Safety and feasibility of magnetic seizure therapy (MST) in major depression: randomized within-subject comparison with electroconvulsive therapy

Applications of transcranial magnetic stimulation and magnetic seizure therapy in the study and treatment of disorders related to cerebral aging

Transcranial magnetic stimulation (TMS) can be used to probe cortical function and treat neuropsychiatric illnesses. TMS has demonstrated neuroplastic effects akin to long-term potentiation and long-term depression, and therapeutic applications are in development for post-stroke recovery, Alzheimer's disease, and depression in seniors. Here, we discuss two new directions of TMS research relevant to cerebral aging and cognition. First, we introduce a paradigm for enhancing cognitive reserve, based on our research in sleep deprivation. Second, we discuss the use of magnetic seizure therapy (MST) to spare cognitive functions relative to conventional electroconvulsive therapy, and as a means of providing a more potent antidepressant treatment when subconvulsive TMS has shown modest efficacy in seniors. Whether in the enhancement of cognition as a treatment goal, or in the reduction of amnesia as a side effect, these approaches to the use of TMS and MST merit further exploration regarding their clinical potential.

What is the role of brain stimulation therapies in the treatment of depression?

Brain stimulation therapies have demonstrated efficacy in the treatment of depression and treatment-resistant depression (TRD). Non-invasive brain stimulation in the treatment of depression has grown substantially due to their favorable adverse effect profiles. The role of transcranial direct current stimulation in TRD is unclear, but emerging data suggests that it may be an effective add-on treatment. Repetitive transcranial magnetic stimulation has demonstrated efficacy in TRD that is supported by several multicenter randomized controlled trials. Though, vagus nerve stimulation has been found to be effective in some studies, sham controlled studies were equivocal. Electroconvulsive therapy (ECT) is a well-established brain stimulation treatment for severe depression and TRD, yet stigma and cognitive adverse effects limit its wider use. Magnetic seizure therapy has a more favorable cognitive adverse effect profile; however, equivalent efficacy to ECT needs to be established. Deep brain stimulation may play a role in severe TRD and controlled trials are now underway.

Effect of magnetic seizure therapy on regional brain glucose metabolism in major depression

Currently electroconvulsive therapy (ECT) is one of the only available therapies for treatment resistant depression (TRD). While effective, ECT is complicated by side effects, including cognitive impairment. One promising potential alternative is magnetic seizure therapy (MST). To date, no research has explored the effects of 100Hz MST on brain activity or the brain changes associated with response to treatment. Therefore the aim of this study was to determine the effects of a treatment course of 100Hz MST on regional brain glucose metabolism. Ten patients with treatment resistant depression underwent positron emission tomography with fluorodeoxyglucose before and after a treatment course of MST. Changes in the relative metabolic rate of a priori brain regions were investigated. Areas of increased relative metabolism after treatment were seen in the basal ganglia, orbitofrontal cortex, medial frontal cortex and dorsolateral prefrontal cortex. A secondary analysis showed trend-level differential findings in brain activation between responders and non-responders, namely in the ventral anterior cingulate. These results primarily indicate that MST is affecting regions consistent with the limbic-cortical dysregulation model of depression. Exploratory analysis indicated some differential findings in brain activation between responders and non-responders were also evident; however, the small sample size precludes any firm conclusions.

Pilot study of the clinical and cognitive effects of high-frequency magnetic seizure therapy in major depressive disorder

BACKGROUND

Electroconvulsive therapy (ECT) is a very commonly used treatment for patients with severe and treatment-resistant depression. Although effective, this treatment is complicated by a number of side effects including cognitive impairment motivating attempts to develop treatment alternatives. Magnetic seizure therapy (MST) is a brain stimulation technique using a high-powered transcranial magnetic stimulation device to produce therapeutic seizures. Preliminary research suggests that MST has antidepressant activity in the absence of cognitive side effects. The aim of this study was therefore to investigate the therapeutic efficacy and cognitive profile of MST provided at high frequency (100 Hz) and potentially longer stimulation trains and longer treatment courses than have been previously investigated.

METHODS

Thirteen patients participated in an open-label clinical trial of up to 18 treatment sessions with 100-Hz MST. Assessments of depression severity and cognitive functioning were performed before and after treatment.

RESULTS

Of the 13 patients who completed the study, five met clinical response criteria at study end. There was an overall group reduction in depression severity and no evidence of any impairment of orientation, memory, or other elements of cognition after MST treatment. The major limitation of the study was its lack of sham control.

CONCLUSIONS

In conclusion, MST shows antidepressant efficacy without apparent cognitive side effects. However, substantial research is required to understand the optimal conditions for stimulation and to compare MST to established treatments including ECT.

Disruption of component processes of spatial working memory by electroconvulsive shock but not magnetic seizure therapy

Self-ordered spatial working memory measures provide important information regarding underlying cognitive strategies, such as stereotypy. This strategy is based on repetitive sequential selection of a spatial pattern once a correct sequence has been identified. We previously reported that electroconvulsive shock (ECS) but not magnetic seizure therapy (MST) impaired performance on a spatial working memory task in a preclinical model. Here we tested the hypothesis that ECS disrupted stereotyped patterns in the selection of spatial stimuli. In a within-subject study design, we assessed the effects of ECS, MST, and sham on stereotypy and reaction time in a preclinical model. Stereotypy was assessed by the correlation of actual and predicted response patterns of spatial stimuli. Predicted patterns were based on performance during baseline sessions. ECS resulted in lower correlations between predicted and actual responses to spatial stimuli in two of the three subjects, and it also disrupted stereotypy. For one subject, there was change in the predictability of the spatial locus of responses between experimental conditions. For all three subjects, reaction time was significantly longer in ECS, relative to MST and sham. This is the first study to examine the effect of ECS, and to contrast the effects of ECS and MST, on spatial working memory component processes. Our preliminary findings show that ECS, but not MST decreased stereotypy and increased reaction time. This line of investigation may have significant implications in our understanding cognitive component processes of memory function and impairment.

