Comparison of clinical outcomes with left unilateral and sequential bilateral Transcranial Magnetic Stimulation (TMS) treatment of major depressive disorder in a large patient registry

Continuous theta burst stimulation for bipolar depression: A multicenter, double-blind randomized controlled study exploring treatment efficacy and predictive potential of kynurenine metabolites

BACKGROUND

While theta burst stimulation (TBS) shows promise in Major Depressive Disorder (MDD), its effectiveness in bipolar depression (BD-D) remains uncertain. Optimizing treatment parameters is crucial in the pursuit of rapid symptom relief. Moreover, aligning with personalized treatment strategies and increased interest in immunopsychiatry, biomarker-based stratification of patients most likely to benefit from TBS might improve remission rates. We investigated treatment effectiveness of continuous TBS (cTBS) compared to sham in BD-D, and assessed the capacity of plasma kynurenine pathway metabolites to predict treatment outcome.

METHODS

Thirty-seven patients with BD-D underwent accelerated active or sham cTBS treatment in a multicenter, double-blind, randomized controlled trial. Depressive symptoms were measured with the 17-item Hamilton Depression Rating Scale (HDRS-17) before treatment (T0), 3-4 days posttreatment (T1) and 10-11 days posttreatment (T2). Plasma tryptophan, kynurenine, kynurenic acid and quinolinic acid concentrations were quantified with ELISA. Linear mixed models were used for statistical analyses.

RESULTS

Although the total sample showed depressive symptom improvement, active cTBS did not demonstrate greater symptom alleviation compared to sham. However, higher baseline quinolinic acid significantly predicted symptom improvement in the active treatment group, not in sham-stimulated patients.

LIMITATIONS

The modest sample size limited the power to detect significant differences with regard to treatment effect. Also, the follow-up period was 10-11 days, whereas similar studies usually follow up for at least one month.

CONCLUSION

More research is required to optimize cTBS for BD-D and explore the involvement of quinolinic acid in treatment outcome.

Update on the assessment of resistance to antidepressant treatment: Rationale for the Antidepressant Treatment History Form: Short Form-2 (ATHF-SF2)

All definitions of treatment-resistant depression (TRD) require that patients have experienced insufficient benefit from one or more adequate antidepressant trials. Thus, identifying "failed, adequate trials" is key to the assessment of TRD. The Antidepressant Treatment History Form (ATHF) was one of the first and most widely used instruments that provided objective criteria in making these assessments. The original ATHF was updated in 2018 to the ATHF-SF, changing to a checklist format for scoring, and including specific pharmacotherapy, brain stimulation, and psychotherapy interventions as potentially adequate antidepressant treatments. The ATHF-SF2, presented here, is based on the consensus of the ATHF workgroup about the novel interventions introduced since the last revision and which should/should not be considered effective treatments for major depressive episodes. This document describes the rationale for these choices and, for each intervention, the minimal criteria for determining the adequacy of treatment administration. The Supplementary Material that accompanies this article provide the Scoring Checklist, Data Collection Forms (current episode and composite of previous episodes), and Instruction Manual for the ATHF-SF2.

Older age associated with better antidepressant response to H1-coil transcranial magnetic stimulation in female patients

BACKGROUND

TMS is increasingly used to treat depression, but predictors of treatment outcomes remain unclear. We assessed the association between age and TMS response given inconsistent prior reports limited by small sample size, heterogeneity, outdated TMS parameters, lack of assessment of H1-coil TMS, and lack of an a priori hypothesis. We hypothesized that older age would be associated with better treatment response based on trends in recent large exploratory analyses.

METHODS

We conducted a naturalistic retrospective analysis of patients (n = 378) ages 18-80 with depression (baseline Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR) > 5) who received 29-35 sessions of TMS between 2014 and 2021. Response was assessed using percent reduction of QIDS-SR. The relationship between percent response or remission and age group was assessed using the chi-square test.

