Clinically meaningful efficacy and acceptability of low-frequency repetitive transcranial magnetic stimulation (rTMS) for treating primary major depression: a meta-analysis of randomized, double-blind and sham-controlled trials

Repetitive transcranial magnetic stimulation (rTMS) for depressive-like symptoms in rodent animal models

Repetitive transcranial magnetic stimulation (rTMS) emerged as a non-invasive brain stimulation technique in the treatment of psychiatric disorders. Both preclinical and clinical studies as well as systematic reviews provide a heterogeneous picture, particularly concerning the stimulation protocols used in rTMS. Here, we present a review of rTMS effects in rodent models of depressive-like symptoms with the aim to identify the most relevant factors that lead to an increased therapeutic success. The influence of different factors, such as the stimulation parameters (stimulus frequency and intensity, duration of stimulation, shape and positioning of the coil), symptom severity and individual characteristics (age, species and genetic background of the rodents), on the therapeutic success are discussed. Accumulating evidence indicates that rTMS ameliorates a multitude of depressive-like symptoms in rodent models, most effectively at high stimulation frequencies (≥5 Hz) especially in adult rodents with a pronounced pathological phenotype. The therapeutic success of rTMS might be increased in the future by considering these factors and using more standardized stimulation protocols.

An Investigation of Parameter-Dependent Cell-Type Specific Effects of Transcranial Focused Ultrasound Stimulation Using an Awake Head-Fixed Rodent Model

Transcranial focused ultrasound (tFUS) is a promising neuromodulation technique able to target shallow and deep brain structures with high precision. Previous studies have demonstrated that tFUS stimulation responses are both cell-type specific and controllable through altering stimulation parameters. Specifically, tFUS can elicit time-locked neural activity in regular spiking units (RSUs) that is sensitive to increases in pulse repetition frequency (PRF), while time-locked responses are not seen in fast spiking units (FSUs). These findings suggest a unique capability of tFUS to alter circuit network dynamics with cell-type specificity; however, these results could be biased by the use of anesthesia, which significantly modulates neural activities. In this study, we develop an awake head-fixed rat model specifically designed for tFUS study, and address a key question if tFUS still has cell-type specificity under awake conditions. Using this novel animal model, we examined a series of PRFs and burst duty cycles (DCs) to determine their effects on neuronal subpopulations without anesthesia. We conclude that cell-type specific time-locked and delayed responses to tFUS as well as PRF and DC sensitivity are present in the awake animal model and that despite some differences in response, isoflurane anesthesia is not a major confound in studying the cell-type specificity of ultrasound neuromodulation. We further determine that, in an awake, head-fixed setting, the preferred PRF and DC for inducing time-locked excitation with our pulsed tFUS paradigm are 1500 Hz and 60%, respectively.

Investigating the impact of adjunctive priming repetitive transcranial magnetic stimulation in late-life depression: a pilot single-blind randomized control study

BACKGROUND

Conventional treatment methods have limited effectiveness in addressing late-life depression (LLD) that does not respond well. While a new approach called priming repetitive transcranial magnetic stimulation (rTMS) has shown promise in treating depression in adults, its effectiveness in LLD has not been explored. This study aimed to investigate the impact of priming rTMS on LLD.

METHODS

This study investigated the effectiveness of priming rTMS in 31 patients with LLD who did not improve after an adequate trial of antidepressants. Patients were randomly assigned to receive either active priming rTMS or sham priming rTMS. Active priming rTMS was delivered over the right dorsolateral prefrontal cortex for 10 sessions, lasting 31 minutes each, over a period of 2 weeks.

RESULTS

The group receiving active priming rTMS demonstrated greater improvements in scores on the Hamilton Rating Scale for Depression (p < 0.037; partial η2 0.141) and the Geriatric Depression Rating Scale (p < 0.045; partial η2 0.131) compared to the sham priming group, with a mild effect size. At the end of the second and fourth weeks, the priming rTMS group achieved a response rate of 50%, while the sham priming group had response rates of 26.7% and 6.7%, respectively. No adverse effects requiring intervention were observed.

CONCLUSION

Priming rTMS is well-tolerated for the treatment of LLD and not only reduces the severity of depression but also maintains the achieved response over time.

Neuroplasticity of the left dorsolateral prefrontal cortex in patients with treatment-resistant depression as indexed with paired associative stimulation: a TMS-EEG study

Major depressive disorder affects over 300 million people globally, with approximately 30% experiencing treatment-resistant depression (TRD). Given that impaired neuroplasticity underlies depression, the present study focused on neuroplasticity in the dorsolateral prefrontal cortex (DLPFC). Here, we aimed to investigate the differences in neuroplasticity between 60 individuals with TRD and 30 age- and sex-matched healthy controls (HCs). To induce neuroplasticity, participants underwent a paired associative stimulation (PAS) paradigm involving peripheral median nerve stimulation and transcranial magnetic stimulation (TMS) targeting the left DLPFC. Neuroplasticity was assessed by using measurements combining TMS with EEG before and after PAS. Both groups exhibited significant increases in the early component of TMS-evoked potentials (TEP) after PAS (P < 0.05, paired t-tests with the bootstrapping method). However, the HC group demonstrated a greater increase in TEPs than the TRD group (P = 0.045, paired t-tests). Additionally, event-related spectral perturbation analysis highlighted that the gamma power significantly increased after PAS in the HC group, whereas it was decreased in the TRD group (P < 0.05, paired t-tests with the bootstrapping method). This gamma power modulation revealed a significant group difference (P = 0.006, paired t-tests), indicating an inverse relationship for gamma power modulation. Our findings underscore the impaired neuroplasticity of the DLPFC in individuals with TRD.

Immune-inflammatory markers of response to repetitive transcranial magnetic stimulation in depression: A scoping review

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a safe, effective and non-invasive form of neuromodulatory therapy in patients with major depressive disorder (MDD). MDD is associated with increased peripheral and brain inflammation. The current paper aims to provide an overview of research examining the relationship between immune and inflammatory markers and response to rTMS in MDD.

METHODS

A scoping review method was adopted in keeping with the PRISMA-ScR guidelines. Twelve relevant studies were retrieved from the PubMed and Scopus databases and rated for study quality using a modified version of the BIOCROSS tool.

RESULTS

Response to rTMS in MDD was associated with basal and post-treatment levels of the inflammatory markers amyloid A, antithrombin III, oxidised phosphatidylcholine, and the microRNA miR-146a-5p. Inconsistent results were observed for the cytokines interleukin-1β, interleukin-2 and tumour necrosis factor-α. Increased baseline levels of interleukin-6 and C-reactive protein were linked to a poorer response to rTMS.

DISCUSSION

These results suggest that rTMS may have effects on immune-inflammatory pathways that are distinct from those of antidepressants and electroconvulsive therapy. Because of certain methodological limitations in the included studies, these results should be interpreted with caution.

An Evaluation of the Effectiveness of Repetitive Transcranial Magnetic Stimulation (rTMS) for the Management of Treatment-Resistant Depression with Somatic Attributes: A Hospital-Based Study in Oman

Depressive illnesses in non-Western societies are often masked by somatic attributes that are sometimes impervious to pharmacological agents. This study explores the effectiveness of repetitive transcranial magnetic stimulation (rTMS) for people experiencing treatment-resistant depression (TRD) accompanied by physical symptoms. Data were obtained from a prospective study conducted among patients with TRD and some somatic manifestations who underwent 20 sessions of rTMS intervention from January to June 2020. The Hamilton Rating Scale for Depression (HAMD) was used for clinical evaluation. Data were analysed using descriptive and inferential techniques (multiple logistic regression) in SPSS. Among the 49 participants (mean age: 42.5 ± 13.3), there was a significant reduction in posttreatment HAMD scores compared to baseline (t = 10.819, p < 0.0001, and 95% CI = 8.574-12.488), indicating a clinical response. Approximately 37% of the patients responded to treatment, with higher response rates among men and those who remained in urban areas, had a history of alcohol use, and were subjected to the standard 10 HZ protocol. After adjusting for all extraneous variables, the rTMS protocol emerged as the only significant predictor of response to the rTMS intervention. To our knowledge, this is the first study to examine the effectiveness of rTMS in the treatment of somatic depression.

