Vagus nerve stimulation in depression

Youtube as a source of information vagal nerve stimulation: A quality analysis

PURPOSE

To evaluate the quality of available information on Youtube videos about VNS as a "source of health information" for patients with drug resistant epilepsy.

METHODS

Youtube videos were searched and screened using the terms "VNS for seizures," and "VNS surgery," "VNS epilepsy" in May 2023. The quality of the videos was evaluated the Quality Criteria for Consumer Health Information (DISCERN) and Global Quality Scale (GQS). The videos were analyzed in terms of content, accuracy, reliability, and quality.

RESULTS

A total of 104 videos were searched. After excluding duplicate or inappropriate videos, 51 videos were analyzed. Youtube videos about vagal nerve stimulation are mostly on general information, surgical procedures, patient experiences and magnet use. When video sources are examined according to the quality, according to GQS, 75 % of high quality videos were narrated by physicians, all intermediate quality videos were narrated by physicians, and low quality ones narrated by physicians were 47.4 % and 28.9 % by the patients. All of the videos narrated by the patients were of low quality. There was a significant and strong correlation between GQS and Discern score (r = 0.807, p < 0.001). Only GQS scores of videos with different content were found to be statistically significant (p < 0.05). Two pediatric neurologists independently reviewed the videos and classified the videos as useful or misleading according to the GQS, DISCERN scala. The overall κ value for interobserver consistency according to Global Quality Scale was 0.781 (p < 0.001). (95 % confidence interval), indicating a very good level of agreement.

CONCLUSION

Youtube videos may provide a worthful source for patients and parents seeking to find more information about VNS However incorrect information could easily be disseminated by high number of views of videos with low quality. High skilled and experienced professionals should create videos on Youtube to ensure that patients and parents can access more useful, high-quality, and accurate information on VNS.

Activation of α7 nicotinic acetylcholine receptor retards the development of endometriosis

BACKGROUND

Women with endometriosis have been shown to have a reduced vagal tone as compared with controls and vagotomy promoted while vagus nerve stimulation (VNS) decelerated the progression of endometriosis in mice. Extensive research also has shown that the activation of the cholinergic anti-inflammatory pathway by VNS activates α7 nicotinic acetylcholine receptor (α7nAChR), potently reducing inflammation. Yet whether α7nAChR plays any role in endometriosis is unknown. We evaluated its expression in normal endometrium, ovarian and deep endometriotic lesions, and evaluated its role in the development of endometriosis.

METHODS

Immunohistochemistry analyses of α7nAChR in endometriotic lesions as well as control endometrium, and quantification of tissue fibrosis by Masson trichrome staining were performed. Mouse experiments were conducted to evaluate the impact of α7nAChR activation or suppression on lesional progression and possible therapeutic effect. Finally, in vitro experiments were conducted to evaluate the effect of activation of α7nAChR on epithelial-mesenchymal transition (EMT), fibroblast-to-myofibroblast transdifferentiation (FMT), smooth muscle metaplasia (SMM) and fibrogenesis in an endometriotic epithelial cell line and primary endometriotic stromal cells derived from ovarian endometrioma tissue samples.

RESULTS

Immunostaining of α7nAChR was significantly reduced in human endometriotic epithelial cells as compared with their counterpart in normal endometrium. Lesional α7nAChR staining levels correlated negatively with lesional fibrosis and the severity of dysmenorrhea. The α7nAChR agonist significantly impeded the development of endometriotic lesions in mouse models possibly through hindrance of EMT and FMT. It also demonstrated therapeutic effects in mice with induced deep endometriosis. Treatment of endometriotic epithelial and stromal cells with an α7nAChR agonist significantly abrogated platelet-induced EMT, FMT and SMM, and suppressed cellular contractility and collagen production.

CONCLUSIONS

α7nAChR is suppressed in endometriotic lesions, and its activation by pharmacological means can impede EMT, FMT, SMM, and fibrogenesis of endometriotic lesions. As such, α7nAChR can be rightfully viewed as a potential target for therapeutic invention.