RESULTS

85 % of patients received the standard protocol of H1-coil TMS to the left DLPFC. Percent response and remission rates for the entire study sample increased with age (response: p = .026; remission: p = .0023). This finding was stronger in female patients (response: p = .0033; remission: p = .00098) and was not observed in male patients (response: p = .73; remission: p = .26). This was confirmed in a sub-analysis of patients who only received the standard protocol with the H1-coil for the entire treatment course.

LIMITATIONS

Naturalistic retrospective analysis from one academic center.

CONCLUSIONS

Older age is associated with a better antidepressant response to H1-coil TMS in female patients. This was demonstrated in a hypothesis-driven confirmation of prior exploratory findings in a large sample size with a homogeneous data collection protocol across all participants.

When to hold and when to fold: Early prediction of nonresponse to transcranial magnetic stimulation in major depressive disorder

BACKGROUND

Determining when to recommend a change in treatment regimen due to insufficient improvement is a common challenge in therapeutics.

METHODS

In a sample of 7215 patients with major depressive disorder treated with transcranial magnetic stimulation (TMS) and with PHQ-9 scores before, during and after the course, 3 groups were identified based on number of acute course sessions: exactly 36 sessions (N = 3591), more than 36 sessions (N = 975), and less than 36 sessions (N = 2649). Two techniques were used to determine thresholds for percentage change in PHQ-9 scores at assessments after 10, 20, and 30 sessions that optimized prediction of endpoint response status: the Youden index and fixing the false positive rate at 10%. Positive and negative predictive values were calculated to assess the accuracy of identifying final nonresponders and responders, respectively.

RESULTS

There was greater accuracy in predicting final response than nonresponse, especially in the groups that had at least 36 sessions. Substantial proportions of patients with low levels of early improvement were classified as responders at the end of treatment.

LIMITATIONS

The findings should be validated with clinician ratings using a more comprehensive depression severity scale.

CONCLUSIONS

Manifesting clinical improvement early in the TMS course is strongly predictive of final status as a responder, while lack of early improvement is a relatively poor indicator of final nonresponse status. The predictive value of lack of early symptomatic improvement is too low to make reliable recommendations regarding changes in treatment regimen.

Bilateral rTMS Shows No Advantage in Depression nor in Comorbid Depression and Anxiety: A Naturalistic Study

The objective was to determine if adding low-frequency right-sided rTMS treatment to the standard high-frequency left-sided treatment (LUL), referred to as sequential bilateral treatment (SBT), confers additional benefit for depression or anxiety outcomes. A retrospective chart review from January 2015 through December 2018 yielded 275 patients, all of whom were treated with a figure-8 coil for a major depressive episode. Their protocol was either LUL or SBL. Outcome measures were the Generalized Anxiety Disorder 7-item scale (GAD-7) and the Patient Health Questionnaire (PHQ-9). There was no significant difference in GAD-7 change scores between patients who had LUL or SBL (4.2 vs 4.8). This was also true when the sample was restricted to only patients who started with high GAD-7 scores. There was likewise no significant difference in PHQ-9 change scores between patients who had LUL or SBL (6.8 vs 5.1). Patients switching from LUL to SBL mid-course had poorer overall outcomes as compared to patients who stayed with the same protocol throughout treatment. This large naturalistic study shows no advantage for SBL treatment any group or condition examined. The results of this study have clinical applicability and sound a cautionary note regarding the use of combination rTMS protocols.

Evaluating real-world effectiveness of accelerated transcranial magnetic stimulation for treatment-resistant depression in a tertiary referral center based in Quebec, Canada

OBJECTIVE

To assess the effectiveness of accelerated transcranial magnetic stimulation (TMS) for treatment-resistant depression (TRD) in a tertiary referral center in Quebec, Canada, focusing on a real-world clinical setting.

METHODS

We reviewed the data of 247 TRD patients treated between January 2012 and May 2022 who received accelerated TMS. Participants were adults diagnosed with unipolar or bipolar depression, resistant to at least two antidepressant trials, and assessed using the Montgomery-Åsberg Depression Rating Scale (MADRS).