The Role of Psychotherapy in the Management of Treatment-Resistant Depression

This article reviews the role of psychotherapy in management of treatment-resistant depression (TRD). Meta-analyses of randomized trials show that psychotherapy has a positive therapeutic benefit in TRD. There is less evidence that one type of psychotherapy approach is superior to another. However, more trials have examined cognitive-based therapies than other forms of psychotherapy. Also reviewed is the potential combination of psychotherapy modalities and medication/somatic therapies as an approach to TRD. There is significant interest in ways that psychotherapy modalities could be combined with medication/somatic therapies to harness a state of enhanced neural plasticity and improve longer-term outcomes in mood disorders.

Accelerated intermittent theta burst stimulation for major depressive disorder or bipolar depression: A systematic review and meta-analysis

We aimed to systematically evaluate the clinical efficacy and safety of accelerated intermittent theta burst stimulation (aiTBS) for patients with major depressive disorder (MDD) or bipolar depression (BD). A random-effects model was adopted to analyze the primary and secondary outcomes using the Review Manager, Version 5.3 software. This meta-analysis (MA) identified five double-blind randomized controlled trials (RCTs) comprising 239 MDD or BD patients with a major depressive episode. Active aiTBS overperformed sham stimulation in the study-defined response. This MA found preliminary evidence that active aiTBS resulted in a greater response in treating major depressive episodes in MDD or BD patients than sham stimulation.

An update on pharmacotherapy for recurrent depression in 2022

INTRODUCTION

Major depressive disorder remains a major challenge due to its biopsychosocial burden with increased morbidity and mortality. Despite successful treatment options for the acute episode, recurrence rates are high, on average four times in a life span.

AREAS COVERED

Both pharmacological as non-pharmacological evidence-based therapeutic options to prevent and treat recurrent depression are discussed.

EXPERT OPINION

Although some risk factors for recurrence are well known, better evidence is needed. Antidepressant medication should be continued after acute treatment at its full therapeutic dose for longer periods, at least 1 year. There are no clear differences between classes of antidepressant medication when treatment is focused on preventing relapse. Bupropion is the only antidepressant with a proven efficacy to prevent recurrence in seasonal affective disorder. Recent findings conclude maintenance subanesthetic ketamine and esketamine treatment can be effective in sustaining antidepressant effect following remission. Furthermore, the pharmacological approach must be integrated with lifestyle interventions, especially aerobic exercise. Finally, combining pharma- and psychotherapy seems to improve outcome. Network and complexity sciences will help to decrease the high recurrence rates of MDD by developing more integrative and personalized approaches.

To have and to hold: An exploratory qualitative study exploring why research participants with treatment-resistant depression undergoing transcranial magnetic stimulation treatment requested copies of their research brain MRI scans

PURPOSE

There has been little research providing an in-depth exploration of the reasons behind research participants, particularly in mental health settings, requesting copies of their research data, such as magnetic resonance imaging (MRI) scans. BRIGhTMIND is a large double blind randomised controlled trial using functional and structural magnetic resonance imaging to create personalised targets for transcranial magnetic stimulation delivery, and a number of trial participants requested copies of these scans.

METHODS

Seven participants involved in the BRIGhTMIND trial completed semi-structured interviews exploring their reasons behind their request for copies of their MRI scans. The qualitative data was co-analysed between researchers and patient and public involvement and engagement representatives using inductive thematic analysis.

RESULTS

The interviews produced consistent themes concerning curiosity to visualise their MRI scans, and the hope that their participation would result in a better understanding of the nature and future treatment of depression. Concerns around the rights to access their own personal health data emerged as a clear theme as did their own ability to interpret any radiological information.

DISCUSSION

This study provides insight into the reasons why research participants with depression would like to retain copies of their MRI scans and the perceived role that such techniques may have for improving research and neuromodulation treatments in depression. Such first-hand experiential accounts emphasises the importance of listening to participants perspectives and lived experience, in order to improve research and health outcomes. Future research could aim to provide greater verbal and written information for participants, including details about the accessibility to their MRI scans, the difference between research and clinical MRI scans, and educational materials to help with the interpretation of MRI images.

Personalized Repetitive Transcranial Magnetic Stimulation for Depression

Personalized treatments are gaining momentum across all fields of medicine. Precision medicine can be applied to neuromodulatory techniques, in which focused brain stimulation treatments such as repetitive transcranial magnetic stimulation (rTMS) modulate brain circuits and alleviate clinical symptoms. rTMS is well tolerated and clinically effective for treatment-resistant depression and other neuropsychiatric disorders. Despite its wide stimulation parameter space (location, angle, pattern, frequency, and intensity can be adjusted), rTMS is currently applied in a one-size-fits-all manner, potentially contributing to its suboptimal clinical response (∼50%). In this review, we examine components of rTMS that can be optimized to account for interindividual variability in neural function and anatomy. We discuss current treatment options for treatment-resistant depression, the neural mechanisms thought to underlie treatment, targeting strategies, stimulation parameter selection, and adaptive closed-loop treatment. We conclude that a better understanding of the wide and modifiable parameter space of rTMS will greatly improve the clinical outcome.

An effective brain connectivity technique to predict repetitive transcranial magnetic stimulation outcome for major depressive disorder patients using EEG signals

One of the most effective treatments for drug-resistant Major depressive disorder (MDD) patients is repetitive transcranial magnetic stimulation (rTMS). To improve treatment efficacy and reduce health care costs, it is necessary to predict the treatment response. In this study, we intend to predict the rTMS treatment response in MDD patients from electroencephalogram (EEG) signals before starting the treatment using machine learning approaches. Effective brain connectivity of 19-channel EEG data of MDD patients was calculated by the direct directed transfer function (dDTF) method. Then, using three feature selection methods, the best features were selected and patients were classified as responders or non-responders to rTMS treatment by using the support vector machine (SVM). Results on the 34 MDD patients indicated that the Fp2 region in the delta and theta frequency bands has a significant difference between the two groups and can be used as a significant brain biomarker to assess the rTMS treatment response. Also, the highest accuracy (89.6%) using the SVM classifier for the best features of the dDTF method based on the area under the receiver operating characteristic curve (AUC-ROC) criteria was obtained by combining the delta and theta frequency bands. Consequently, the proposed method can accurately detect the rTMS treatment response in MDD patients before starting treatment on the EEG signal to avoid financial and time costs to patients and medical centers.

Efficacy and safety of transcranial magnetic stimulation for treating major depressive disorder: An umbrella review and re-analysis of published meta-analyses of randomised controlled trials

OBJECTIVES

We re-analysed data from published meta-analyses testing the effects of Transcranial Magnetic Stimulation (TMS) on Major Depressive Disorder (MDD) in adults. We applied up-to-date meta-analytic techniques for handling heterogeneity including the random-effects Hartung-Knapp-Sidik-Jonkman method and estimated 95% prediction intervals. Heterogeneity practices in published meta-analyses were assessed as a secondary aim.

STUDY DESIGN AND SETTING

We performed systematic searches of systematic reviews with meta-analyses that included randomised controlled trials assessing the efficacy, tolerability, and side effects of TMS on MDD. We performed risk of bias assessment using A MeaSurement Tool to Assess Reviews (AMSTAR) 2 and re-analysed meta-analyses involving 10 or more primary studies.

RESULTS

We included 29 systematic reviews and re-analysed 15 meta-analyses. Authors of all meta-analyses interpreted findings to suggest TMS is safe and effective for MDD. Our re-analysis showed that in 14 out of 15 meta-analyses, the 95% prediction intervals included the null and captured values in the opposite effect direction. We also detected presence of small-study effects in some meta-analyses and 24 out of 25 systematic reviews received an AMSTAR 2 rating classed as critically low.

CONCLUSION

Authors of all included meta-analyses interpreted findings to suggest TMS is safe and effective for MDD despite lack of comprehensive investigation of heterogeneity. Our re-analysis revealed the direction and magnitude of treatment effects vary widely across different settings. We also found high risk of bias in the majority of included systematic reviews and presence of small-study effects in some meta-analyses. Because of these reasons, we argue TMS for MDD may not be as effective and potentially less tolerated in some populations than current evidence suggests.

Efficacy of High-Frequency Repetitive Transcranial Magnetic Stimulation at 10 Hz in Fibromyalgia: A Systematic Review and Meta-analysis

OBJECTIVE

The purpose of this review was to systematically assess the effectiveness of 10-Hz repetitive transcranial magnetic stimulation (rTMS) in fibromyalgia.

DATA SOURCES

We searched PubMed, Cochrane Library, Embase, Web of Science, and Ovid databases as of November 6, 2021.

