia used during the procedure or from the MST itself. Additionally, there is a risk of hearing loss from the clicking produced by the magnetic coils, though this can be mitigated by using earplugs. 1 More concerning are the potential neuropsychiatric side effects. There have been instances of mania induced by MST in patients undergoing treatment for major depressive episodes, underscoring the importance of close monitoring throughout the therapy. Moreover, while MST is designed to minimize cognitive side effects, some studies have noted a decline in autobiographical memory following treatment. 16
Critical Appraisal of Existing Literature
The existing research on MST in bipolar disorder is still in its nascent stages. The lack of longitudinal data complicates the evaluation of long-term efficacy and safety. Variability in stimulation parameters (e.g., coil type, seizure-threshold protocols) and patient characteristics hampers inter-study comparisons. Furthermore, although cognitive outcomes are typically positive, they are not uniformly evaluated using conventional neuropsychological testing. The scarcity of research on manic episodes further constrains comprehension of MST’s function within the whole spectrum of bipolar disease.
There are also areas of potential bias that should be noted. Numerous studies examining MST in bipolar disorder are constrained by smaller sample sizes, open-label methodologies, and a relative absence of RCTs. This presents hazards of selection bias, placebo effects, and observer bias. Additionally, many early trials combine patients with unipolar and bipolar depression, making it challenging to distinguish the specific effects of MST on bipolar disorder. Publication bias may distort available data in favor of favorable outcomes, as studies with null or negative results are less frequently reported.
To verify MST as a therapy option, large-scale, double-blind, RCTs specifically focused on bipolar disorder are essential. These studies must incorporate long-term follow-up, standardized cognitive evaluations, and distinct analyses for manic and depressed phases. Formulating agreement criteria on treatment settings and safety monitoring will be essential.
MST is still considered an experimental treatment for bipolar disorder and other mood disorders. The current body of research, which mainly consists of open-label studies and small case reports, indicates that MST may help alleviate depressive symptoms with fewer cognitive side effects than ECT. However, the evidence to date remains limited and preliminary. Studies vary widely in stimulation frequency, coil placement, and titration protocols, which makes meaningful comparisons across trials difficult. Cognitive assessments, though often considered safe, lack consistency in the instruments used and are rarely applied uniformly across studies. MSTefficacy in manic episodes is virtually unexplored, and many trials combine bipolar and unipolar depression into aggregated samples, preventing precise analysis of MST’s effects specific to bipolar disorder.
Because most MST research has involved small cohorts without sham or control arms, concerns around selection bias, observer bias, and placebo effects cannot be ignored. Publication bias is also a significant concern, as positive results are overrepresented, and negative or null findings may not be reported. Without larger, randomized, double-blind studies, there is insufficient evidence to know how reliably MST works or how durable its effects may be. Ultimately, to establish the therapeutic value and safety of MST, larger and rigorously designed studies are needed that focus exclusively on bipolar disorder, encompass both depressive and manic episodes, utilize standardized cognitive assessments, and include long-term follow-up. These gaps highlight the need for rigor and consistency in future research, and underscore why MST cannot yet be recommended as a standard treatment outside of controlled clinical settings.
Conclusions
MST is an emerging non-invasive neuromodulation approach that has shown antidepressant benefits with comparatively mild neurocognitive side effects. However, progress in its development has been gradual, given its status as a novel technology. Continued research is essential to replicate and validate encouraging findings from computational models, preclinical work, and clinical studies, especially in the contexts of unipolar depression, bipolar depression, and schizophrenia. Due to its ability to provide spatially precise stimulation, MST can potentially translate response biomarkers from ECT into more targeted and personalized treatments. This could enhance its use across various mental health conditions.
Supplemental Material
Supplemental material for this article available online.
Footnotes
Acknowledgements
Nil.
Reporting Guideline (Supplementary Online material): Narrative Review Checklist
Green BN, Johnson CD and Adams A. Writing narrative literature reviews for peer-reviewed journalsecrets of the trade. J Sports Chiropr Rehabil 2001; 15: 5–19.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
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References
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