Transcranial electric and magnetic stimulation: technique and paradigms

Transcranial electrical and magnetic stimulation techniques encompass a broad physical variety of stimuli, ranging from static magnetic fields or direct current stimulation to pulsed magnetic or alternating current stimulation with an almost infinite number of possible stimulus parameters. These techniques are continuously refined by new device developments, including coil or electrode design and flexible control of the stimulus waveforms. They allow us to influence brain function acutely and/or by inducing transient plastic after-effects in a range from minutes to days. Manipulation of stimulus parameters such as pulse shape, intensity, duration, and frequency, and location, size, and orientation of the electrodes or coils enables control of the immediate effects and after-effects. Physiological aspects such as stimulation at rest or during attention or activation may alter effects dramatically, as does neuropharmacological drug co-application. Non-linear relationships between stimulus parameters and physiological effects have to be taken into account.

Neuromodulation for treatment-resistant depression

Treatment-resistant depression affects at least 1-3% of the US population. This article reviews the current state of focal neuromodulation therapies for treatment-resistant depression, focusing on those treatments published clinical data. These include transcranial magnetic stimulation, transcranial direct current stimulation, magnetic seizure therapy, vagus nerve stimulation, direct cortical stimulation, and deep brain stimulation among others. Of these, only two (transcranial magnetic stimulation and vagus nerve stimulation) currently have US Food and Drug Administration approval for the treatment of depression.

Deep brain stimulation for treatment-resistant depression: efficacy, safety and mechanisms of action

Deep brain stimulation (DBS), a neuromodulation therapy that has been used successfully in the treatment of symptoms associated with movement disorders, has recently undergone clinical trials for individuals suffering from treatment-resistant depression (TRD). Although the small patient numbers and open label study design limit our ability to identify optimum targets and make definitive conclusions about treatment efficacy, a review of the published research demonstrates significant reductions in depressive symptomatology and high rates of remission in a severely treatment-resistant patient group. Despite these encouraging results, an incomplete understanding of the mechanisms of action underlying the therapeutic effects of DBS for TRD is highlighted, paralleling the incomplete understanding of the neuroanatomy of mood regulation and treatment resistance. Proposed mechanisms of action include short and long-term local effects of stimulation at the neuronal level, to modulation of neural network activity.

[Brain stimulation procedures. Transcranial magnetic stimulation, magnetic seizure therapy and deep brain stimulation]

Brain stimulation methods are promising treatment options in severe treatment-resistant psychiatric disorders. A safe and noninvasive method is transcranial magnetic stimulation, but the clinical application is not clear. Magnetic seizure therapy is a further development of transcranial magnetic stimulation, by which generalized seizures are induced under anaesthesia. Previous results with regard to the antidepressant effects and the fewer cognitive side effects were significant. Deep brain stimulation is an invasive procedure in which electrodes are stereotactically implanted in special brain areas. The effects in severe therapy-resistant obsessive-compulsive disorders and depressions are promising. However, the evaluation of ethical issues remains an important task.

Magnetic seizure therapy for treatment-resistant depression

Approximately 30% of people with depression do not respond to standard treatments. Currently, the standard treatment for patients with treatment-resistant depression is electroconvulsive therapy (ECT). ECT, while effective, has a number of common side effects that limit its use - in particular the occurrence of memory impairment. As such, there has been a considerable degree of research effort directed at developing a treatment for treatment-resistant depression that retains the efficacy of ECT but limits the unwanted cognitive side effects. This research has involved modifications to ECT itself, as well as the development of novel brain stimulation methods. Most recently, magnetic seizure therapy (MST) has been developed and trialed with promising results. This article explores the development of MST, as well as providing a discussion of the clinical and practical issues of the use of MST for the treatment of depression.

Somatic treatments for mood disorders

Somatic treatments for mood disorders represent a class of interventions available either as a stand-alone option, or in combination with psychopharmacology and/or psychotherapy. Here, we review the currently available techniques, including those already in clinical use and those still under research. Techniques are grouped into the following categories: (1) seizure therapies, including electroconvulsive therapy and magnetic seizure therapy, (2) noninvasive techniques, including repetitive transcranial magnetic stimulation, transcranial direct current stimulation, and cranial electric stimulation, (3) surgical approaches, including vagus nerve stimulation, epidural electrical stimulation, and deep brain stimulation, and (4) technologies on the horizon. Additionally, we discuss novel approaches to the optimization of each treatment, and new techniques that are under active investigation.

The emerging use of brain stimulation treatments for psychiatric disorders

OBJECTIVE

The aim of this study was to review the current state of development and application of a wide range of brain stimulation approaches in the treatment of psychiatric disorders.

METHOD

The approaches reviewed include forms of minimally invasive magnetic and electrical stimulation, seizure induction, implanted devices and several highly novel approaches in early development.

RESULTS

An extensive range of brain stimulation approaches are now being widely used in the treatment of patients with psychiatric disorders, or actively investigated for this use. Both vagal nerve stimulation (VNS) and repetitive transcranial magnetic stimulation (rTMS) have been introduced into clinical practice in some countries. A small body of research suggests that VNS has some potentially long-lasting antidepressant effects in a minority of patients treated. rTMS has now been extensively investigated for over 15 years, with a large body of research now supporting its antidepressant effects. Further rTMS research needs to focus on defining the most appropriate stimulation methods and exploring its longer term use in maintenance protocols. Very early data suggest that magnetic seizure therapy (MST) has promise in the treatment of patients referred for electroconvulsive therapy: MST appears to have fewer side effects and may have similar efficacy. A number of other approaches including surgical and alternative forms of electrical stimulation appear to alter brain activity in a promising manner, but are in need of evaluation in more substantive patient samples.

CONCLUSIONS

It appears likely that the range of psychiatric treatments available for patients will grow over the coming years to progressively include a number of novel brain stimulation techniques.