STUDY SELECTION

The inclusion criteria for this review were randomized controlled trials of 10-Hz rTMS for fibromyalgia, exploring the effects of 10-Hz rTMS on pain, depression, and quality of life in patients with fibromyalgia.

DATA EXTRACTION

Data extraction was performed independently by 2 evaluators according to predefined criteria, and the quality of the included literature was assessed using the Cochrane Bias Risk Assessment Tool. The measurement outcomes include visual analog scale, Hamilton Depression Rating Scale, and Fibromyalgia Impact Questionnaire, and so on.

DATA SYNTHESIS

A total of 488 articles were screened, and the final 7 selected high-quality articles with 217 patients met our inclusion criteria. Analysis of the results showed that high-frequency transcranial magnetic stimulation at 10 Hz was significantly associated with reduced pain compared with sham stimulation in controls (standardized mean difference [SMD]=-0.72; 95% confidence interval [CI], -1.12 to -0.33; P<.001; I²=46%) and was able to improve quality of life (SMD=-0.70; 95% CI, -1.00 to -0.40; P<.001; I²=15%) but not improve depression (SMD=-0.23; 95% CI, -0.50 to 0.05; P=.11; I²=33%). In addition, a subgroup analysis of pain conducted based on stimulation at the primary motor cortex and dorsolateral prefrontal cortex showed no significant difference (SMD=-0.72; 95% CI, -1.12 to -0.33; P=.10; I²=62%).

CONCLUSIONS

Overall, 10-Hz rTMS has a significant effect on analgesia and improved quality of life in patients with FMS but did not improve depression.

Bilateral theta-burst stimulation on emotional processing in major depressive disorder: A functional neuroimaging study from a randomized, double-blind, sham-controlled trial

AIM

Bilateral theta-burst stimulation (biTBS; intermittent TBS over the left dorsolateral prefrontal cortex [DLPFC] and continuous TBS over the right DLPFC) has demonstrated efficacy in improving symptoms in patients with major depressive disorder (MDD). However, the underlying brain mechanisms remain unknown. The authors aimed to investigate the antidepressant efficacy of biTBS monotherapy and its effects on the brain responses measured by functional magnetic resonance imaging (fMRI) during emotional processing in MDD.

METHODS

The authors conducted a double-blind, randomized, sham-controlled trial of patients with MDD who exhibited no responses to at least one adequate antidepressant treatment for the prevailing episode. Recruited patients were randomly assigned to 10 biTBS monotherapy or sham stimulation sessions. The fMRI scans during performing emotional recognition task were obtained at baseline and after 10 sessions of treatment. Depressive symptoms were assessed using the 21-item Hamilton Rating Scale for Depression at baseline and the weeks 4, 8, 12, 16, 20, and 24 week.

RESULTS

The biTBS group (n = 17) exhibited significant decreases in depression scores compared with the sham group (n = 11) at week 8 (70% vs 40%; P = 0.02), and the significant differences persisted during the 24-week follow-up periods. At week 4, when the treatment course was completed, patients in the biTBS group, but not in the sham group, exhibited increased brain activities over the left superior and middle frontal gyrus during negative emotional stimuli.

CONCLUSION

The authors' findings provide the first evidence regarding the underlying neural mechanisms of biTBS therapy to improve clinical symptoms in patients with MDD.

Cerebral perfusion is related to antidepressant effect and cognitive side effects of Electroconvulsive Therapy

BACKGROUND

The mechanisms underlying the antidepressant effect and cognitive side effects of Electroconvulsive Therapy (ECT) remain elusive. The measurement of cerebral perfusion provides an insight into brain physiology.

OBJECTIVE

We investigated ECT-related perfusion changes in depressed patients and tested whether these changes correlate with clinical effects.

METHODS

A sample of 22 in-patients was examined at three time points: 1) within two days before, 2) within one week after, and 3) six months after an ECT series. Cerebral perfusion was quantified using arterial spin labeling magnetic resonance imaging. The primary regions of interest were the bilateral dorsolateral prefrontal cortices (DL-PFC) and hippocampi. The depression severity was assessed by the six-item Hamilton Depression Rating Scale, and cognitive performance by the Screen for Cognitive Impairment in Psychiatry. A linear mixed model and partial correlation were used for statistical analyses.

RESULTS

Following an ECT series, perfusion decreased in the right (-6.0%, p = .01) and left DL-PFC (-5.6%, p = .001). Perfusion increased in the left hippocampus (4.8%, p = .03), while on the right side the increase was insignificant (2.3%, p = .23). A larger perfusion reduction in the right DL-PFC correlated with a better antidepressant effect, and a larger perfusion increase in the right hippocampus with worse cognitive impairment.

CONCLUSION

ECT-induced attenuation of prefrontal activity may be related to clinical improvement, whereas a hippocampal process triggered by the treatment is likely associated with cognitive side effects.

Effect of priming on adjunctive repetitive transcranial magnetic stimulation in treatment of late life depression: Protocol of a prospective randomized sham-controlled study

Objective

Priming stimulation, which involves high-frequency repetitive transcranial magnetic stimulation (rTMS) followed by low-frequency, has been shown to enhance neural response and is one of the novel paradigms found beneficial in adult patients with depression and has not been studied in late-life depression (LLD). This study aims to compare the effect of adjunctive priming vis-a-vis no priming rTMS over right dorso-lateral prefrontal cortex (DLPFC), on treatment of LLD.

Methods

This trial is registered in Clinical Trial Registry-India (CTRI) on www.ctri.nic.in. CTRI registration number: CTRI/2020/08/027230. Forty patients of LLD who are symptomatic after an adequate antidepressant trial will be randomized into 2 groups (active priming and sham priming rTMS); each receiving 10 sessions of rTMS over 2 weeks. Patients will remain blind to treatment allocation. Assessments will be done using Hamilton rating scale for depression, Geriatric Depression Scale, Hamilton rating scale for Anxiety, Somatic Symptom Severity Scale 8, Hindi Mental Status Examination, and Clinical Global Impression scale at baseline, week 1, 2, and 4. Side effect checklist will be applied after each session in both groups and at the end of 4 weeks.

Result

Data will be analyzed using statistical software Statistical Package for Social Sciences. Both the groups (active and sham groups) will be compared at the four given timepoints. Also, the baseline characteristics will be compared with the 3 follow-up points for any change.

Conclusion

The findings of the study will give an insight to the possible role of priming to augment the effect of low-frequency rTMS in LLD.

Low frequency repetitive transcranial magnetic stimulation to the right dorsolateral prefrontal cortex engages thalamus, striatum, and the default mode network

The positive treatment outcomes of low frequency (LF) repetitive transcranial magnetic stimulation (rTMS) when applied over the right dorsolateral prefrontal cortex (DLPFC) in treatment-refractory depression has been verified. However, the mechanism of action behind these results have not been well-explored. In this work we used simultaneous functional magnetic resonance imaging (fMRI) during TMS to explore the effect of LF rTMS on brain activity when applied to the right [RDLPFC1 (MNI: 50, 30, 36)] and left DLPFC sites [LDLPFC1 (MNI: -50, 30, 36), LDLPFC2 (MNI: -41, 16, 54)]. Seventeen healthy adult volunteers participated in this study. To identify brain areas affected by rTMS, an independent component analysis and a general linear model were used. Our results showed an important laterality effect when contrasting rTMS over the left and right sites. Specifically, LF rTMS increased brain activity at the striatum, thalamus, and areas of the default mode network when applied to the right, but not to the contralateral left DLPFC. In contrast, no site differences were observed when evaluating the effect of LF rTMS over the two left sites. These findings demonstrate that LF rTMS to the right DLPFC was able to stimulate the cortico-striato-thalamo-cortical pathway, which is dysregulated in patients with major depressive disorder; therefore, possibly providing some neurobiological justification for the successful outcomes found thus far for LF rTMS in the treatment of depression.

The Association Between Sample and Treatment Characteristics and the Efficacy of Repetitive Transcranial Magnetic Stimulation in Depression: A Meta-analysis and Meta-regression of Sham-controlled Trials

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a form of non-invasive neuromodulation that is increasingly used to treat major depressive disorder (MDD). However, treatment with rTMS could be optimized by identifying optimal treatment parameters or characteristics of patients that are most likely to benefit. This meta-analysis and meta-regression aims to identify sample and treatment characteristics that are associated with change in depressive symptom level, treatment response and remission.