TRIAL REGISTRATION

Not applicable.

Non-invasive Vagus Nerve Stimulation in Cerebral Stroke: Current Status and Future Perspectives

Stroke poses a serious threat to human health and burdens both society and the healthcare system. Standard rehabilitative therapies may not be effective in improving functions after stroke, so alternative strategies are needed. The FDA has approved vagus nerve stimulation (VNS) for the treatment of epilepsy, migraines, and depression. Recent studies have demonstrated that VNS can facilitate the benefits of rehabilitation interventions. VNS coupled with upper limb rehabilitation enhances the recovery of upper limb function in patients with chronic stroke. However, its invasive nature limits its clinical application. Researchers have developed a non-invasive method to stimulate the vagus nerve (non-invasive vagus nerve stimulation, nVNS). It has been suggested that nVNS coupled with rehabilitation could be a promising alternative for improving muscle function in chronic stroke patients. In this article, we review the current researches in preclinical and clinical studies as well as the potential applications of nVNS in stroke. We summarize the parameters, advantages, potential mechanisms, and adverse effects of current nVNS applications, as well as the future challenges and directions for nVNS in cerebral stroke treatment. These studies indicate that nVNS has promising efficacy in reducing stroke volume and attenuating neurological deficits in ischemic stroke models. While more basic and clinical research is required to fully understand its mechanisms of efficacy, especially Phase III trials with a large number of patients, these data suggest that nVNS can be applied easily not only as a possible secondary prophylactic treatment in chronic cerebral stroke, but also as a promising adjunctive treatment in acute cerebral stroke in the near future.

Anatomo-Physiologic Basis for Auricular Stimulation

Introduction: Stimulation of cranial nerves modulates central nervous system (CNS) activity via the extensive connections of their brainstem nuclei to higher-order structures. Clinical experience with vagus-nerve stimulation (VNS) demonstrates that it produces robust therapeutic effects, however, posing concerns related to its invasiveness and side-effects. Discussion: Trigeminal nerve stimulation (TNS) has been recently proposed as a valid alternative to VNS. The ear presents afferent vagus and trigeminal-nerve distribution; its innervation is the theoretical basis of different reflex therapies, including auriculotherapy. An increasing number of studies have shown that several therapeutic effects induced by invasive VNS and TNS, can be reproduced by noninvasive auricular-nerve stimulation. However, the sites and neurobiologic mechanisms by which VNS and TNS produce their therapeutic effects are not clear yet. Conclusions: Accumulating evidence suggests that VNS and TNS share multiple levels and mechanisms of action in the CNS.

Cholinergic Modulation of Type 2 Immune Responses

In recent years, the bidirectional relationship between the nervous and immune system has become increasingly clear, and its role in both homeostasis and inflammation has been well documented over the years. Since the introduction of the cholinergic anti-inflammatory pathway, there has been an increased interest in parasympathetic regulation of both innate and adaptive immune responses, including T helper 2 responses. Increasing evidence has been emerging suggesting a role for the parasympathetic nervous system in the pathophysiology of allergic diseases, including allergic rhinitis, asthma, food allergy, and atopic dermatitis. In this review, we will highlight the role of cholinergic modulation by both nicotinic and muscarinic receptors in several key aspects of the allergic inflammatory response, including barrier function, innate and adaptive immune responses, and effector cells responses. A better understanding of these cholinergic processes mediating key aspects of type 2 immune disorders might lead to novel therapeutic approaches to treat allergic diseases.

Brain stimulation treatments in bipolar disorder: A review of the current literature

OBJECTIVES

Brain stimulation techniques are non-pharmacologic strategies which offer additional therapeutic options for treatment-resistant depression (TRD). The purpose of this paper is to review the current literature regarding the use of brain stimulation in resistant bipolar disorder (BD), with particular reference to hypomanic/manic symptoms.