RESULTS

Significant symptom reduction was found in the completer sample (N = 147), with 46.3 % of patients meeting post-treatment response criteria and 36.1 % achieving remission. Baseline severity of depression, age, and the number of antidepressant trials were key predictors of treatment outcomes. Patients who did not complete treatment had generally more severe depressive and anxious symptoms and greater treatment resistance. No significant differences in response rates were observed across different TMS coils.

CONCLUSION

The study demonstrated the effectiveness and tolerability of accelerated TMS for TRD in a real-world clinical setting.

Accelerated TMS - moving quickly into the future of depression treatment

Accelerated TMS is an emerging application of Transcranial Magnetic Stimulation (TMS) aimed to reduce treatment length and improve response time. Extant literature generally shows similar efficacy and safety profiles compared to the FDA-cleared protocols for TMS to treat major depressive disorder (MDD), yet accelerated TMS research remains at a very early stage in development. The few applied protocols have not been standardized and vary significantly across a set of core elements. In this review, we consider nine elements that include treatment parameters (i.e., frequency and inter-stimulation interval), cumulative exposure (i.e., number of treatment days, sessions per day, and pulses per session), individualized parameters (i.e., treatment target and dose), and brain state (i.e., context and concurrent treatments). Precisely which of these elements is critical and what parameters are most optimal for the treatment of MDD remains unclear. Other important considerations for accelerated TMS include durability of effect, safety profiles as doses increase over time, the possibility and advantage of individualized functional neuronavigation, use of biological readouts, and accessibility for patients most in need of the treatment. Overall, accelerated TMS appears to hold promise to reduce treatment time and achieve rapid reduction in depressive symptoms, but at this time significant work remains to be done. Rigorous clinical trials combining clinical outcomes and neuroscientific measures such as electroencephalogram, magnetic resonance imaging and e-field modeling are needed to define the future of accelerated TMS for MDD.

A naturalistic study comparing the efficacy of unilateral and bilateral sequential theta burst stimulation in treating major depression - the U-B-D study protocol

BACKGROUND

Major depressive disorder (MDD) is a prevalent mental health condition affecting millions worldwide, leading to disability and reduced quality of life. MDD poses a global health priority due to its early onset and association with other disabling conditions. Available treatments for MDD exhibit varying effectiveness, and a substantial portion of individuals remain resistant to treatment. Repetitive transcranial magnetic stimulation (rTMS), applied to the left and/or right dorsolateral prefrontal cortex (DLPFC), is an alternative treatment strategy for those experiencing treatment-resistant MDD. The objective of this study is to investigate whether this newer form of rTMS, namely theta burst stimulation (TBS), when performed unilaterally or bilaterally, is efficacious in treatment-resistant MDD.

METHODS

In this naturalistic, randomized double-blinded non-inferiority trial, participants with a major depressive episode will be randomized to receive either unilateral (i.e., continuous TBS [cTBS] to the right and sham TBS to the left DLPFC) or bilateral sequential TBS (i.e., cTBS to the right and intermittent TBS [iTBS] to the left DLPFC) delivered 5 days a week for 4-6 weeks. Responders will move onto a 6-month flexible maintenance phase where TBS treatment will be delivered at a decreasing frequency depending on degree of symptom mitigation. Several clinical assessments and neuroimaging and neurophysiological biomarkers will be collected to investigate treatment response and potential associated biomarkers. A non-inferiority analysis will investigate whether bilateral sequential TBS is non-inferior to unilateral TBS and regression analyses will investigate biomarkers of treatment response. We expect to recruit a maximal of 256 participants. This trial is approved by the Research Ethics Board of The Royal's Institute of Mental Health Research (REB# 2,019,071) and will follow the Declaration of Helsinki. Findings will be published in peer-reviewed journals.