METHODS

The databases PubMed, Embase, Web of Science and Cochrane library were searched for randomized controlled trials (RCTs) reporting on the therapeutic efficacy of high-frequent, low-frequent, or bilateral rTMS for MDD compared to sham. Study and sample characteristics as well as rTMS parameters and outcome variables were extracted. Effect sizes were calculated for change in depression score and risk ratios for response and remission.

RESULTS

Sixty-five RCTs with a total of 2982 subjects were included in this meta-analysis. Active rTMS resulted in a larger depressive symptom reduction than sham protocol (Hedges' g = -0.791 95% CI -0.977; -0.605). Risk ratios for response and remission were 2.378 (95% CI 1.882; 3.005) and 2.450 (95% CI 1.779; 3.375), respectively. We found no significant association between sample and treatment parameters and rTMS efficacy.

CONCLUSIONS

rTMS is an efficacious treatment for MDD. No associations between sample or treatment characteristics and efficacy were found, for which we caution that publication bias, heterogeneity and lack of consistency in the definition of remission might bias these latter null findings. Our results are clinically relevant and support the use of rTMS as a non-invasive and effective treatment option for depression.

Non-invasive neuromodulation of dorsolateral prefrontal cortex to reduce craving in alcohol use disorder: A meta-analysis

Introduction

While several pharmacological and behavioral treatments are available for alcohol use disorder (AUD), they may not be effective for all patients. The aim of this systematic review and meta-analysis was to evaluate the efficacy and safety of rTMS and tDCS for craving in AUD.

Methods

EMBASE, Cochrane Library, PsycINFO, and PubMed databases were searched for original, peer-reviewed research articles in the English language published between January 2000 and January 2022. Randomized controlled trials (RCTs) reporting changes in alcohol craving among patients with AUD were selected. Random-effects meta-analysis was employed to pool data.

Results

Changes in alcohol craving were extracted from 15 RCTs. Six studies assessed the efficacy of rTMS while nine studies examined tDCS. Results demonstrated that in comparison to sham stimulation, active rTMS to the DLPFC yields small but significant reductions in alcohol craving (standardized mean difference [SMD] = -0.27, p = .03). However, DLPFC stimulation via tDCS was not superior to sham stimulation in producing changes in alcohol craving (SMD = -0.08, p = .59).

Conclusions

Our meta-analysis suggests that rTMS may be superior to tDCS in reducing alcohol craving in patients with AUD. However, additional research is needed to identify optimal stimulation parameters for both non-invasive neuromodulatory techniques in AUD.

The evidence is in: Repetitive transcranial magnetic stimulation is an effective, safe and well-tolerated treatment for patients with major depressive disorder

Despite more than 25 years of research establishing the antidepressant efficacy of repetitive transcranial magnetic stimulation, there remains uncertainty about the depth and breadth of this evidence base, resulting in confusion as to where repetitive transcranial magnetic stimulation fits in the therapeutic armamentarium in the management of patients with mood disorders. The purpose of this article is to provide a concise description of the evidence base supporting the use of repetitive transcranial magnetic stimulation in the context of the stages of research that typically accompanies the development of evidence for a new therapy. The antidepressant efficacy for the use of repetitive transcranial magnetic stimulation in the treatment of depression has been established through a relatively traditional pathway beginning with small case series, progressing to single-site clinical trials and then to larger multisite randomised double-blind controlled trials. Antidepressant effects have been confirmed in numerous meta-analyses followed more recently by large network meta-analysis and umbrella reviews, with evidence that repetitive transcranial magnetic stimulation may have greater efficacy than alternatives for patients with treatment-resistant depression. Finally, repetitive transcranial magnetic stimulation has been shown to produce meaningful response and remission rates in real-world samples of greater than 5000 patients. The evidence for the antidepressant efficacy of repetitive transcranial magnetic stimulation therapy is overwhelming, and it should be considered a routine part of clinical care wherever available.

Brain stimulation and other biological non-pharmacological interventions in mental disorders: An umbrella review

BACKGROUND

The degree of efficacy, safety, quality, and certainty of meta-analytic evidence of biological non-pharmacological treatments in mental disorders is unclear.

METHODS

We conducted an umbrella review (PubMed/Cochrane Library/PsycINFO-04-Jul-2021, PROSPERO/CRD42020158827) for meta-analyses of randomized controlled trials (RCTs) on deep brain stimulation (DBS), transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), electro-convulsive therapy (ECT), and others. Co-primary outcomes were standardized mean differences (SMD) of disease-specific symptoms, and acceptability (for all-cause discontinuation). Evidence was assessed with AMSTAR/AMSTAR-Content/GRADE.

RESULTS

We selected 102 meta-analyses. Effective interventions compared to sham were in depressive disorders: ECT (SMD=0.91/GRADE=moderate), TMS (SMD=0.51/GRADE=moderate), tDCS (SMD=0.46/GRADE=low), DBS (SMD=0.42/GRADE=very low), light therapy (SMD=0.41/GRADE=low); schizophrenia: ECT (SMD=0.88/GRADE=moderate), tDCS (SMD=0.45/GRADE=very low), TMS (prefrontal theta-burst, SMD=0.58/GRADE=low; left-temporoparietal, SMD=0.42/GRADE=low); substance use disorder: TMS (high frequency-dorsolateral-prefrontal-deep (SMD=1.16/GRADE=moderate), high frequency-left dorsolateral-prefrontal (SMD=0.77/GRADE=very low); OCD: DBS (SMD=0.89/GRADE=moderate), TMS (SMD=0.64/GRADE=very low); PTSD: TMS (SMD=0.46/GRADE=moderate); generalized anxiety disorder: TMS (SMD=0.68/GRADE=low); ADHD: tDCS (SMD=0.23/GRADE=moderate); autism: tDCS (SMD=0.97/GRADE=very low). No significant differences for acceptability emerged. Median AMSTAR/AMSTAR-Content was 8/2 (suggesting high-quality meta-analyses/low-quality RCTs), GRADE low.

DISCUSSION

Despite limited certainty, biological non-pharmacological interventions are effective and safe for numerous mental conditions. Results inform future research, and guidelines.

FUNDING

None.

Effects of Noninvasive Brain Stimulation Combined With Antidepressants in Patients With Poststroke Depression: A Systematic Review and Meta-Analysis

Objective: To evaluated the efficacy and safety of noninvasive brain stimulation (NIBS) combined with antidepressants in patients with poststroke depression (PSD).

Methods: Seven databases were searched to identify randomized controlled trials of NIBS combined with antidepressants in the treatment of PSD based on the international classification of diseases (ICD-10) criteria and exclusion criteria. The retrieval time was from the database establishment to 31 October 2021. Two researchers independently screened the identified studies through the search strategy, extracted their characteristics, and evaluated the quality of the included literature. Cochrane Collaboration’s tool was used to assess risk of bias. RevMan 5.3 software was applied for meta-analysis.

Results: A total of 34 randomized controlled trials were included, involving 2,711 patients with PSD. Meta-analysis showed that the total effective rate was higher in the combined therapy than the antidepressant alone [odds ratio (OR): 4.33; 95% confidence interval (CI): 3.07 to 6.11; p < 0.00001]. The Hamilton depressive scale (HAMD) score was significantly lower in repeated transcranial magnetic stimulation (rTMS) (≤10 Hz) combined with antidepressant than in antidepressant alone [standard mean difference (SMD): −1.44; 95% CI: −1.86 to −1.03; p < 0.00001]. No significant difference was seen in rTMS (>10 Hz) combined with antidepressant versus antidepressant alone (SMD: −4.02; 95% CI: −10.43 to 2.39; p = 0.22). In addition, combination therapy more strongly improved the modified Barthel index (MBI) scale than antidepressants [mean difference (MD): 8.29; 95% CI: 5.23–11.35; p < 0.00001]. Adverse effects were not significantly different between two therapies (OR: 1.33; 95% CI: 0.87 to 2.04; p = 0.18).

Conclusion: Low-frequency rTMS (≤10 Hz) combined with antidepressants tends to be more effective than antidepressants alone in patients with PSD, and there are no significant adverse effects. In addition, combined therapy may enhance quality of life after stroke. Combination therapy with high-frequency rTMS (>10 Hz) showed no advantage in treating PSD. The transcranial electrical stimulation (TES) combined with antidepressants might be more effective than antidepressants alone, which are needed to confirm by more clinical trials since the.

Repetitive Transcranial Magnetic Stimulation-Associated Changes in Neocortical Metabolites in Major Depression: A Systematic Review

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We reviewed 12 studies that measured metabolites pre and post rTMS in MDD.