METHODS

Keywords pertaining to the brain simulation techniques used in the treatment of depression (either unipolar or bipolar) along with their role in regard to hypomanic/manic symptoms were used to conduct an electronic search of the literature. Pertinent findings were identified by the authors and reviewed.

RESULTS

Brain stimulation techniques represent a valid therapeutic option in TRD. They have been extensively studied in unipolar depression and, to a minor extent, in the depressive phase of BD, showing encouraging but often limited results. With exception of electroconvulsive therapy, the efficacy of brain stimulation in the treatment of manic symptoms of bipolar patients is still uncertain and needs to be fully evaluated.

CONCLUSIONS

Brain stimulation in BD is derived from its use in unipolar depression. However, there are many important differences between these two disorders and more studies with a systematic approach need to be conducted on larger samples of bipolar patients with treatment-resistant characteristics.

Vagus nerve stimulation: state of the art of stimulation and recording strategies to address autonomic function neuromodulation

OBJECTIVE

Neural signals along the vagus nerve (VN) drive many somatic and autonomic functions. The clinical interest of VN stimulation (VNS) is thus potentially huge and has already been demonstrated in epilepsy. However, side effects are often elicited, in addition to the targeted neuromodulation.

APPROACH

This review examines the state of the art of VNS applied to two emerging modulations of autonomic function: heart failure and obesity, especially morbid obesity.

MAIN RESULTS

We report that VNS may benefit from improved stimulation delivery using very advanced technologies. However, most of the results from fundamental animal studies still need to be demonstrated in humans.

Posttraumatic Stress Disorder: Does the Gut Microbiome Hold the Key?

Gut bacteria strongly influence our metabolic, endocrine, immune, and both peripheral and central nervous systems. Microbiota do this directly and indirectly through their components, shed and secreted, ranging from fermented and digested dietary and host products to functionally active neurotransmitters including serotonin, dopamine, and γ-aminobutyric acid. Depression has been associated with enhanced levels of proinflammatory biomarkers and abnormal responses to stress. Posttraumatic stress disorder (PTSD) appears to be marked in addition by low cortisol responses, and these factors seem to predict and predispose individuals to develop PTSD after a traumatic event. Dysregulation of the immune system and of the hypothalamic-pituitary-adrenal axis observed in PTSD may reflect prior trauma exposure, especially early in life. Early life, including the prenatal period, is a critical time in rodents, and may well be for humans, for the functional and structural development of the immune and nervous systems. These, in turn, are likely shaped and programmed by gut and possibly other bacteria. Recent experimental and clinical data converge on the hypothesis that imbalanced gut microbiota in early life may have long-lasting immune and other physiologic effects that make individuals more susceptible to develop PTSD after a traumatic event and contribute to the disorder. This suggests that it may be possible to target abnormalities in these systems by manipulation of certain gut bacterial communities directly through supplementation or indirectly by dietary and other novel approaches.

Resting state vagal tone in borderline personality disorder: A meta-analysis

Borderline personality disorder (BPD) is the most common personality disorder in clinical settings. It is characterized by negative affectivity, emotional liability, anxiety, depression, as well as disinhibition (i.e., impulsivity and risk taking), all of which have been linked to lower resting state vagal tone, which may be indexed by vagally-mediated heart rate variability (vmHRV). Here, we aimed to quantify the current evidence on alterations in resting state vmHRV in individuals with BPD, relative to healthy controls. A rigorous search of the literature, according to the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses", revealed 5 studies suitable for meta-analysis, reporting vmHRV in individuals with BPD (n=95), relative to healthy controls (n=105). Short-term measures of resting state vmHRV were extracted and subjected to meta-analysis using both random- and fixed effect models in RevMan. BPD displayed lower resting state vmHRV relative to healthy controls in random- (Hedges' g=-0.59, 95% CI [-1.11; -0.06], k=5) and fixed-effect meta-analysis (Hedges' g=-0.56, 95% CI [-0.86; -0.27], k=5). Control for potential publication bias did not change observed findings. Lowered resting state vagal tone may be an important trait characteristic underlying BPD. As prior studies have observed lowered vmHRV in a variety of psychiatric disorders, we propose that lowered vmHRV may reflect a common psychophysiological mechanism underlying difficulties in emotion regulation and impulsivity, in particular.