DISCUSSION

Comprehensive assessment of symptoms and neurophysiological biomarkers will contribute to understanding the differential efficacy of the tested treatment protocols, identifying biomarkers for treatment response, and shedding light into underlying mechanisms of TBS. Our findings will inform future clinical trials and aid in personalizing treatment selection and scheduling for individuals with MDD.

TRIAL REGISTRATION

The trial is registered on https://clinicaltrials.gov/ct2/home (#NCT04142996).

Dosing transcranial magnetic stimulation in major depressive disorder: Relations between number of treatment sessions and effectiveness in a large patient registry

BACKGROUND

The number of sessions in an acute TMS course for major depressive disorder (MDD) is greater than in the earlier randomized controlled trials.

OBJECTIVE

To compare clinical outcomes in groups that received differing numbers of TMS sessions.

METHODS

From a registry sample (N = 13,732), data were extracted for 7215 patients treated for MDD with PHQ-9 assessments before and after their TMS course. Groups were defined by number of acute course treatment sessions: 1-19 (N = 658), 20-29 (N = 616), 30-35 (N = 1375), 36 (N = 3591), 37-41 (N = 626), or >41 (N = 349) and compared in clinical outcomes at endpoint and at fixed intervals (after 10, 20, 30, and 36 sessions). The impact of additional treatments beyond 36 sessions was also examined.

RESULTS

Groups that received fewer than 30 sessions had inferior endpoint outcomes than all other groups. PHQ-9 symptom reduction was greatest in the group that ended treatment at 36 sessions. The extended treatment groups (>36 sessions) differed from all other groups by manifesting less antidepressant response early in the course and had a slower but steady rate of improvement over time. Extending treatment beyond 36 sessions was associated with further improvement without evidence of a plateau.

CONCLUSIONS

In real-world practice, there are strong relations between the number of TMS sessions in a course and the magnitude of symptom reduction. Courses with less than 30 sessions are associated with diminished benefit. Patients with longer than standard courses typically show less initial improvement and a more gradual trajectory, but meaningful benefit accrues with treatment beyond 36 sessions.

Electric field distribution predicts efficacy of accelerated intermittent theta burst stimulation for late-life depression

Introduction

Repetitive transcranial magnetic stimulation (rTMS) is a promising intervention for late-life depression (LLD) but may have lower rates of response and remission owing to age-related brain changes. In particular, rTMS induced electric field strength may be attenuated by cortical atrophy in the prefrontal cortex. To identify clinical characteristics and treatment parameters associated with response, we undertook a pilot study of accelerated fMRI-guided intermittent theta burst stimulation (iTBS) to the right dorsolateral prefrontal cortex in 25 adults aged 50 or greater diagnosed with LLD and qualifying to receive clinical rTMS.

Methods

Participants underwent baseline behavioral assessment, cognitive testing, and structural and functional MRI to generate individualized targets and perform electric field modeling. Forty-five sessions of iTBS were delivered over 9 days (1800 pulses per session, 50-min inter-session interval). Assessments and testing were repeated after 15 sessions (Visit 2) and 45 sessions (Visit 3). Primary outcome measure was the change in depressive symptoms on the Inventory of Depressive Symptomatology-30-Clinician (IDS-C-30) from Visit 1 to Visit 3.

Results

Overall there was a significant improvement in IDS score with the treatment (Visit 1: 38.6; Visit 2: 31.0; Visit 3: 21.3; mean improvement 45.5%) with 13/25 (52%) achieving response and 5/25 (20%) achieving remission (IDS-C-30 < 12). Electric field strength and antidepressant effect were positively correlated in a subregion of the ventrolateral prefrontal cortex (VLPFC) (Brodmann area 47) and negatively correlated in the posterior dorsolateral prefrontal cortex (DLPFC).

Conclusion

Response and remission rates were lower than in recently published trials of accelerated fMRI-guided iTBS to the left DLPFC. These results suggest that sufficient electric field strength in VLPFC may be a contributor to effective rTMS, and that modeling to optimize electric field strength in this area may improve response and remission rates. Further studies are needed to clarify the relationship of induced electric field strength with antidepressant effects of rTMS for LLD.