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Frontal lobe Glu, Gln, NAA, and GABA increased after rTMS.

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Increases in metabolites were often associated with MDD symptom improvement.

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We propose novel intracellular mechanisms by which metabolites are altered by rTMS.

Introduction

Repetitive Transcranial magnetic stimulation (rTMS) is an FDA approved treatment for major depressive disorder (MDD). However, neural mechanisms contributing to rTMS effects on depressive symptoms, cognition, and behavior are unclear. Proton magnetic resonance spectroscopy (MRS), a noninvasive neuroimaging technique measuring concentrations of biochemical compounds within the brain in vivo, may provide mechanistic insights.

Methods

This systematic review summarized published MRS findings from rTMS treatment trials to address potential neurometabolic mechanisms of its antidepressant action. Using PubMed, Google Scholar, Web of Science, and JSTOR, we identified twelve empirical studies that evaluated changes in MRS metabolites in a within-subjects, pre- vs. post-rTMS treatment design in patients with MDD.

Results

rTMS protocols ranged from four days to eight weeks duration, were applied at high frequency to the left dorsolateral prefrontal cortex (DLPFC) in most studies, and were conducted in patients aged 13-to-70. Most studies utilized MRS point resolved spectroscopy acquisitions at 3 Tesla in the bilateral anterior cingulate cortex and DLPFC. Symptom improvements were correlated with rTMS-related increases in the concentration of glutamatergic compounds (glutamate, Glu, and glutamine, Gln), GABA, and N-acetylated compounds (NAA), with some results trend-level.

Conclusions

This is the first in-depth systematic review of metabolic effects of rTMS in individuals with MDD. The extant literature suggests rTMS stimulation does not produce changes in neurometabolites independent of clinical response; increases in frontal lobe glutamatergic compounds, N-acetylated compounds and GABA following high frequency left DLPFC rTMS therapy were generally associated with clinical improvement. Glu, Gln, GABA, and NAA may mediate rTMS treatment effects on MDD symptomatology through intracellular mechanisms.

High-frequency repetitive transcranial magnetic stimulation mitigates depression-like behaviors in CUMS-induced rats via FGF2/FGFR1/p-ERK signaling pathway

High-frequency repetitive transcranial magnetic stimulation (rTMS) is a widely used and effective biological treatment for depression. Although previous studies have shown that astrocyte function may be modified by rTMS, the specific neurobiological mechanisms underlying its antidepressant action are not clear. Substantial evidence has accumulated indicating that neurotrophin dysfunction and neuronal apoptosis play a role in the development of depression. To evaluate this hypothesis, we applied a chronical unpredictable mild stress (CUMS) protocol to induce depression-like behaviors in rats, followed by the delivery of 10-Hz rTMS for 3 weeks. Behavioral outcome measures consisted of a sucrose preference test, forced swimming test, and open field test. Histological analysis focused on apoptosis, expression of GFAP and FGF2, and FGF2 pathway-related proteins. The results showed that after rTMS treatment, the rats' sucrose preference increased, open field performance improved while the immobility time of forced swimming decreased. The behavioral changes seen in rTMS treated rats were accompanied by marked reductions in the number of TUNEL-positive neural cells and the level of expression of BAX and by an increase in Bcl2. Furthermore, the expression of GFAP and FGF2 was increased, along with activation of FGF2 downstream pathway. These results suggest that rTMS treatment can improve depression-like behavior, attenuate neural apoptosis, and reverse reduction of astrocytes in a rat model of depression. We hypothesize that the therapeutic action of rTMS in CUMS-induced rats is linked to the activation of the FGF2/FGFR1/p-ERK signaling pathway.

Bilateral sequential theta burst stimulation in depressed veterans with service related posttraumatic stress disorder: a feasibility study

BACKGROUND

Depression comorbid with posttraumatic stress disorder (PTSD) can be disabling and treatment resistant. Preliminary evidence suggests that repetitive transcranial magnetic stimulation (rTMS), may have a role in helping these patients. There are only few published studies using different rTMS paradigms including bilateral intermittent theta burst (iTBS) and low frequency rTMS.

METHODS

In this small cohort observation study, we examined the efficacy of bilateral sequential theta-burst stimulation (bsTBS) in 8 treatment resistant depression (TRD) military veterans with PTSD comorbidity stemming from military service experience.

RESULTS

bsTBS was generally well tolerated and resulted in 25% and 38% remission and response rates on Depression scores respectively; 25% remission and response rate on PTSD scores.

DISCUSSION

This study demonstrates preliminary feasibility and safety of bsTBS in TRD with comorbid military service related PTSD. We concluded that this paradigm might hold promise as a therapeutic tool to help patients with TRD co-morbid with military service related PTSD. Further adequately powered studies to compare rTMS treatment paradigms in this patient group are warranted.

Bilateral repetitive transcranial magnetic stimulation ameliorated sleep disorder and hypothalamic-pituitary-adrenal axis dysfunction in subjects with major depression

OBJECTIVE

In this study, we sought to explore the effectiveness of bilateral repetitive transcranial magnetic stimulation (rTMS) over the dorsolateral prefrontal cortex (DLPFC) on depressive symptoms and dysfunction of hypothalamic-pituitary-adrenal (HPA) axis in patients with major depressive disorder (MDD).

MATERIALS AND METHODS

One hundred and thirty-six adults with MDD were administrated drugs combined with 3 weeks of active rTMS (n = 68) or sham (n = 68) treatment. The 17-item Hamilton Depression Rating Scale for Depression (HAMD-17) was to elevate depression severity at baseline and weeks 4. To test the influence of rTMS on the HPA axis, plasma adrenocorticotropic hormone (ACTH) and serum cortisol (COR) were detected in pre- and post-treatment.

RESULTS

No statistical significance was found for the baseline of sociodemographic, characteristics of depression, and psychopharmaceutical dosages between sham and rTMS groups (p > 0.05). There was a significant difference in the HAMD-17 total score between the two groups at end of 4 weeks after treatment (p < 0.05). Compared to the sham group, the rTMS group demonstrated a more significant score reduction of HAMD-17 and sleep disorder factor (HAMD-SLD) including sleep onset latency, middle awakening, and early awakening items at end of 4-week after treatment (p < 0.05). Furthermore, total score reduction of HAMD-17 was correlated with a decrease in plasma ACTH, not in COR, by rTMS stimulation (p < 0.05).

CONCLUSION

Bilateral rTMS for 3 weeks palliated depression via improvement of sleep disorder, and plasma ACTH is a predictor for the efficacy of rTMS, especially in male patients with MDD.

Increased Prefrontal Activation During Verbal Fluency Task After Repetitive Transcranial Magnetic Stimulation Treatment in Depression: A Functional Near-Infrared Spectroscopy Study

BACKGROUND

Previous studies have shown the clinical effect of 2 Hz repetitive transcranial magnetic stimulation (rTMS) for depression; however, its underlying neural mechanisms are poorly understood. The aim of this study was to examine the effects of rTMS on the activity of the prefrontal cortex in patients with depression, using functional near-infrared spectroscopy (fNIRS).

METHODS

Forty patients with major depressive disorder (MDD) and 40 healthy controls were enrolled in this study. Patients underwent 4 weeks of 2 Hz TMS delivered to the right dorsolateral prefrontal cortex (DLPFC). fNIRS was used to measure the changes in the concentration of oxygenated hemoglobin ([oxy-Hb]) in the prefrontal cortex during a verbal fluency task (VFT) in depressed patients before and after rTMS treatment. The severity of depression was assessed using the Hamilton Rating Scale for Depression-24 item (HAMD-24).

RESULTS

Prior to rTMS, depressed patients exhibited significantly smaller [oxy-Hb] values in the bilateral prefrontal cortex during the VFT compared with the healthy controls. After 4 weeks of 2 Hz right DLPFC rTMS treatment, increased [oxy-Hb] values in the bilateral frontopolar prefrontal cortex (FPPFC), ventrolateral prefrontal cortex (VLPFC) and left DLPFC during the VFT were observed in depressed patients. The increased [oxy-Hb] values from baseline to post-treatment in the right VLPFC in depressed patients were positively related to the reduction of HAMD score following rTMS.

CONCLUSION

These findings suggest that the function of the prefrontal cortex in depressed patients was impaired and could be recovered by 2 Hz rTMS. The fNIRS-measured prefrontal activation during a cognitive task is a potential biomarker for monitoring depressed patients' treatment response to rTMS.