Non-pharmacological biological treatment approaches to difficult-to-treat depression

There has been substantial recent interest in novel brain stimulation treatments for difficult-to-treat depression. Electroconvulsive therapy (ECT) is a well established, effective treatment for severe depression. ECT's problematic side-effect profile and questions regarding optimal administration methods continue to be investigated. Magnetic seizure therapy, although very early in development, shows promise, with potentially similar efficacy to ECT but fewer side effects. Vagus nerve stimulation (VNS) and repetitive transcranial magnetic stimulation (rTMS) are clinically available in some countries. Limited research suggests VNS has potentially long-lasting antidepressant effects in a small group of patients. Considerable research supports the efficacy of rTMS. Both techniques require further study of optimal treatment parameters. Transcranial direct current stimulation may provide a low-cost antidepressant option if its efficacy is substantiated in larger samples. Deep brain stimulation is likely to remain reserved for patients with the most severe and difficult-to-treat depression, requiring further exploration of administration methods and its role in depression therapy. New and innovative forms of brain stimulation, including low-intensity ultrasound, low-field magnetic stimulation and epidural stimulation of the cortical surface, are in early stages of exploration and are yet to move into the clinical domain. Ongoing work is required to define which brain stimulation treatments are likely to be most useful, and in which patient groups. Clinical service development of brain stimulation treatments will likely be inconsistent and variable.

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.

Prosocial effects of oxytocin and clinical evidence for its therapeutic potential

There has been unprecedented interest in the prosocial effects of the neuropeptide oxytocin in humans over the last decade. A range of studies has demonstrated correlations between basal oxytocin levels and the strength of social and bonding behaviors both in healthy individuals and in those suffering from psychiatric disorders. Mounting evidence suggests associations between polymorphisms in the oxytocin receptor gene and prosocial behaviors and there may also be important epigenetic effects. Many studies have now reported a plethora of prosocial effects of intranasal application of oxytocin, including the domains of trust, generosity, socially reinforced learning, and emotional empathy. The main focus of this review will be to summarize human preclinical work and particularly the rapidly growing number of clinical studies which have identified important links between oxytocin and a wide range of psychiatric disorders, and have now started to directly assess its therapeutic potential.

The World Federation of Societies of Biological Psychiatry (WFSBP) Guidelines for the Biological Treatment of Bipolar Disorders: Update 2010 on the treatment of acute bipolar depression

OBJECTIVES

These guidelines are based on a first edition that was published in 2002, and have been edited and updated with the available scientific evidence until September 2009. Their purpose is to supply a systematic overview of all scientific evidence pertaining to the treatment of acute bipolar depression in adults.

METHODS

The data used for these guidelines have been extracted from a MEDLINE and EMBASE search, from the clinical trial database clinicaltrials.gov, from recent proceedings of key conferences, and from various national and international treatment guidelines. Their scientific rigor was categorised into six levels of evidence (A-F). As these guidelines are intended for clinical use, the scientific evidence was finally assigned different grades of recommendation to ensure practicability.

RESULTS

We identified 10 pharmacological monotherapies or combination treatments with at least limited positive evidence for efficacy in bipolar depression, several of them still experimental and backed up only by a single study. Only one medication was considered to be sufficiently studied to merit full positive evidence.

CONCLUSIONS

Although major advances have been made since the first edition of this guideline in 2002, there are many areas which still need more intense research to optimize treatment. The majority of treatment recommendations is still based on limited data and leaves considerable areas of uncertainty.