Association between daily dose and efficacy of rTMS over the left dorsolateral prefrontal cortex in depression: A meta-analysis

Repetitive transcranial magnetic stimulation (rTMS) is a well-established, safe, and effective brain stimulation technique for depression; however, uniform parameters have not been used in clinical practice. The aim of this study was to identify the parameters that affect rTMS effectiveness and ascertain the range in which that parameter has optimal efficacy. A meta-analysis of sham-controlled trials using rTMS delivered over the left dorsolateral prefrontal cortex (DLPFC) in depression was conducted. In the meta-regression and subgroup analyses, all rTMS stimulation parameters were extracted and their association with efficacy was investigated. Of the 17,800 references, 52 sham-controlled trials were included. Compared to sham controls, our results demonstrated a significant improvement in depressive symptoms at the end of treatment. According to the results of meta-regression, the number of pulses and sessions per day correlated with rTMS efficacy; however, the positioning method, stimulation intensity, frequency, number of treatment days, and total pulses did not. Furthermore, subgroup analysis revealed that the efficacy was correspondingly better in the group with higher daily pulses. In clinical practice, increasing the number of daily pulses and sessions may improve the effectiveness of rTMS.

Accelerated Repetitive Transcranial Magnetic Stimulation to Treat Major Depression: The Past, Present, and Future

Repetitive transcranial magnetic stimulation (rTMS) is an effective and evidence-based therapy for treatment-resistant major depressive disorder. A conventional course of rTMS applies 20-30 daily sessions over 4-6 weeks. The schedule of rTMS delivery can be accelerated by applying multiple stimulation sessions per day, which reduces the duration of a treatment course with a predefined number of sessions. Accelerated rTMS reduces time demands, improves clinical efficiency, and potentially induces faster onset of antidepressant effects. However, considerable heterogeneity exists across study designs. Stimulation protocols vary in parameters such as the stimulation target, frequency, intensity, number of pulses applied per session or over a course of treatment, and duration of intersession intervals. In this article, clinician-researchers and neuroscientists who have extensive research experience in accelerated rTMS synthesize a consensus based on two decades of investigation and development, from early studies ("Past") to contemporaneous theta burst stimulation, a time-efficient form of rTMS gaining acceptance in clinical settings ("Present"). We propose descriptive nomenclature for accelerated rTMS, recommend avenues to optimize therapeutic and efficiency potential, and suggest using neuroimaging and electrophysiological biomarkers to individualize treatment protocols ("Future"). Overall, empirical studies show that accelerated rTMS protocols are well tolerated and not associated with serious adverse effects. Importantly, the antidepressant efficacy of accelerated rTMS appears comparable to conventional, once daily rTMS protocols. Whether accelerated rTMS induces antidepressant effects more quickly remains uncertain. On present evidence, treatment protocols incorporating high pulse dose and multiple treatments per day show promise and improved efficacy.

A Systematic Review Assessing Patient-Related Predictors of Response to Transcranial Magnetic Stimulation in Major Depressive Disorder

Objective

The safety and efficacy of transcranial magnetic stimulation (TMS) in the acute treatment of major depressive disorder (MDD) is well established. However, it is not well understood which patient-related factors are associated with a more robust antidepressant response. Identifying predictive factors for therapeutic response to TMS treatment in depression will guide clinicians in patient selection.

Methods

By systematic review of clinical trial data, the current study aims to identify and analyze reported patient-specific predictors of response to an acute course of TMS treatment for MDD. PubMed was searched for randomized controlled trials of TMS for patients with depression. Studies were appraised for risk of bias using components recommended by the Cochrane Collaboration and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Results

TMS data were available from 375 studies, 18 of which were included in this review. Treatment response is inversely associated with treatment refractoriness and age.

Conclusion

Inadequate sample size and large heterogeneity in study parameters among clinical trials limit any strong conclusions from being drawn; nonetheless, despite these limitations, there is mounting evidence, which points to age and treatment refractoriness as candidate variables for predicting clinical outcome. Implications of these findings for treatment of MDD are discussed.