Glutamatergic System in Depression and Its Role in Neuromodulatory Techniques Optimization

Depressive disorders are among the most common psychiatric conditions and contribute to significant morbidity. Even though the use of antidepressants revolutionized the management of depression and had a tremendous positive impact on the patient's outcome, a significant proportion of patients with major depressive disorder (MDD) show no or partial or response even with adequate treatment. Given the limitations of the prevailing monoamine hypothesis-based pharmacotherapy, glutamate and glutamatergic related pathways may offer an alternative and a complementary option for designing novel intervention strategies. Over the past few decades, there has been a growing interest in understanding the neurobiological underpinnings of glutamatergic dysfunctions in the pathogenesis of depressive disorders and the development of new pharmacological and non-pharmacological treatment options. There is a growing body of evidence for the efficacy of neuromodulation techniques, including transcranial magnetic stimulation, transcutaneous direct current stimulation, transcranial alternating current stimulation, and photo-biomodulation on improving connectivity and neuroplasticity associated with depression. This review attempts to revisit the role of glutamatergic neurotransmission in the etiopathogenesis of depressive disorders and review the current neuroimaging, neurophysiological and clinical evidence of these neuromodulation techniques in the pathophysiology and treatment of depression.

Psychiatric Applications of Repetitive Transcranial Magnetic Stimulation

Transcranial magnetic stimulation (TMS) is an increasingly popular noninvasive brain stimulation modality. In TMS, a pulsed magnetic field is used to noninvasively stimulate a targeted brain region. Repeated stimulation produces lasting changes in brain activity via mechanisms of synaptic plasticity similar to long-term potentiation. Local application of TMS alters activity in distant, functionally connected brain regions, indicating that TMS modulates activity of cortical networks. TMS has been approved by the U.S. Food and Drug Administration for the treatment of major depressive disorder, obsessive-compulsive disorder, and smoking cessation, and a growing evidence base supports its efficacy in the treatment of other neuropsychiatric conditions. TMS is rapidly becoming part of the standard of care for treatment-resistant depression, where it yields response rates of 40%-60%. TMS is generally safe and well tolerated; its most serious risk is seizure, which occurs very rarely. This review aims to familiarize practicing psychiatrists with basic principles of TMS, including target localization, commonly used treatment protocols and their outcomes, and safety and tolerability. Practical considerations, including evaluation and monitoring of patients undergoing TMS, device selection, treatment setting, and insurance reimbursement, are also reviewed.

The Problem and Potential of TMS' Infinite Parameter Space: A Targeted Review and Road Map Forward

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive, effective, and FDA-approved brain stimulation method. However, rTMS parameter selection remains largely unexplored, with great potential for optimization. In this review, we highlight key studies underlying next generation rTMS therapies, particularly focusing on: (1) rTMS Parameters, (2) rTMS Target Engagement, (3) rTMS Interactions with Endogenous Brain Activity, and (4) Heritable Predisposition to Brain Stimulation Treatments.

METHODS

We performed a targeted review of pre-clinical and clinical rTMS studies.

RESULTS

Current evidence suggests that rTMS pattern, intensity, frequency, train duration, intertrain interval, intersession interval, pulse and session number, pulse width, and pulse shape can alter motor excitability, long term potentiation (LTP)-like facilitation, and clinical antidepressant response. Additionally, an emerging theme is how endogenous brain state impacts rTMS response. Researchers have used resting state functional magnetic resonance imaging (rsfMRI) analyses to identify personalized rTMS targets. Electroencephalography (EEG) may measure endogenous alpha rhythms that preferentially respond to personalized stimulation frequencies, or in closed-loop EEG, may be synchronized with endogenous oscillations and even phase to optimize response. Lastly, neuroimaging and genotyping have identified individual predispositions that may underlie rTMS efficacy.

CONCLUSIONS

We envision next generation rTMS will be delivered using optimized stimulation parameters to rsfMRI-determined targets at intensities determined by energy delivered to the cortex, and frequency personalized and synchronized to endogenous alpha-rhythms. Further research is needed to define the dose-response curve of each parameter on plasticity and clinical response at the group level, to determine how these parameters interact, and to ultimately personalize these parameters.

Optimal parameter determination of repetitive transcranial magnetic stimulation for treating treatment-resistant depression: A network meta-analysis of randomized controlled trials

BACKGROUND

Many studies have shown the efficacy of repetitive transcranial magnetic stimulation (rTMS) in treatment-resistant depression (TRD). However, the choice of different parameters has been a challenging issue.

METHODS

PubMed, Cochrane, and Embase databases were searched for relevant studies until June 20, 2022. The treatment efficacy was evaluated by the relative risk (RR) using the pairwise test for response and remission rates. Subgroup and sensitivity analyses were conducted to explore the primary outcome differences and to assess the reliability of the results.

RESULTS

Thirty-seven trials comprising 2120 participants with TRD were included. The more efficacious interventions compared to sham controls included high-frequency left followed by low-frequency right sup-threshold (HFL-LFR-sup-rTMS, RR = 5.29, 95% CI: 1.24-22.50), high-frequency left sup-threshold (HFL-sup-rTMS, RR = 2.97, 95% CI: 1.74-5.05), low-frequency right sup-threshold (LFR-sup-rTMS, RR = 2.72, 95% CI: 1.50-4.90), low-frequency right followed by high-frequency left sup-threshold (LFR-HFL-sup-rTMS, RR = 2.71, 95% CI: 1.62-4.53), and high-frequency left sub-threshold (HFL-sub-rTMS, RR = 1.91, 95% CI: 1.18-3.10) rTMS. The estimated relative ranking of treatments suggested that HFL-LFR-sup-rTMS (84.4%) might be the most efficacious among all rTMS strategies. No treatments showed a lower acceptability than the sham control.

LIMITATIONS

Subgroup analysis was not conducted to compare the efficacy of rTMS treatment between bipolar and unipolar depression, and small-study effects possibly introduced bias.

CONCLUSION

Treatment with HFL-LFR-sup-rTMS, HFL-sup-rTMS, LFR-sup-rTMS, LFR-HFL-sup-rTMS, or HFL-sub-rTMS is more efficacious than the sham control. HFL-LFR-sup-rTMS and HFL-sup-rTMS may be the two best among the most efficacious rTMS treatments.

SYSTEMATIC REVIEW REGISTRATION

[https://www.crd.york.ac.uk/PROSPERO], identifier [CRD42022334481].

Transcranial magnetic stimulation in the treatment of adolescent depression: a systematic review and meta-analysis of aggregated and individual-patient data from uncontrolled studies

Transcranial magnetic stimulation (TMS) is a non-invasive treatment for adolescent major depressive disorder (MDD). Existing evidence on the efficacy of TMS in adolescent MDD awaits quantitative synthesis. A systematic literature search was conducted, and data from eligible studies were synthesized using random-effects models. Treatment-covariate interactions were examined in exploratory analyses of individual-patient data (IPD). Systematic search of the literature yielded 1264 hits, of which 10 individual studies (2 randomized trials) were included for quantitative synthesis of mainly uncontrolled studies. Individual patient data (IPD) were available from five trials (all uncontrolled studies). Quantitative synthesis of aggregated data revealed a statistically significant negative overall standardized mean change (pooled SMCC = 2.04, 95% CI [1.46; 2.61], SE = 0.29, p < .001), as well as a significant overall treatment response rate (Transformed Proportion = 41.30%, 95% CI [31.03; 51.57], SE = 0.05; p < 0.001), considering data from baseline to post-treatment. Exploratory IPD analyses suggests TMS might be more effective in younger individuals and individuals with more severe depression, and efficacy might be enhanced with certain treatment modality settings, including higher number of TMS sessions, longer treatment durations, and unilateral and not bilateral stimulation. Existing studies exhibit methodological shortcomings, including small-study effects and lack of control group, blinding, and randomization-compromising the credibility of the present results. To date, two randomized controlled trials on TMS in adolescent depression have been published, and the only large-scale randomized trial suggests TMS is not more effective than sham stimulation. Future large-scale, randomized, and sham-controlled trials are warranted. Future trials should ensure appropriate selection of patients for TMS treatment and guide precision medicine approaches for stimulation protocols.