Chronic vagus nerve stimulation induces neuronal plasticity in the rat hippocampus

Vagus nerve stimulation (VNS) is used to treat pharmacotherapy-resistant epilepsy and depression. However, the mechanisms underlying the therapeutic efficacy of VNS remain unclear. We examined the effects of VNS on hippocampal neuronal plasticity and behaviour in rats. Cell proliferation in the hippocampus of rats subjected to acute (3 h) or chronic (1 month) VNS was examined by injection of bromodeoxyuridine (BrdU) and immunohistochemistry. Expression of doublecortin (DCX) and brain-derived neurotrophic factor (BDNF) was evaluated by immunofluorescence staining. The dendritic morphology of DCX+ neurons was measured by Sholl analysis. Our results show that acute VNS induced an increase in the number of BrdU+ cells in the dentate gyrus that was apparent 24 h and 3 wk after treatment. It also induced long-lasting increases in the amount of DCX immunoreactivity and in the number of DCX+ neurons. Neither the number of BrdU+ cells nor the amount of DCX immunoreactivity was increased 3 wk after the cessation of chronic VNS. Chronic VNS induced long-lasting increases in the amount of BDNF immunoreactivity and the number of BDNF+ cells as well as in the dendritic complexity of DCX+ neurons in the hippocampus. In contrast to chronic imipramine treatment, chronic VNS had no effect on the behaviour of rats in the forced swim or elevated plus-maze tests. Both chronic and acute VNS induced persistent changes in hippocampal neurons that may play a key role in the therapeutic efficacy of VNS. However, these changes were not associated with evident behavioural alterations characteristic of an antidepressant or anxiolytic action.

Reactivation of inflammatory bowel disease in a mouse model of depression

BACKGROUND & AIMS

Patients with inflammatory bowel disease (IBD) frequently also have depression, yet little is known of its role in IBD pathogenesis. We investigated whether the development of depression after the establishment of chronic inflammation reactivates an acute relapse of IBD and underlying pharmacologic mechanisms in mouse models.

METHODS

Colitis was induced by administration of dextran sulfate sodium (DSS) or dinitrobenzenesulfonic acid to C57BL/6 mice. Depression was induced by olfactory bulbectomy or chronic intracerebroventricular injection of reserpine. Colitis was reactivated by subsequent exposure to DSS or dinitrobenzenesulfonic acid. Some mice were given the antidepressant desmethylimipramine. Acute DSS-colitis was induced in mice lacking the alpha 7 subunit of the nicotinic acetylcholine receptor (alpha 7nAchR), and vagotomy was performed. Disease severity and colon tissue histology and inflammation were evaluated. Levels of C-reactive protein and proinflammatory cytokines were determined by enzyme-linked immunosorbent assay analysis of colon samples and macrophage culture.

RESULTS

Induction of depression reactivated inflammation in mice in which colitis had been established and become quiescent. The induction was associated with impaired cholinergic inhibition of proinflammatory cytokine secretion by macrophages and mediated by alpha 7nAchR on these cells; macrophages isolated from depressed mice showed increased proinflammatory cytokine secretion. Depression-induced reactivation of colitis was prevented by desmethylimipramine and accompanied by a normalization of proinflammatory cytokine secretion.

CONCLUSIONS

Depression reactivates dormant chronic colitis via the alpha 7nAchR. These findings encourage closer monitoring of behavior for signs of depression in IBD patients because treatment might prevent inflammatory conditions. Furthermore, alpha 7nAchR agonists might achieve this effect without the need for psychotropic medication.

Cervical spinal MRI in a patient with a vagus nerve stimulator (VNS)

Cranial MRI has been shown to be a safe procedure in patients with a vagus nerve stimulator (VNS), but body MRI may cause overheating of the stimulator lead. Here we report a case of a patient with an implanted vagus nerve stimulator who required a cervical spinal MRI due to a rapidly progressive paraparesis. The spinal MRI was performed in a 1.5T scanner without complications showing a nearly complete compression of the spinal cord.