Brain stimulation in posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is a complex, heterogeneous disorder that develops following trauma and often includes perceptual, cognitive, affective, physiological, and psychological features. PTSD is characterized by hyperarousal, intrusive thoughts, exaggerated startle response, flashbacks, nightmares, sleep disturbances, emotional numbness, and persistent avoidance of trauma-associated stimuli. The efficacy of available treatments for PTSD may result in part from relief of associated depressive and anxiety-related symptoms in addition to treatment of core symptoms that derive from reexperiencing, numbing, and hyperarousal. Diverse, heterogeneous mechanisms of action and the ability to act broadly or very locally may enable brain stimulation devices to address PTSD core symptoms in more targeted ways. To achieve this goal, specific theoretical bases derived from novel, well-designed research protocols will be necessary. Brain stimulation devices include both long-used and new electrical and magnetic devices. Electroconvulsive therapy (ECT) and Cranial electrotherapy stimulation (CES) have both been in use for decades; transcranial magnetic stimulation (TMS), magnetic seizure therapy (MST), deep brain stimulation (DBS), transcranial Direct Current Stimulation (tDCS), and vagus nerve stimulation (VNS) have been developed recently, over approximately the past twenty years. The efficacy of brain stimulation has been demonstrated as a treatment for psychiatric and neurological disorders such as anxiety (CES), depression (ECT, CES, rTMS, VNS, DBS), obsessive-compulsive disorder (OCD) (DBS), essential tremor, dystonia (DBS), epilepsy (DBS, VNS), Parkinson Disease (DBS), pain (CES), and insomnia (CES). To date, limited data on brain stimulation for PTSD offer only modest guidance. ECT has shown some efficacy in reducing comorbid depression in PTSD patients but has not been demonstrated to improve most core PTSD symptoms. CES and VNS have shown some efficacy in reducing anxiety, findings that may suggest possible utility in relieving PTSD-associated anxiety. Treatment of animal models of PTSD with DBS suggests potential human benefit. Additional research and novel treatment options for PTSD are urgently needed. The potential usefulness of brain stimulation in treating PTSD deserves further exploration.

The use of ECT and MST in treating depression

Electroconvulsive therapy (ECT) has been used clinically since 1938. Its most common use is in the treatment of depression: first line treatment where rapid recovery is a priority, but more frequently as an effective treatment for patients who do not respond to pharmacological and psychological approaches. Whilst it is widely hailed as an effective treatment, concerns about its effect on cognition remain. The development of magnetic seizure therapy (MST) over the past decade has attempted to devise a therapy with comparable efficacy to ECT, but without the associated cognitive side effects. The rationale for this is that MST uses magnetic fields to induce seizures in the cortex, without electrical stimulation of brain structures involved with memory. MST has been used successfully in the treatment of depression, yet there is a dearth of literature in comparison with ECT. We present a systematic review of the literature on ECT (from 2009-2011) and MST (from 2001-2011).

A systematic review of the neurocognitive effects of magnetic seizure therapy

Magnetic seizure therapy (MST) is a novel neurotherapeutic intervention in development for the treatment of major affective disorders. Like other neurotherapeutic strategies such as electroconvulsive therapy (ECT) or transcranial magnetic stimulation (TMS), a primary interest will be to monitor the associated neurocognitive effects. Thus, the purpose of this systematic review was to synthesize the available data on the neurocognitive effects of MST. The authors performed two independent literature searches with the following terms terms: MST, magnetic, magnetic seizure therapy, depression, neurocognition, cognitive, preclinical. We included in this review a total of eleven articles that mentioned MST and neurocognition in the abstract. The articles were divided into three methodological domains that included virtual computer simulations, preclinical studies, and clinical investigations. Collectively, the available evidence suggests MST has little to no adverse cognitive effects. Specifically, virtual computer simulations found the magnetic field was localized to grey matter, and preclinical studies found no neurocortical or neurocognitive sequelae. Clinical investigations found MST to be associated with rapid reorientation and intact anterograde and retrograde memory. Future investigations using translational methods are warranted to confirm these findings and to further determine the effects of MST on neurocognitive functions.

Transcranial magnetic brain stimulation: therapeutic promises and scientific gaps

Since its commercial advent in 1985, transcranial magnetic stimulation (TMS), a technique for stimulating neurons in the cerebral cortex through the scalp, safely and with minimal discomfort, has captured the imaginations of scientists, clinicians and lay observers. Initially a laboratory tool for neurophysiologists studying the human motor system, TMS now has a growing list of applications in clinical and basic neuroscience. Although we understand many of its effects at the system level, detailed knowledge of its actions, particularly as a modulator of neural activity, has lagged, due mainly to the lack of suitable non-human models. Nevertheless, these gaps have not blocked the therapeutic application of TMS in brain disorders. Moderate success has been achieved in treating disorders such as depression, where the U.S. Food and Drug Administration has cleared a TMS system for therapeutic use. In addition, there are small, but promising, bodies of data on the treatment of schizophrenic auditory hallucinations, tinnitus, anxiety disorders, neurodegenerative diseases, hemiparesis, and pain syndromes. Some other nascent areas of study also exist. While the fate of TMS as a therapeutic modality depends on continued innovation and experimentation, economic and other factors may be decisive.

Repetitive transcranial magnetic stimulator with controllable pulse parameters

The characteristics of transcranial magnetic stimulation (TMS) pulses influence the physiological effect of TMS. However, available TMS devices allow very limited adjustment of the pulse parameters. We describe a novel TMS device that uses a circuit topology incorporating two energy storage capacitors and two insulated-gate bipolar transistor (IGBT) modules to generate near-rectangular electric field pulses with adjustable number, polarity, duration, and amplitude of the pulse phases. This controllable pulse parameter TMS (cTMS) device can induce electric field pulses with phase widths of 10-310 µs and positive/negative phase amplitude ratio of 1-56. Compared to conventional monophasic and biphasic TMS, cTMS reduces energy dissipation up to 82% and 57% and decreases coil heating up to 33% and 41%, respectively. We demonstrate repetitive TMS trains of 3000 pulses at frequencies up to 50 Hz with electric field pulse amplitude and width variability less than the measurement resolution (1.7% and 1%, respectively). Offering flexible pulse parameter adjustment and reduced power consumption and coil heating, cTMS enhances existing TMS paradigms, enables novel research applications and could lead to clinical applications with potentially enhanced potency.

Antidepressant effects, of magnetic seizure therapy and electroconvulsive therapy, in treatment-resistant depression

Major depression is a common mental health problem and associated with significant morbidity and mortality, including impaired social and physical functioning and increased risk for suicide. Electroconvulsive therapy (ECT) is highly efficacious in treatment-resistant depressive disorders, but cognitive side effects are frequently associated with the treatment. Magnetic seizure therapy (MST) is a form of convulsive therapy, using magnetic fields in order to induce therapeutic seizures. First studies suggested that cognitive side effects of MST, including postictal recovery time, are more benign than those resulting from ECT treatment. In this open-label study we tested the hypothesis that MST is associated with clinically significant antidepressant effects in treatment-resistant depression (TRD) as an add-on therapy to a controlled pharmacotherapy. Twenty patients suffering from TRD were randomly assigned to receive either MST or ECT starting from July 2006 until November 2008. Primary outcome measure was antidepressant response assessed by Montgomery Åsberg Depression Scale. Secondary outcome measures included Hamilton Depression Rating Scale, Hamilton Anxiety Scale, Beck Depression Inventory and 90-Item Symptom Checklist. Antidepressant response (improvement of 50% in MADRS ratings) was statistically significant and of similar size in both treatment groups. Cognitive side effects were observed in neither group. Characteristics in MST- and ECT-induced seizures were comparable, especially regarding ictal activity and postictal suppression. Thus, MST may be a potential alternative to ECT if efficacy and safety are validated in larger clinical trials.