Neuromodulation Strategies for the Treatment of Depression

For many decades, psychiatric treatment has been primarily guided by two major paradigms of psychopathology: a neurochemical paradigm leading to the development of medications and a psychological paradigm resulting in the development of psychotherapies. A third paradigm positing that psychiatric dysfunction results from abnormal communication within a network of brain regions that regulate mood, thought, and behavior has gained increased attention over the past several years and underlies the development of multiple neuromodulation and neurostimulation therapies. This neural circuit paradigm is not new. In the late 19th and early 20th centuries, it was a common way of understanding psychiatric illness and led to several of our earliest somatic therapies. However, with the rise of effective medications and evidence-based psychotherapies, this paradigm went mostly dormant. Its recent reemergence resulted from a growing recognition that medications and psychotherapy leave many patients inadequately treated, along with technological advances that have revolutionized our ability to understand and modulate the neural circuitry involved in psychiatric disorders. In this overview, the authors review the history and current state of neuromodulation for psychiatric illness and specifically focus on these approaches as a treatment for depression, as this has been the primary indication for these interventions over time.

Adjunctive Nonconvulsive Electrotherapy for Patients with Depression: a Systematic Review

The efficacy and safety of adjunctive nonconvulsive electrotherapy (NET) for patients with depression are undetermined. This systematic review was conducted to examine the efficacy and safety of adjunctive NET for patients with depression. Chinese (WanFang and Chinese Journal Net) and English (PubMed, EMBASE, PsycINFO and the Cochrane Library) databases were systematically searched from their inception until Jan 27, 2021 by three independent investigators. One randomized controlled trial (RCT) with 3 treatment arms (n = 108) and two observational studies (single-group, before-after design, n = 31) were included. In the RCT, the antidepressant efficacy of NET on depression was similar to that of electroconvulsive therapy (ECT) (P > 0.05) but with significantly fewer neurocognitive impairments as measured by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) (P < 0.05). In two observational studies, the 17-item Hamilton Depression Rating Scale (HAMD-17) scores decreased significantly from baseline to post-NET (all Ps < 0.05), without adverse neurocognitive effects. In the RCT, adverse drug reactions (ADRs) were not separately reported among the 3 treatment arms but a similar rate of discontinuation was reported. The currently available limited evidence from 3 studies suggests that NET as an adjunctive treatment may be a safe, well-tolerated, effective therapy for depression without serious neurocognitive impairments.

Increasing Physical Activity among Breast Cancer Survivors by Modulating Temporal Orientation with rTMS: Feasibility and Potential Efficacy

Maintaining adequate amounts of physical activity is a critical component of survivorship care for women with breast cancer. Increased physical activity is associated with increases in well-being, quality of life, and longevity, but women with cancer face unique, cancer-related factors that might affect physical activity. Consistent with the Competing Neurobehavioral Decision Systems model of decision making, we proposed to decrease delay discounting and increase physical activity by stimulating the executive function system via high-frequency repetitive transcranial magnetic stimulation (HF rTMS) of the left dorsolateral prefrontal cortex (LDLPFC). This randomized, sham-controlled, double-blinded trial examined the feasibility and potential efficacy of this approach to increase physical activity in breast cancer survivors. We hypothesized that active rTMS would significantly increase the mean number of steps per day and decrease delay discounting. Participants (n = 30) were primarily middle-aged (M = 53.7, SD = 7.9) and white with a mean BMI and body mass indices below 40. Indicators of feasibility and limited efficacy testing were positive. Although repeated-measures ANOVA revealed no significant changes in delay discounting, generalized estimating equations (GEE) found that participants in the active condition increased their mean daily steps by 400 steps per day, while those in the sham condition decreased this by nearly 600 steps per day. These findings indicate that the continued investigation of HF rTMS for increasing physical activity among women with breast cancer is justified.

Transient Modulation of Working Memory Performance and Event-Related Potentials by Transcranial Static Magnetic Field Stimulation over the Dorsolateral Prefrontal Cortex

Transcranial static magnetic field stimulation (tSMS) can modulate human cortical excitability and behavior. To better understand the neuromodulatory effect of tSMS, this study investigates whether tSMS applied over the left dorsolateral prefrontal cortex (DLPFC) modulates working memory (WM) performance and its associated event-related potentials (ERPs). Thirteen healthy participants received tSMS or sham stimulation over the left DLPFC for 26 min on different days. The participants performed a 2-back version of the n-back task before, during (20 min after the start of stimulation), immediately after, and 15 min after the stimulation. We examine reaction time for correct responses, d-prime reflecting WM performance, and the N2 and P3 components of ERPs. Our results show that there was no effect of tSMS on reaction time. The d-prime was reduced, and the N2 latency was prolonged immediately after tSMS. These findings indicate that tSMS over the left DLPFC affects WM performance and its associated electrophysiological signals, which can be considered an important step toward a greater understanding of tSMS and its use in studies of higher-order cognitive processes.

Advances in repetitive transcranial magnetic stimulation for posttraumatic stress disorder: A systematic review

Repetitive transcranial magnetic stimulation (rTMS) as a treatment for posttraumatic stress disorder (PTSD) has gained interest over the past two decades. However, it has yet to be recommended in major treatment guidelines. We conducted a systematic review of randomized controlled trials to examine the efficacy of rTMS for PTSD. Thirteen studies with 549 participants were included in this review. We compared the effects of (1) rTMS versus sham, and (2) high-frequency (HF) versus low-frequency (LF) rTMS, on posttreatment PTSD scores and other secondary outcomes. We calculated the standardized mean differences (SMD) to determine the direction of effects, and unstandardized mean differences to estimate the magnitude of efficacy. At post-treatment, rTMS was superior to sham comparison in reducing PTSD (SMD = -1.13, 95% CI: -2.10 to -0.15) and depression severity (SMD = -0.83, 95% CI: -1.30 to -0.36). The quality of evidence, however, was rated very low due to small samples sizes, treatment heterogeneity, inconsistent results, and an imprecise pooled effect. HF rTMS was associated with slightly improved, albeit imprecise, outcomes compared to LF rTMS on PTSD (SMD = -0.19, 95% CI: -1.39 to 1.00) and depression (SMD = -1.09, 95% CI: -1.65 to -0.52) severity. Further research is required to advance the evidence on this treatment.

Prognostic neuroimaging biomarkers of trauma-related psychopathology: resting-state fMRI shortly after trauma predicts future PTSD and depression symptoms in the AURORA study

Neurobiological markers of future susceptibility to posttraumatic stress disorder (PTSD) may facilitate identification of vulnerable individuals in the early aftermath of trauma. Variability in resting-state networks (RSNs), patterns of intrinsic functional connectivity across the brain, has previously been linked to PTSD, and may thus be informative of PTSD susceptibility. The present data are part of an initial analysis from the AURORA study, a longitudinal, multisite study of adverse neuropsychiatric sequalae. Magnetic resonance imaging (MRI) data from 109 recently (i.e., ~2 weeks) traumatized individuals were collected and PTSD and depression symptoms were assessed at 3 months post trauma. We assessed commonly reported RSNs including the default mode network (DMN), central executive network (CEN), and salience network (SN). We also identified a proposed arousal network (AN) composed of a priori brain regions important for PTSD: the amygdala, hippocampus, mamillary bodies, midbrain, and pons. Primary analyses assessed whether variability in functional connectivity at the 2-week imaging timepoint predicted 3-month PTSD symptom severity. Left dorsolateral prefrontal cortex (DLPFC) to AN connectivity at 2 weeks post trauma was negatively related to 3-month PTSD symptoms. Further, right inferior temporal gyrus (ITG) to DMN connectivity was positively related to 3-month PTSD symptoms. Both DLPFC-AN and ITG-DMN connectivity also predicted depression symptoms at 3 months. Our results suggest that, following trauma exposure, acutely assessed variability in RSN connectivity was associated with PTSD symptom severity approximately two and a half months later. However, these patterns may reflect general susceptibility to posttraumatic dysfunction as the imaging patterns were not linked to specific disorder symptoms, at least in the subacute/early chronic phase. The present data suggest that assessment of RSNs in the early aftermath of trauma may be informative of susceptibility to posttraumatic dysfunction, with future work needed to understand neural markers of long-term (e.g., 12 months post trauma) dysfunction. Furthermore, these findings are consistent with neural models suggesting that decreased top-down cortico-limbic regulation and increased network-mediated fear generalization may contribute to ongoing dysfunction in the aftermath of trauma.