Impaired parasympathetic function increases susceptibility to inflammatory bowel disease in a mouse model of depression

Clinical and experimental evidence indicates that intestinal inflammatory conditions can be exacerbated by behavioral conditions such as depression. The recent demonstration of a tonic counterinflammatory influence mediated by the vagus nerve in experimental colitis provides a potential link between behavior and gut inflammation. Here we show that experimental conditions that induced depressive-like behaviors in mice increased susceptibility to intestinal inflammation by interfering with the tonic vagal inhibition of proinflammatory macrophages and that tricyclic antidepressants restored vagal function and reduced intestinal inflammation. These results show that reserpine-induced monoamine depletion and maternal separation, 2 models for depression, produced a vulnerability to colitis by a mechanism involving parasympathetic transmission and the presence of gut macrophages. The tricyclic antidepressant desmethylimipramine protected against this vulnerability by a vagal-dependent mechanism. Together these results illustrate the critical role of the vagus in both the vulnerability to inflammation induced by depressive-like conditions and the protection afforded by tricyclic antidepressants and rationalize a clinical evaluation of both parasympathomimetics and tricyclic antidepressants in treatment of inflammatory bowel disease.

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.

The use of repetitive transcranial magnetic stimulation and vagal nerve stimulation in the treatment of depression

PURPOSE OF REVIEW

Patients with depressive disorders often fail to respond to standard antidepressant medications and have few available treatment alternatives. Repetitive transcranial magnetic stimulation and vagal nerve stimulation have been developed and investigated over the last 10 years as potential treatment options for this and other psychiatric conditions. The aim of this paper is to review recent therapeutic trials of these techniques.

RECENT FINDINGS

Recent studies appear to have confirmed that standard left-sided repetitive transcranial magnetic stimulation has antidepressant efficacy, but that the degree of clinical effect may be somewhat limited. Promising data are emerging suggesting that other approaches, including right unilateral repetitive transcranial magnetic stimulation and sequential bilateral stimulation, may have equal or potentially greater effects. The evidence for the effectiveness of vagal nerve stimulation remains restricted to the primary company-sponsored trials. Although limited, these data suggest that valuable treatment effects may develop over time.

SUMMARY

Further repetitive transcranial magnetic stimulation research should actively investigate novel stimulation approaches before high-frequency left-sided stimulation is accepted as the standard approach. Given the invasive nature of vagal nerve stimulation and potential side effects, further research is urgently required. This should include the development of predictors of clinical response and definition of stimulation parameters with enhanced efficacy.

Pain in chronic pancreatitis: a salutogenic mechanism or a maladaptive brain response?

Pain in chronic pancreatitis is frequently refractory to medical and even surgical treatment. This refractoriness leads us to believe that a pancreas-independent, brain-mediated mechanism must be responsible. If so, several scenarios are worth considering. First, chronic pain could be the consequence of undesirable neuroplastic changes, by which pathology becomes established and causes disability. Alternatively, pain may be linked to the salutogenic (from salutogenesis, the Latin word for health and well-being) central nervous system response (we defined 'salutogenic response' as the specific modulation of the immune system induced by brain activity changes) to promote healing of the injured viscera. If so, chronic pain could index the ongoing nervous system attempt to promote healing. In this review, we discuss (1) the mechanisms of pain in chronic pancreatitis; (2) potential brain-related salutogenic mechanisms, and (3) the potential relationship of these two factors to the disease status. Furthermore, we consider these aspects in light of a new approach to treat visceral pain: transcranial magnetic stimulation, a noninvasive method of brain stimulation.

The burden of severe depression: a review of diagnostic challenges and treatment alternatives