Electric field strength and focality in electroconvulsive therapy and magnetic seizure therapy: a finite element simulation study

We present the first computational study comparing the electric field induced by various electroconvulsive therapy (ECT) and magnetic seizure therapy (MST) paradigms. Four ECT electrode configurations (bilateral, bifrontal, right unilateral, and focal electrically administered seizure therapy) and three MST coil configurations (circular, cap, and double cone) were modeled. The model incorporated a modality-specific neural activation threshold. ECT (0.3 ms pulse width) and MST induced the maximum electric field of 2.1-2.5 V cm⁻¹ and 1.1-2.2 V cm⁻¹ in the brain, corresponding to 6.2-7.2 times and 1.2-2.3 times the neural activation threshold, respectively. The MST electric field is more confined to the superficial cortex compared to ECT. The brain volume stimulated was much larger with ECT (up to 100%) than with MST (up to 8.2%). MST with the double-cone coil was the most focal, and bilateral ECT was the least focal. Our results suggest a possible biophysical explanation of the reduced side effects of MST compared to ECT. Our results also indicate that the conventional ECT pulse amplitude (800-900 mA) is much higher than necessary for seizure induction. Reducing the ECT pulse amplitude should be explored as a potential means of diminishing side effects.

Neuropsychologic effects of neuromodulation techniques for treatment-resistant depression: a review

Electroconvulsive therapy (ECT) and ablative neurosurgical procedures are established interventions for treatment-resistant depression (TRD), but their use may be limited in part by neuropsychological adverse effects. Additional neuromodulation strategies are being developed that aim to match or exceed the efficacy of ECT/ablative surgery with a better neurocognitive side effect profile. In this review, we briefly discuss the neurocognitive effects of ECT and ablative neurosurgical procedures, then synthesize the available neurocognitive information for emerging neuromodulation therapies, including repetitive transcranial magnetic stimulation, magnetic seizure therapy, transcranial direct current stimulation, vagus nerve stimulation, and deep brain stimulation. The available evidence suggests these procedures may be more cognitively benign relative to ECT or ablative neurosurgical procedures, though further research is clearly needed to fully evaluate the neurocognitive effects, both positive and negative, of these novel neuromodulation interventions.

Advances in the Management of Treatment-Resistant Depression

Treatment-resistant depression (TRD) is a prevalent, disabling, and costly condition affecting 1%-4% of the U.S.

POPULATION

Current approaches to managing TRD include medication augmentation (with lithium, thyroid hormone, buspirone, atypical antipsychotics, or various antidepressant medications), psychotherapy, and ECT. Advances in understanding the neurobiology of mood regulation and depression have led to a number of new potential approaches to managing TRD, including medications with novel mechanisms of action and focal brain stimulation techniques. This review will define and discuss the epidemiology of TRD, review the current approaches to its management, and then provide an overview of several developing interventions.

Objective cognitive performance associated with electroconvulsive therapy for depression: a systematic review and meta-analysis

BACKGROUND

Electroconvulsive therapy (ECT) is the most acutely effective treatment for depression, but is limited by cognitive side effects. However, research on their persistence, severity, and pattern is inconsistent. We aimed to quantify ECT-associated cognitive changes, specify their pattern, and determine progression.

METHODS

MEDLINE, EMBASE, PsycArticles, PsychINFO, PsychLIT, and reference lists were systematically searched through January 2009. We included all independent, within-subjects design studies of depressed patients receiving ECT where cognition was assessed using standardized tests. Main outcome was change in performance after ECT relative to pretreatment scores with respect to delay between finishing ECT and cognitive testing. We explored potential moderators' influence, e.g., electrode placement, stimulus waveform.

RESULTS

Twenty-four cognitive variables (84 studies, 2981 patients) were meta-analyzed. No standardized retrograde amnesia tests were identified. Significant decreases in cognitive performance were observed 0 to 3 days after ECT in 72% of variables: effect sizes (ES) ranging from -1.10 (95% confidence interval [CI], -1.53 to -.67) to -.21 (95% CI, -.40 to .01). Four to 15 days post-ECT, all but one CI included zero or showed positive ES. No negative ES were observed after 15 days, with 57% of variables showing positive ES, ranging from .35 (95% CI, .07-.63) to .75 (95% CI, .43-1.08). Moderators did not influence cognitive outcomes after 3 days post-ECT.

CONCLUSIONS

Cognitive abnormalities associated with ECT are mainly limited to the first 3 days posttreatment. Pretreatment functioning levels are subsequently recovered. After 15 days, processing speed, working memory, anterograde memory, and some aspects of executive function improve beyond baseline levels.

Therapeutic armamentarium for treating depression

Depressive disorders are highly prevalent and are a leading cause of disability, morbidity, and mortality worldwide; however, they often remain undertreated or untreated. This article provides a broad overview of the many strategies for treating depression. More than 24 antidepressant medications and depression-focused psychotherapies are available as first-choice options for treating depression. When patients have not had a satisfactory treatment response, the 2 main strategies are switching to an alternative antidepressant therapy or adding a second antidepressant therapy. A large number of medication combinations have been reported in the literature, and some have been shown to be effective in controlled studies. Nonstandard alternatives to conventional antidepressant treatments include exercise, light therapy, sleep deprivation, and various complementary and alternative therapies. For more chronic and refractory forms of depression, various neuromodulation therapies are available or are being investigated. Because depressive disorders are common in primary care and other medical settings, medical practitioners should be aware of the therapeutic armamentarium available for treating depression.