Accelerated transcranial magnetic stimulation (aTMS) to treat depression with treatment switching: study protocol of a pilot, randomized, delayed-start trial

Background

Repetitive transcranial magnetic stimulation (rTMS) is a technique for stimulating brain activity using a transient magnetic field to induce an electrical current in the brain producing depolarization of focal groups of brain cells. TMS is a protocol approved by the U.S. Food and Drug Administration in routine clinical practice as a treatment for depression. A major limitation of rTMS is the large amount of time taken for a standard protocol (38 min a day for 20–30 working days). The optimal type and duration of TMS are still uncertain, as is the optimal strategy for continuing or changing the type of rTMS if there is a poor initial response.

Objectives

The trial aims to assess whether a 1-week compressed course of left dorsolateral prefrontal (L DLPFC) 5 Hz accelerated rTMS (aTMS) treatment is as effective as an established 4-week course of non-accelerated rTMS and if additional 5 Hz L DLPFC aTMS treatments will be efficacious in non-responders as compared to 1 Hz right DLPFC aTMS treatment.

Methods

A randomized, single-blind, delayed-start trial was planned to commence in Jan 2020. A total of 60 patients will be enrolled from the Institute of Mental Health Singapore within a 2-year period and randomized into the early or delayed-start phase of the trial. The primary outcome of the trial is the improvement of Montgomery-Asberg Depression Rating scale at the end of the active treatment phase.

Discussion

If this study protocol proves to be effective, the findings of this trial will be updated to the College of Psychiatrists, Academy of Medicine Singapore, as well as published in a peer-reviewed journal to enhance local and international TMS treatment guidelines.

Trial registration

ClinicalTrials.gov ID: NCT03941106

Exploratory study on neurochemical effects of low-intensity pulsed ultrasound in brains of mice

There is now a relatively large body of evidence suggesting a relationship between dysfunction of myelin and oligodendrocytes and the etiology of several neuropsychiatric disorders, including depression and schizophrenia, and also suggesting that ultrasound methods may alleviate some of the symptoms of depression. We have applied low-intensity pulsed ultrasound (LIPUS) to the brains of mice treated with the demyelinating drug cuprizone, a drug that has been used as the basis for a rodent model relevant to a number of psychiatric and neurologic disorders including depression, schizophrenia, and multiple sclerosis. Prior to conducting the studies in mice, preliminary studies were carried out on the effects of LIPUS in vitro in neuron-like SH-SY5Y cells and primary glial cells. In subsequent studies in mice, female C57BL/6 mice were restrained in plastic tubes for 20 min daily with the ultrasound transducer near the end of the tube directly above the mouse's head. LIPUS was used at an intensity of 25 mW/cm² once daily for 22 days in control mice and in mice undergoing daily repetitive restraint stress (RRS). Behavioral or neurochemical studies were done on the mice or the brain tissue obtained from them. The studies in vitro indicated that LIPUS stimulation at an intensity of 15 mW/cm² delivered for 5 min daily for 3 days in an enclosed sterile cell culture plate in an incubator increased the viability of SH-SY5Y and primary glial cells. In the studies in mice, LIPUS elevated levels of doublecortin, a marker for neurogenesis, in the cortex compared to levels in the RRS mice and caused a trend in elevation of brain levels of brain-derived neurotrophic factor in the hippocampus relative to control levels. LIPUS also increased sucrose preference (a measure of the attenuation of anhedonia, a common symptom of several psychiatric disorders) in the RRS model in mice. The ability of LIPUS administered daily to rescue damaged myelin and oligodendrocytes was studied in mice treated chronically with cuprizone for 35 days. LIPUS increased cortex and corpus callosum levels of myelin basic protein, a protein marker for mature oligodendrocytes, and neural/glial antigen 2, a protein marker for oligodendrocyte precursor cells, relative to levels in the cuprizone + sham animals. These results of this exploratory study suggest that future comprehensive time-related studies with LIPUS on brain chemistry and behavior related to neuropsychiatric disorders are warranted. Exploratory Study on Neurochemical Effects of Low Intensity Pulsed Ultrasound in Brains of Mice. Upper part of figure: LIPUS device and in-vitro cell experimental set-up. The center image is the LIPUS generating box; the image in the upper left shows the cell experiment set-up; the image in the upper right shows a zoomed-in sketch for the cell experiment; the image in the lower left shows the set-up of repetitive restraint stress (RRS) with a mouse; the image in the lower middle shows the set-up of LIPUS treatment of a mouse; the image in the lower right shows a zoomed-in sketch for the LIPUS treatment of a mouse.

Optimized repetitive transcranial magnetic stimulation techniques for the treatment of major depression: A proof of concept study

Although effective in major depressive disorder (MDD), repetitive transcranial magnetic stimulation (rTMS) is costly and complex, limiting accessibility. To address this, we tested the feasibility of novel rTMS techniques with cost-saving opportunities, such as an open-room setting, large non-focal parabolic coils, and custom-built coil arms. We employed a low-frequency (LF) 1 Hz stimulation protocol (360 pulses per session), delivered on the most affordable FDA-approved device. MDD participants received an initial accelerated rTMS course (arTMS) of 6 sessions/day over 5 days (30 total), followed by a tapering course of daily sessions (up to 25) to decrease the odds of relapse. The self-reported Beck Depression Inventory II (BDI-II) was used to measure severity of depression. Forty-eight (48) patients completed the arTMS course. No serious adverse events occurred, and all patients reported manageable pain levels. Response and remission rates were 35.4% and 27.1% on the BDI-II, respectively, at the end of the tapering course. Repeated measures ANOVA showed significant changes of BDI-II scores over time. Even though our protocol will require further improvements, some of the concepts we introduced here could help guide the design of future trials aiming at increasing accessibility to rTMS.

A happiness magnet? Reviewing the evidence for repetitive transcranial magnetic stimulation in major depressive disorder

OBJECTIVES

First, to conduct a historical review of the evidence for repetitive transcranial magnetic stimulation (rTMS) for major depressive disorder and determine a clinical algorithm. Second, to identify opportunities for research.

METHODS

Literature searches were conducted of the MEDLINE database, UpToDate and the Australian National University Library SuperSearch from 1 January 2000 to 30 September 2019. The search terms used were 'transcranial magnetic stimulation', 'major depressive disorder' and 'depression'.

RESULTS

There were 24 meta-analyses identified, demonstrating a clear clinical effect. Left high-frequency rTMS had the most evidence. Ideal clinical parameters and study design were explored.

CONCLUSION

Use of rTMS for some patients with depression is justified. Open research questions include the comparative efficacy of right low-frequency and bilateral stimulation, the role of rTMS in medication-naïve patients, and maintenance of effect.

Repetitive Transcranial Magnetic Stimulation for Treatment-Resistant Depression: Recent Critical Advances in Patient Care

PURPOSE

Transcranial magnetic stimulation (TMS) is an evidence-based treatment for pharmacoresistant major depressive disorder (MDD). In the last decade, the field has seen significant advances in the understanding and use of this new technology. This review aims to describe the large, randomized controlled studies leading to the modern use of rTMS for MDD. It also includes a special section briefly discussing the use of these technologies during the COVID-19 pandemic.

RECENT FINDINGS

Several new approaches and technologies are emerging in this field, including novel approaches to reduce treatment time and potentially yield new approaches to optimize and maximize clinical outcomes. Of these, theta burst TMS now has evidence indicating it is non-inferior to standard TMS and provides significant advantages in administration. Recent studies also indicate that neuroimaging and related approaches may be able to improve TMS targeting methods and potentially identify those patients most likely to respond to stimulation.

SUMMARY

While new data is promising, significant research remains to be done to individualize and optimize TMS procedures. Emerging new approaches, such as accelerated TMS and advanced targeting methods, require additional replication and demonstration of real-world clinical utility. Cautious administration of TMS during the pandemic is possible with careful attention to safety procedures.

The more the merrier? Preliminary results regarding treatment duration and stimulation frequency of multisite repetitive transcranial magnetic stimulation in chronic tinnitus

The current study examines two different protocols of repetitive transcranial magnetic stimulation (rTMS) targeting three key hubs of cortical tinnitus networks. Patients chose whether they preferred to undergo rTMS treatment for 10 or 20 sessions and were randomized to the different rTMS protocols thereafter. Ninety patients were enrolled in the study with a total dropout rate of 10%. Both rTMS protocols were well tolerated by the patients without any serious adverse events. Overall treatment effects were small both for 2 weeks and 4 weeks of treatment. There was no significant interaction effect between measurement time point and treatment group for neither of the outcome measures nor any differences regarding the applied treatment regimens. The effects of this study contradict former observations suggesting multisite rTMS protocols as promising neuromodulatory strategies. This lack of effect could not be enhanced by increasing the number of treatment sessions in our study.