Effectiveness of Standard Sequential Bilateral Repetitive Transcranial Magnetic Stimulation vs Bilateral Theta Burst Stimulation in Older Adults With Depression: The FOUR-D Randomized Noninferiority Clinical Trial

IMPORTANCE

Treatment-resistant depression (TRD) is common in older adults. Bilateral repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex for 48 minutes has demonstrated efficacy in TRD. Theta burst stimulation (TBS), a newer form of rTMS, can also be delivered bilaterally using left intermittent TBS and right continuous TBS for only 4 minutes.

OBJECTIVE

To establish the effectiveness and tolerability of TBS compared with standard rTMS in older adults with TRD.

DESIGN, SETTING, AND PARTICIPANTS

In this randomized noninferiority trial with open treatment and blinded assessors, recruitment occurred between December 2016 and March 2020. The trial was conducted at the Centre for Addiction and Mental Health in Toronto, Ontario, Canada and included outpatients 60 years and older with a diagnosis of depression, moderate severity, and nonresponse to 1 or more antidepressant trial of adequate dosage and duration or intolerance of 2 or more trials.

INTERVENTIONS

Participants were randomized to receive a course of 4 to 6 weeks of either bilateral standard rTMS or TBS.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was change in Montgomery-Åsberg Depression Rating Scale; secondary outcome measures included the 17-item Hamilton Rating Scale for Depression, Quick Inventory of Depressive Symptomatology (16-item) (self-report), and dropout rates. A noninferiority margin of 2.75 points was used for the primary outcome. All participants who attained the primary completion point of 4 weeks were analyzed.

RESULTS

A total of 87 participants (mean [SD] age, 67.1 [6.7] years; 47 [54.0%] female) were randomized to standard bilateral rTMS and 85 (mean [SD] age, 66.3 [5.3] years; 45 [52.9%] female) to TBS, of whom 85 (98%) and 79 (93%) were assessed for the primary outcome, respectively, whereas tolerability was assessed in all randomized participants. In the rTMS group, 4 (4.6%) were American Indian, reported other, or preferred not to answer; 5 (5.8%) were Asian; and 78 (89.7%) were White. In the TBS group, 6 (7.1%) were Asian, 2 (2.4%) were Black or reported other, and 77 (90.3%) were White. Mean (SD) Montgomery-Åsberg Depression Rating Scale total scores improved from 25.6 (4.0) to 17.3 (8.9) for rTMS and 25.7 (4.7) to 15.8 (9.1) for TBS (adjusted difference, 1.55; lower 95% CI -0.67), establishing noninferiority for TBS. The all-cause dropout rates were relatively similar between groups (rTMS: 2 of 87 [2.3%]; TBS: 6 of 85 [7.1%]; P = .14; χ2 = 2.2).

CONCLUSIONS AND RELEVANCE

In older adults with TRD, bilateral TBS compared with standard bilateral rTMS achieved noninferior reduction in depression symptoms. Both treatments had low and similar dropout rates. Using TBS rather than rTMS could increase access to treatment several-fold for older adults with TRD.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02998580.

Deep Brain Stimulation for Depression

Deep brain stimulation has been extensively studied as a therapeutic option for treatment-resistant depression (TRD). DBS across different targets is associated with on average 60% response rates in previously refractory chronically depressed patients. However, response rates vary greatly between patients and between studies and often require extensive trial-and-error optimizations of stimulation parameters. Emerging evidence from tractography imaging suggests that targeting combinations of white matter tracts, rather than specific grey matter regions, is necessary for meaningful antidepressant response to DBS. In this article, we review efficacy of various DBS targets for TRD, which networks are involved in their therapeutic effects, and how we can use this information to improve targeting and programing of DBS for individual patients. We will also highlight how to integrate these DBS network findings into developing adaptive stimulation and optimal trial designs.