Electroconvulsive therapy stimulus parameters: rethinking dosage

In this article, we review the parameters that define the electroconvulsive therapy (ECT) electrical stimulus and discuss their biophysical roles. We also present the summary metrics of charge and energy that are conventionally used to describe the dose of ECT and the rules commonly deployed to individualize the dose for each patient. We then highlight the limitations of these summary metrics and dosing rules in that they do not adequately capture the roles of the distinct stimulus parameters. Specifically, there is strong theoretical and empirical evidence that stimulus parameters (pulse amplitude, shape, and width, and train frequency, directionality, polarity, and duration) exert unique neurobiological effects that are important for understanding ECT outcomes. Consideration of the distinct stimulus parameters, in conjunction with electrode placement, is central to further optimization of ECT dosing paradigms to improve the risk-benefit ratio. Indeed, manipulation of specific parameters, such as reduction of pulse width and increase in number of pulses, has already resulted in dramatic reduction of adverse effects, while maintaining efficacy. Furthermore, the manipulation of other parameters, such as current amplitude, which are commonly held at fixed, high values, might be productively examined as additional means of targeting and individualizing the stimulus, potentially reducing adverse effects. We recommend that ECT dose be defined using all stimulus parameters rather than a summary metric. All stimulus parameters should be noted in treatment records and published reports. To enable research on optimization of dosing paradigms, we suggest that ECT devices provide capabilities to adjust and display all stimulus parameters.

Introducing magnetic seizure therapy: A novel therapy for treatment resistant depression

OBJECTIVE

Electroconvulsive therapy (ECT) remains the only established therapy for the large percentage of patients with depression who fail to respond to standard treatments. It is commonly used but has substantial problems including the occurrence of cognitive side effects that are often highly distressing for patients. One highly promising potential alternative is magnetic seizure therapy (MST). This review provides an overview of the cognitive side effects of ECT and the attempts to overcome these, the history and development of MST is then reviewed, and finally a case study of the first patient treated in Australia with MST is presented.

METHODS

OVID and MEDLINE databases were used to search for the relevant literature. Reviews, meta-analyses and what were considered seminal articles were selected from the ECT literature to provide an overview of this large body of research. All of the known MST published work to date was included in this review.

RESULTS

The first patient treated in Australia underwent MST for treatment-resistant depression in October 2009. Extensive pre- and post-psychopathology and neurocognitive assessments were conducted. The patient no longer met criteria for a major depressive episode following eight MST treatments and has remained in remission at evaluations to date. She did not experience any disorientation following treatments and her neurocognitive assessments revealed no apparent MST-related cognitive side effects.

CONCLUSIONS

Research to date and our current findings provide considerable impetus to continue to vigorously investigate the use of MST in treatment resistant depression.

Effect of anatomical variability on neural stimulation strength and focality in electroconvulsive therapy (ECT) and magnetic seizure therapy (MST)

We present a quantitative comparison of two metrics-neural stimulation strength and focality-in electrocon-vulsive therapy (ECT) and magnetic seizure therapy (MST) using finite-element method (FEM) simulation in a spherical head model. Five stimulation modalities were modeled, including bilateral ECT, unilateral ECT, focal electrically administered seizure therapy (FEAST), and MST with circular and double-cone coils, with stimulation parameters identical to those applied in clinical practice. We further examine the effect on the stimulation metrics of individual-, sex- and age-related variability in tissue layer thickness and conductivity. Neural stimulation by MST is shown to be more focal and superficial than ECT. This result suggests that it may be advantageous to reduce the current used in ECT. The stimulation strength in MST is also less sensitive to variations in head geometry and tissue conductivity than in ECT. Individualization of pulse amplitude in both ECT and MST could compensate for anatomical variability, which could lead to more consistent clinical outcomes.

Meta-analysis of initial seizure thresholds in electroconvulsive therapy

In electroconvulsive therapy (ECT), electrical dosage is determined using 'fixed-dose', 'age-based' dose, or empirical titration methods. Estimation of initial seizure threshold (IST) has been claimed to be imperative for suprathreshold dosing. This systematic review aimed to determine common levels of IST, to define cut-off values for high IST, and to summarize reported IST associated factors. Medline and PsycINFO were searched from 1966 to January 2008 and relevant references were cross-checked. Subject headings including ECT, seizure threshold, dosage, and dosing were used. All articles reporting on levels of IST and/or associated factors were included. Of 395 potentially relevant reports, 46 studies on 70 samples concerning 3,023 patients were selected. Nine samples (n = 306 patients) without available standard deviation and four samples (n = 275 patients) treated with mixed electrode placement were excluded. Meta-analysis was done on 30 unilaterally treated samples (n = 1,326 patients) and 27 bilaterally treated samples (n = 1,116 patients). In unilateral ECT, weighted mean of IST was 68.2 milliCoulombs (mC; 95% CI 63.2-73.3 mC), and in bilateral ECT 111.6 mC (95% CI 103.7-119.4 mC). Calculated cut-off values for high IST were 121 mC for unilateral ECT and 221 mC for bilateral ECT. According to the literature, male gender and use of bilateral electrode placement appeared to increase IST most prominently. In conclusion, calculated electrical doses for 'suprathreshold' right unilateral ECT and for 'moderate above threshold' bilateral ECT, using commonly reported IST levels, were in the same though narrower ranges as provided in 'fixed-dose' and 'half-age' based strategies, respectively.

Effective utilization and future directions for repetitive transcranial magnetic stimulation: a guide for psychiatric nurses

Repetitive transcranial magnetic stimulation (rTMS) and magnetic seizure therapy (MST) represent new and promising avenues for treating mild and severe treatment-resistant depression, respectively. A further understanding of these modalities and the contribution of psychiatric nurses in the emerging field of brain stimulation would be of great use to the nursing community. This article serves as a primer for those who are interested in participating in or referring patients for research or treatment with rTMS or MST. Of particular emphasis is the role of certified psychiatric nurses as clinical rater, patient liaison, and evidence-based practitioner:

Unaltered neuronal and glial counts in animal models of magnetic seizure therapy and electroconvulsive therapy

Anatomical evidence of brain damage from electroconvulsive therapy (ECT) is lacking; but there are no modern stereological studies in primates documenting its safety. Magnetic seizure therapy (MST) is under development as a less invasive form of convulsive therapy, and there is only one prior report on its anatomical effects. We discerned no histological lesions in the brains of higher mammals subjected to electroconvulsive shock (ECS) or MST, under conditions that model closely those used in humans. We sought to extend these findings by determining whether these interventions affected the number of neurons or glia in the frontal cortex or hippocampus. Twenty-four animals received 6 weeks of ECS, MST, or anesthesia alone, 4 days per week. After perfusion fixation, numbers of neurons and glia in frontal cortex and hippocampus were determined by unbiased stereological methods. We found no effect of either intervention on volumes or total number or numerical density of neurons or glia in hippocampus, frontal cortex, or subregions of these structures. Induction of seizures in a rigorous model of human ECT and MST therapy does not cause a change in the number of neurons or glia in potentially vulnerable regions of brain. This study, while limited to young, healthy, adult subjects, provides further evidence that ECT and MST, when appropriately applied, do not cause structural damage to the brain.