Among the factors making recognition of severe depression problematic for clinicians are the heterogeneous nature of the condition, lack of standardized definitions, and concomitant comorbidities that confound differential diagnosis of symptoms. The spectrum of severity in depressive disorders is extraordinarily broad, and severity assessment is comprised of several metrics including symptom intensity, diagnostic subtypes, suicidality risk, and hospitalization status. The overall diagnosis is achieved through consideration of symptom types and severities together with the degree of functional impairment as assessed by the psychiatric interview. It is likely that no single fundamental neurobiological defect underlies severe depression. The chronicity and heterogeneity of this disorder lead to frequent clinic visits and a longer course of treatment; therefore, successful approaches may require an arsenal of treatments with numerous mechanisms of action. The categories of drugs used to treat severe depression are detailed herein, as are several non-pharmacologic options including a number of experimental treatments. Pharmacotherapies include tricyclic antidepressants, selective serotonin reuptake inhibitors, atypical antidepressants such as serotonin-norepinephrine reuptake inhibitors and monoamine oxidase inhibitors, and combination and augmentation therapies. Drugs within each class are not equivalent, and efficacy may vary with symptom severity. Patient adherence makes tolerability another critical consideration in antidepressant choice. The role of non-pharmacological treatments such as electroconvulsive therapy, vagus nerve stimulation, transcranial magnetic stimulation, and deep brain stimulation remain active avenues of investigation. Improved knowledge and treatment approaches for severe depression are necessary to facilitate remission, the ideal treatment goal.

VNS and depression: current status and future directions

Vagus nerve stimulation (VNS) is an established anticonvulsant therapy in treatment-resistant patients with epilepsy. The known anatomical projections of the vagus nerve to many brain regions that have been implicated in mood disorders suggest that VNS may also have useful antidepressant effects. There has been growing interest in the potential application of VNS in the nonpharmacological management of treatment-resistant depression. Results from an open-label study, in which 59 subjects with treatment-resistant depression were treated for 10 weeks with VNS therapy, reported a 31% response rate. In a recent controlled double-blind trial of VNS and depression, short-term treatment for 10 weeks failed to demonstrate statistical improvement over sham treatment. Results from the long-term phase of this trial may be more significant, however published data are awaited.

Electroconvulsive therapy for schizophrenia

BACKGROUND

Electroconvulsive therapy (ECT) involves the induction of a seizure for therapeutic purposes by the administration of a variable frequency electrical stimulus shock via electrodes applied to the scalp. The effects of its use in people with schizophrenia are unclear.

OBJECTIVES

To determine whether electroconvulsive therapy (ECT) results in clinically meaningful benefit with regard to global improvement, hospitalisation, changes in mental state, behaviour and functioning for people with schizophrenia, and to determine whether variations in the practical administration of ECT influences outcome.

SEARCH STRATEGY

We undertook electronic searches of Biological Abstracts (1982-1996), EMBASE (1980-1996), MEDLINE (1966-2004), PsycLIT (1974-1996),SCISEARCH (1996) and the Cochrane Schizophrenia Group's Register (July 2004). We also inspected the references of all identified studies and contacted relevant authors.

SELECTION CRITERIA

We included all randomised controlled clinical trials that compared ECT with placebo, 'sham ECT', non-pharmacological interventions and antipsychotics and different schedules and methods of administration of ECT for people with schizophrenia, schizoaffective disorder or chronic mental disorder.

DATA COLLECTION AND ANALYSIS

Working independently, we selected and critically appraised studies, extracted data and analysed on an intention-to-treat basis. Where possible and appropriate we calculated risk ratios (RR) and their 95% confidence intervals (CI) with the number needed to treat (NNT). For continuous data Weighted Mean Differences (WMD) were calculated. We presented scale data for only those tools that had attained pre-specified levels of quality. We also undertook tests for heterogeneity and publication bias.