Differential heart rate response to magnetic seizure therapy (MST) relative to electroconvulsive therapy: a nonhuman primate model

Electroconvulsive therapy (ECT) is an effective treatment for severe depression; however, the induced therapeutic seizure acts on the autonomic nervous system and results in significant cardiac effects. This is an important consideration particularly in the elderly. Magnetic seizure therapy (MST) is in development as a less invasive alternative, but its effects on cardiac function have not been studied. We sought to model those effects in nonhuman primates to inform the development of safer neurostimulation interventions. Twenty four rhesus monkeys were randomly assigned to receive 6 weeks of daily treatment with electroconvulsive stimulation (ECS), magnetic seizure therapy (MST) or anesthesia-alone sham. Digitally acquired ECG and an automated R-wave and inter-R interval (IRI) sampling were used to measure intervention effects on heart rate (HR). Significant differences between experimental conditions were found in the HR as evidenced by changes in the immediate post-stimulus, ictal and postictal epochs. Immediate post-stimulus bradycardia was seen with ECS but not with MST. ECS induced significantly more tachycardia than MST or sham in both the ictal and postictal periods. MST resulted in a small, but statistically significant increase in HR during the postictal period relative to baseline. HR was found to increase by 25% and 8% in the ECS and MST conditions, respectively. MST resulted in significantly less marked sympathetic and parasympathetic response than did ECS. This differential physiological response is consistent with MST having a more superficial cortical site of action with less impact on deeper brain structures implicated in cardiac control relative to ECT. The clinical relevance of the topographical seizure spread of MST and its associated effects on the autonomic nervous system remain to be determined in human clinical trials.

Translational development strategy for magnetic seizure therapy

Electroconvulsive therapy (ECT) has unparalleled antidepressant efficacy, but its cognitive side effects may be persistent. Research suggests that the side effects may be at least partially dissociable from the therapeutic effects of ECT, suggesting that distinct cortical networks may underlie them and introducing a role for focal seizure induction as a means of minimizing side effects. In magnetic seizure therapy (MST), magnetic fields avoid tissue impedance and induce electrical currents confined to superficial cortex, facilitating focal seizure induction. The translational development strategy for MST has included: (1) device development, (2) feasibility in animals and initial human trials, (3) testing in nonhuman primates on safety and mechanisms of action (with neuroanatomical, neurophysiological and cognitive endpoints), (4) safety testing in patients, (5) initial efficacy testing in patients, (6) dosage optimization, and (7) randomized comparison with ECT. These stages have been iterative, with results of early clinical testing prompting device enhancements that were, in turn, tested in nonhuman primates prior to human trials. Safety testing was aided by development of a nonhuman primate model of human ECT, and the validation of a cognitive battery for the monkey that is sensitive to the range of effects of ECT on human memory. Human testing has been facilitated by the development of an international consortium of centers addressing various aspects of technique and dose/response relationships. Challenges facing MST are common to other device-based therapies: characterizing dose/response relationships, optimizing efficacy, and developing efficient and reliable methods to induce lasting therapeutic change in the circuitry underlying depression.

Neurophysiological characterization of high-dose magnetic seizure therapy: comparisons with electroconvulsive shock and cognitive outcomes

Magnetic seizure therapy (MST) is under development as a means of improving cognitive outcomes with convulsive therapy through achieving better control over therapeutic seizure induction than is possible with conventional electroconvulsive therapy. In this investigation, we present the first neurophysiological characterization of high-dose MST (HD-MST, 6x seizure threshold) to see if a higher dose that is often used in human trials retains differential expression relative to electroconvulsive shock (ECS) and to explore the relationship between seizure expression and cognitive outcomes. To this end, rhesus monkeys received 4 weeks of daily treatment with ECS, HD-MST, and anesthesia-alone sham in counterbalanced order, with an interposed recovery period. Two channels of electroencephalogram were recorded during and immediately after the ictal period. Electroencephalogram power within delta, theta, alpha, and beta frequency bands was calculated. Electroconvulsive shock showed significantly more ictal power in all frequency bands than HD-MST (P < 0.01). Electroencephalogram power during the postictal period was significantly different among conditions only for the delta band. Higher ictal expression with ECS was associated with slowed completion time for an orientation task given immediately after the treatments. Our results support earlier findings demonstrating that MST- and ECS-induced seizures elicit differential patterns of ictal expression, consistent with the relatively more superficial stimulation achieved via magnetic induction in comparison with conventional electroconvulsive therapy. These results demonstrate that MST, even at high dose, results in seizures that differ neurophysiologically from ECS. It further suggests that some of the differences in ictal expression may relate to the improved cognitive outcomes seen with MST.

Focal electrically administered seizure therapy: a novel form of ECT illustrates the roles of current directionality, polarity, and electrode configuration in seizure induction

Electroconvulsive therapy (ECT) is a mainstay in the treatment of severe, medication-resistant depression. The antidepressant efficacy and cognitive side effects of ECT are influenced by the position of the electrodes on the head and by the degree to which the electrical stimulus exceeds the threshold for seizure induction. However, surprisingly little is known about the effects of other key electrical parameters such as current directionality, polarity, and electrode configuration. Understanding these relationships may inform the optimization of therapeutic interventions to improve their risk/benefit ratio. To elucidate these relationships, we evaluated a novel form of ECT (focal electrically administered seizure therapy, FEAST) that combines unidirectional stimulation, control of polarity, and an asymmetrical electrode configuration, and contrasted it with conventional ECT in a nonhuman primate model. Rhesus monkeys had their seizure thresholds determined on separate days with ECT conditions that crossed the factors of current directionality (unidirectional or bidirectional), electrode configuration (standard bilateral or FEAST (small anterior and large posterior electrode)), and polarity (assignment of anode and cathode in unidirectional stimulation). Ictal expression and post-ictal suppression were quantified through scalp EEG. Findings were replicated and extended in a second experiment with the same subjects. Seizures were induced in each of the 75 trials, including 42 FEAST procedures. Seizure thresholds were lower with unidirectional than with bidirectional stimulation (p<0.0001), and lower in FEAST than in bilateral ECS (p=0.0294). Ictal power was greatest in posterior-anode unidirectional FEAST, and post-ictal suppression was strongest in anterior-anode FEAST (p=0.0008 and p=0.0024, respectively). EEG power was higher in the stimulated hemisphere in posterior-anode FEAST (p=0.0246), consistent with the anode being the site of strongest activation. These findings suggest that current directionality, polarity, and electrode configuration influence the efficiency of seizure induction with ECT. Unidirectional stimulation and novel electrode configurations such as FEAST are two approaches to lowering seizure threshold. Furthermore, the impact of FEAST on ictal and post-ictal expression appeared to be polarity dependent. Future studies may examine whether these differences in seizure threshold and expression have clinical significance for patients receiving ECT.