MAIN RESULTS

This review includes 26 trials with 50 reports. When ECT is compared with placebo or sham ECT, more people improved in the real ECT group (n=392, 10 RCTs, RR 0.76 random CI 0.59 to 0.98, NNT 6 CI 4 to 12) and though data were heterogeneous (chi-square 17.49 df=9 P=0.04), its impact on variability of data was not substantial (I-squared 48.5%). There was a suggestion that ECT resulted in less relapses in the short term than sham ECT (n=47, 2 RCTs, RR fixed 0.26 CI 0.03 to 2.2), and a greater likelihood of being discharged from hospital (n=98, 1 RCT, RR fixed 0.59, CI 0.34 to 1.01). There is no evidence that this early advantage for ECT is maintained over the medium to long term. People treated with ECT did not drop out of treatment earlier than those treated with sham ECT (n=495, 14 RCTs, RR fixed 0.71 CI 0.33 to 1.52, I-squared 0%). Very limited data indicated that visual memory might decline after ECT compared with sham ECT (n=24, 1 RCT, WMD -14.0 CI -23 to -5); the results of verbal memory tests were equivocal. When ECT is directly compared with antipsychotic drug treatments (total n=443, 10 RCTs) results favour the medication group (n=175, 3 RCTs, RR fixed 'not improved at the end of ECT course' 2.18 CI 1.31 to 3.63). Limited evidence suggests that ECT combined with antipsychotic drugs results in greater improvement in mental state (n= 40, 1 RCT, WMD, Brief Psychiatric Rating Scale -3.9 CI - 2.28 to -5.52) than with antipsychotic drugs alone. One small study suggested more memory impairment after a course of ECT combined with antipsychotics than with antipsychotics alone (n=20, MD serial numbers and picture recall -4.90 CI -0.78 to -9.02), though this proved transient. When continuation ECT was added to antipsychotic drugs, the combination was superior to the use of antipsychotics alone (n=30, WMD Global Assessment of Functioning 19.06 CI 9.65 to 28.47), or CECT alone (n=30, WMD -20.30 CI -11.48 to -29.12). Unilateral and bilateral ECT were equally effective in terms of global improvement (n=78, 2 RCTs, RR fixed 'not improved at end of course of ECT' 0.79 CI 0.45 to 1.39). One trial showed a significant advantage for 20 treatments over 12 treatments for numbers globally improved at the end of the ECT course (n=43, RR fixed 2.53 CI 1.13 to 5.66).

AUTHORS' CONCLUSIONS

The evidence in this review suggests that ECT, combined with treatment with antipsychotic drugs, may be considered an option for people with schizophrenia, particularly when rapid global improvement and reduction of symptoms is desired. This is also the case for those with schizophrenia who show limited response to medication alone. Even though this initial beneficial effect may not last beyond the short term, there is no clear evidence to refute its use for people with schizophrenia. The research base for the use of ECT in people with schizophrenia continues to expand, but even after more than five decades of clinical use, there remain many unanswered questions regarding its role in the management of people with schizophrenia.

Repetitive transcranial magnetic stimulation and electroconvulsive therapy: complementary or competitive therapeutic options in depression?

OBJECTIVE

To examine issues pertaining to the potential clinical roles of repetitive transcranial magnetic stimulation (rTMS) and the relationship of these to the use of electroconvulsive therapy (ECT).

METHODS

A review of studies was carried out comparing the use of rTMS and ECT, with consideration of issues relating to the populations in which rTMS may be applied.

RESULTS

There have been a number of randomized comparisons of rTMS and ECT. There are limitations with these studies, but in general they indicate that in non-psychotic patients rTMS appears to have a similar rate of response to ECT and certainly seems to have meaningful clinical effects. There are a number of clinical subpopulations in whom rTMS, but not ECT, is suitable, and assessment of the effectiveness of TMS in these populations is required.

CONCLUSIONS

Repetitive TMS and ECT are likely to prove to be complementary clinical tools and the introduction of clinical programmes with rTMS will enhance patient options rather than replace the use of ECT.

Complex partial seizures and depression

A long-recognized association exists between epilepsy and affective disturbance, especially depression. People with complex partial seizures that result from temporal lobe seizure foci are highly vulnerable to psychiatric disorders. Accurate diagnosis of such disorders is an important key to treatment. Interictal depression or dysphoria is the most clinically significant problem of this type. Pharmacotherapeutic treatments that have positive effects in other types of depressive illness are also effective for depression associated with epilepsy. Electroconvulsive therapy is helpful to some patients with depression that is refractory to drug treatment or psychotherapy. Surgical resection of seizure foci may lead to psychiatric improvement for some individuals, but can also have psychiatric complications.