Emerging targets for antidepressant therapies

Despite adequate antidepressant monotherapy, the majority of depressed patients do not achieve remission. Even optimal and aggressive therapy leads to a substantial number of patients who show minimal and often only transient improvement. In order to address this substantial problem of treatment-resistant depression, a number of novel targets for antidepressant therapy have emerged as a consequence of major advances in the neurobiology of depression. Three major approaches to uncover novel therapeutic interventions are: first, optimizing the modulation of monoaminergic neurotransmission; second, developing medications that act upon neurotransmitter systems other than monoaminergic circuits; and third, using focal brain stimulation to directly modulate neuronal activity. We review the most recent data on novel therapeutic compounds and their antidepressant potential. These include triple monoamine reuptake inhibitors, atypical antipsychotic augmentation, and dopamine receptor agonists. Compounds affecting extra-monoamine neurotransmitter systems include CRF(1) receptor antagonists, glucocorticoid receptor antagonists, substance P receptor antagonists, NMDA receptor antagonists, nemifitide, omega-3 fatty acids, and melatonin receptor agonists. Focal brain stimulation therapies include vagus nerve stimulation (VNS), transcranial magnetic stimulation (TMS), magnetic seizure therapy (MST), transcranial direct current stimulation (tDCS), and deep brain stimulation (DBS).

Magnetic seizure therapy of treatment-resistant depression in a patient with bipolar disorder

Electroconvulsive therapy (ECT) is a highly efficacious treatment for severe depression. However, a disadvantage of ECT is the risk of cognitive side effects. Magnetic seizure therapy (MST) is a novel treatment modality, by which therapeutic seizures are induced using rapidly alternating strong magnetic fields. In this case study, we report on successful MST treatment of an episode of otherwise treatment-resistant depression in a patient with bipolar I disorder. Compared with published ECT results, MST seizures in this case report were of shorter duration, lower ictal electroencephalogram amplitude, and less pronounced postictal suppression. Furthermore, the patient did not experience subjective side effects and particularly recovered time to full orientation more quickly with MST than what has been previously described for ECT. Taken together, these results suggest that MST, compared with ECT, might have antidepressant effects and may have fewer clinical side effects.

Treatment strategies to improve and sustain remission in major depressive disorder

Major depressive disorder (MDD) is an often chronic, recurrent illness affecting large numbers of the general population. In recent years, the goal of treatment for MDD has moved from mere symptomatic response to that of full remission (i.e., minimal/no residual symptoms). The recent Sequenced Treatment Alternatives to Relieve Depression (STAR*D) trial showed that even with systematic measurement-based treatment, approximately one third of patients reach full remission after one treatment trial, with only two thirds reaching remission after four treatment trials. Treatment-resistant depression (TRD) is therefore a common problem in the treatment of MDD, with 60% to 70% of all patients meeting the criteria for TRD. Given the huge burden of major depressive illness, the low rate of full recovery remains suboptimal. The following article reports on some current treatment strategies available to improve rates of, and to sustain, remission in MDD.

Neurostimulatory therapeutics in management of treatment-resistant depression with focus on deep brain stimulation

Treatment-resistant depression continues to pose a major medical challenge, as up to one-third of patients with major depressive disorder fail to have an adequate response to standard pharmacotherapies. An improved understanding of the complex circuitry underlying depressive disorders has fostered an explosion in the development of new, nonpharmacological approaches. Each of these treatments seeks to restore normal brain activity via electrical or magnetic stimulation. In this article, the authors discuss the ongoing evolution of neurostimulatory treatments for treatment-resistant depression, reviewing the methods, efficacy, and current research on electroconvulsive therapy, repetitive transcranial magnetic stimulation, magnetic seizure therapy, focal electrically administered stimulated seizure therapy, transcranial direct current stimulation, chronic epidural cortical stimulation, and vagus nerve stimulation. Special attention is given to deep brain stimulation, the most focally targeted approach. The history, purported mechanisms of action, and current research are outlined in detail. Although deep brain stimulation is the most invasive of the neurostimulatory treatments developed to date, it may hold significant promise in alleviating symptoms and improving the quality of life for patients with the most severe and disabling mood disorders.

Novel targets for antidepressant therapies

Most depressed patients fail to achieve remission despite adequate antidepressant monotherapy, and a substantial minority show minimal improvement despite optimal and aggressive therapy. However, major advances have taken place in elucidating the neurobiology of depression, and several novel targets for antidepressant therapy have emerged. Three primary approaches are currently being taken: 1) optimizing the pharmacologic modulation of monoaminergic neurotransmission, 2) developing medications that target neurotransmitter systems other than the monoamines, and 3) directly modulating neuronal activity via focal brain stimulation. We review novel therapeutic targets for developing improved antidepressant therapies, including triple monoamine reuptake inhibitors, atypical antipsychotic augmentation, dopamine receptor agonists, corticotropin-releasing factor-1 receptor antagonists, glucocorticoid receptor antagonists, substance P receptor antagonists, N-methyl-D-aspartate receptor antagonists, nemifitide, omega-3 fatty acids, and melatonin receptor agonists. Developments in therapeutic focal brain stimulation include vagus nerve stimulation, transcranial magnetic stimulation, magnetic seizure therapy, transcranial direct current stimulation, and deep brain stimulation.

Quick recovery of orientation after magnetic seizure therapy for major depressive disorder

BACKGROUND

Magnetic seizure therapy, in which seizures are elicited with a high-frequency magnetic field, is under development as a new treatment for major depressive disorder. Its use may be justified if it produces the antidepressant effects of electroconvulsive therapy (ECT), coupled with limited cognitive side-effects.

AIMS

To evaluate the usefulness of a new 100 Hz magnetic seizure therapy device.

METHOD

We induced seizures with 100 Hz magnetic transcranial stimulation in 11 patients with major depressive disorder during one session of a regular course of ECT. Recovery times after seizures induced by magnetic seizure therapy and ECT were compared.

RESULTS

Seizures could be elicited in 10 of the 11 patients. Stimulation over the vertex produced tonic-clonic activity on 9 out of 11 occasions. Stimulation over the prefrontal midpoint elicited seizures on 3 out of 7 occasions. The mean duration of magnetically induced seizures was 31.3 s, ranging from 10 to 86 s. All patients had an exceptionally quick recovery of orientation: mean of 7 min 12 s (s.d.=2 min 7 s, range 4 min 20 s to 9 min 41 s). The recovery times were on average 15 min 35 s shorter with magnetic seizure therapy than with ECT in the same patients (paired-samples t-test: P<0.0001). Patients reported feeling less confused after magnetic seizure therapy. Side-effects were confined to myoclonic movements, associated with the use of etomidate.

CONCLUSIONS

The new 100 Hz magnetic stimulator elicits seizures in the majority of patients when administered over the vertex. Magnetic seizure therapy was associated with shorter recovery times and less confusion following treatment. Subsequent work will be required to assess the safety and effectiveness of magnetic seizure therapy in the treatment of depression.

Differential neurophysiological effects of magnetic seizure therapy (MST) and electroconvulsive shock (ECS) in non-human primates

Magnetic seizure therapy (MST) is under development as a means of reducing the side effects of electroconvulsive therapy (ECT) through enhanced control over patterns of seizure induction and spread. We previously reported that chronic treatment with MST resulted in less impairment in cognitive function than electroconvulsive shock (ECS) in a non-human primate model of convulsive therapy. Here we present quantitative analyses of ictal expression and post-ictal suppression following ECS, MST, and anesthesia-alone sham in the same model to test whether differential neurophysiological characteristics of the seizures could be identified. Rhesus monkeys received 4 weeks of daily treatment with ECS, MST, and anesthesia-alone sham in a counterbalanced order separated by a recovery period. Both ECS and MST were given bilaterally at 2.5 x seizure threshold. Neurophysiological characteristics were derived from two scalp EEG electrode recording sites during and immediately following the ictal period, and were compared to sham treatment. EEG power within four frequencies (delta, theta, alpha and beta) was calculated. Our results support earlier findings from intracerebral electrode recordings demonstrating that MST- and ECS- induced seizures elicit differential patterns of EEG activation. Specifically, we found that ECS shows significantly more marked ictal expression, and more intense post-ictal suppression than MST in the theta, alpha, and beta frequency bands (Ps < .05). However, the ECS and MST were indistinguishable in the delta frequency band during both ictal and post-ictal periods. These results demonstrate that magnetic seizure induction can result in seizures that differ in some neurophysiological respects compared with ECS, but that these modalities share some aspects of seizure expression. The clinical significance of these similarities and differences awaits clinical correlation.

Electroconvulsive therapy and its different indications

In spite of recent developments in the pharmacotherapy of depressive disorders, the delay until clinical improvement can be achieved, and the considerable rate of nonresponse and nonremission, are major problems which remain unresolved. Electroconvulsive therapy (ECT) is a nonpharmacologic biological treatment which has been proven to be a highly effective treatment option, predominantly for depression, but also for schizophrenia and other indications. Though there is a lack of controlled investigations on long-term treatments, ECT can also be used for relapse prevention during maintenance therapies. The safety and tolerability of electroconvulsive treatment have been enhanced by the use of modified stimulation techniques and by progress in modern anesthesia. Thus, today a safe treatment can also be offered to patients with higher somatic risks. ECT still represents an important option, especially in the therapy of treatment-resistant psychiatric disorders after medication treatment failures. Earlier consideration of ECT may reduce the rate of chronic and difficult-to-treat psychiatric disorders.

Differential effects of high-dose magnetic seizure therapy and electroconvulsive shock on cognitive function

BACKGROUND

Magnetic seizure therapy (MST) is under investigation as an alternative form of convulsive therapy that induces more focal seizures and spares cortical regions involved in memory. With a newly expanded version of the Columbia University Primate Cognitive Profile, we compared the cognitive effects of high-dose MST delivered at 100 Hz (6 x seizure threshold) with electroconvulsive shock (ECS) delivered at 2.5 x seizure threshold.

METHODS

Daily high-dose MST, ECS, and sham (anesthesia-only) were administered for 4 weeks each in a within-subject crossover design. Rhesus macaques (n = 3) were trained on five cognitive tasks assessing automatic memory, anterograde learning and memory, combined anterograde and retrograde simultaneous chaining, and spatial and serial working memory. Acutely after each intervention, monkeys were tested on the cognitive battery twice daily, separated by a 3-hour retention interval.

RESULTS

Subjects were slower to complete criterion tasks (p values < .0001) after ECS, compared with sham and high-dose MST. Moreover, time to task-completion after high-dose MST did not differ from sham. Of six measures of accuracy, treatment effects were found in four; in all of these, ECS but not MST fared worse than sham. On all accuracy and time to completion measurements, subjects performed as well after high-dose MST as subjects from a previous study on moderate-dose MST.

CONCLUSIONS

These findings provide evidence that high-dose MST results in benign acute cognitive side-effect profile relative to ECS and are in line with our previous studies.

Brain stimulation techniques for the treatment of depression and other psychiatric disorders

OBJECTIVE

The aim of this paper was to review the development of repetitive transcranial magnetic stimulation (rTMS), magnetic seizure therapy (MST), vagal nerve stimulation (VNS), deep brain stimulation (DBS) and other recent brain stimulation techniques for their potential use in the treatment of a range of psychiatric disorders.

CONCLUSIONS

A considerable number of studies have been conducted to investigate the efficacy of rTMS. Although there are considerable problems with this research base, globally the studies suggest that rTMS has antidepressant efficacy. However, more research is required to define the most effective way of applying this technique. There is a much smaller research base supporting the use of VNS and to date the research suggests that only a minority of patients benefit from this procedure. Considerably more research is required in the use of the other techniques which at this stage have been tested only to a very small degree. It is likely that one, and possibly a number, of the new brain stimulation techniques will become available clinically in the psychiatric armamentarium in the coming years. However, considerable research is still required to establish efficacy and define the appropriate place in clinical practice for these treatment approaches.