Safety and Efficacy of Continuous Theta Burst "Intensive" Stimulation in Acute-Phase Bipolar Depression: A Pilot, Exploratory Study

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.

Research on clinical aspects of bipolar disorder: A review of Indian studies

Background

Bipolar disorder is one of the severe mental disorders that are associated with significant morbidity of the patients. Despite advancements in our understanding about the disorder, it remains a challenging proposition to treat bipolar disorder, largely since the prophylactic treatment of the disorder requires assessment of complex clinical algorithms. The revisions of the classificatory systems have also changed the conceptualization of the disorder. In this background, we conducted a review of the Indian studies conducted on the clinical aspects of bipolar disorder.

Methods

A narrative review was conducted with focus on the literature published from India. The databases searched included PubMed, Scopus, and Google Scholar, and articles published over the last 15 years by Indian authors were included for this review.

Results

In our review, we could access a substantial volume of research published from India. We could identify studies that catered to most of the relevant themes in bipolar disorder including epidemiology, etiology, comorbidities, stigma, disability, clinical course, cognitive profile, pathways to care, and recovery.

Conclusion

The research trajectory was in line with the research conducted elsewhere in the world. However, certain dissimilarities in terms of focus could also be observed. The possible reason behind this deviation could be the difference in clinical need and unique challenges faced in the management and rehabilitation of patients in bipolar disorder in Indian scenario.

Adjunctive continuous theta burst stimulation for major depressive disorder or bipolar depression: A meta-analysis of randomized controlled studies

OBJECTIVES

As a novel type of theta burst stimulation (TBS), continuous TBS (cTBS) has been shown to have mixed therapeutic effects for major depressive disorder (MDD) or bipolar depression (BD). Thus, we performed a meta-analysis of randomized controlled trials (RCTs) of cTBS for treating major depressive episodes in patients with MDD or BD.

METHODS

A systematic search of four major bibliographic databases (PubMed, EMBASE, Cochrane Library, and PsycINFO) was conducted from inception dates to February 3, 2023 to identify eligible studies. The data were analyzed using a random-effects model.

RESULTS

Three RCTs (n = 78, active cTBS = 37 and sham cTBS = 41) were included the meta-analysis. No significant differences were found in terms of change in Hamilton Depression Rating Scale (HAMD) scores (3 RCTs, n = 78, SMD = -0.09, 95 % CI: -0.53 to 0.36; I2 = 0 %; P = 0.71) and study-defined response (2 RCTs, n = 58, 26.7 % versus 21.4 %, RR = 1.20, 95 % CI: 0.48 to 2.96; I2 = 0 %; P = 0.70) between active and sham cTBS groups. Similarly, no group differences were found in the rates of adverse events and discontinuation due to any reason (P > 0.05).

LIMITATIONS

Meta-analysis had small sample sizes and low number of included studies.

CONCLUSIONS

Although cTBS appeared to be a safe and well-tolerated option for treating major depressive episodes in MDD or BD patients, no advantage in treatment effects was found in this meta-analysis. Future large-scale studies are warranted to assess the efficacy of cTBS for MDD or BD patients with a major depressive episode.

Comparing different non-invasive brain stimulation interventions for bipolar depression treatment: A network meta-analysis of randomized controlled trials

Non-invasive brain stimulation (NIBS) is a promising treatment for bipolar depression. We systematically searched for randomized controlled trials on NIBS for treating bipolar depression (INPLASY No: 202340019). Eighteen articles (N = 617) were eligible for network meta-analysis. Effect sizes were reported as standardized mean differences (SMDs) or odds ratios (ORs) with 95% confidence intervals (CIs). Anodal transcranial direct current stimulation over F3 plus cathodal transcranial direct current stimulation over F4 (a-tDCS-F3 +c-tDCS-F4; SMD = -1.18, 95%CIs = -1.66 to -0.69, N = 77), high-definition tDCS over F3 (HD-tDCS-F3; -1.17, -2.00 to -0.35, 25), high frequency deep transcranial magnetic stimulation (HF-dTMS; -0.81, -1.62 to -0.001, 25), and high frequency repetitive TMS over F3 plus low frequency repetitive TMS over F4 (HF-rTMS-F3 +LF-rTMS-F4; -0.77, -1.43 to -0.11, 38) significantly improved depressive symptoms compared to sham controls. Only a-tDCS-F3 +c-tDCS-F4 (OR = 4.53, 95%CIs = 1.51-13.65) and HF-rTMS-F3 +LF-rTMS-F4 (4.69, 1.02-21.56) showed higher response rates. No active NIBS interventions exhibited significant differences in dropout or side effect rates, compared with sham controls.

Evidence from Indian studies on safety and efficacy of therapeutic transcranial magnetic stimulation across neuropsychiatric disorders- A systematic review and meta-analysis

Repetitive transcranial magnetic stimulation (rTMS) is potentially effective as an augmentation strategy in the treatment of many neuropsychiatric conditions. Several Indian studies have been conducted in this regard. We aimed to quantitatively synthesize evidence from Indian studies assessing efficacy and safety of rTMS across broad range of neuropsychiatric conditions. Fifty two studies- both randomized controlled and non-controlled studies were included for a series of random-effects meta-analyses. Pre-post intervention effects of rTMS efficacy were estimated in "active only" rTMS treatment arms/groups and "active vs sham" (sham-controlled) studies using pooled Standardized Mean Differences (SMDs). The outcomes were 'any depression', depression in unipolar/bipolar depressive disorder, depression in obsessive compulsive disorder (OCD), depression in schizophrenia, schizophrenia symptoms (positive, negative, total psychopathology, auditory hallucinations and cognitive deficits), obsessive compulsive symptoms of OCD, mania, craving/compulsion in substance use disorders (SUDs) and migraine (headache severity and frequency). Frequencies and odds ratios (OR) for adverse events were calculated. Methodological quality of included studies, publication bias and sensitivity assessment for each meta-analyses was conducted. Meta-analyses of "active only" studies suggested a significant effect of rTMS for all outcomes, with moderate to large effect sizes, at both end of treatment as well as at follow-up. However, except for migraine (headache severity and frequency) with large effect sizes at end of treatment only and craving in alcohol dependence where moderate effect size at follow-up only, rTMS was not found to be effective for any outcome in the series of "active vs sham" meta-analyses. Significant heterogeneity was seen. Serious adverse events were rare. Publication bias was common and the sham controlled positive results lost significance in sensitivity analysis. We conclude that rTMS is safe and shows positive results in 'only active' treatment groups for all the studied neuropsychiatric conditions. However, the sham-controlled evidence for efficacy is negative from India.

Conclusion

rTMS is safe and shows positive results in "only active" treatment groups for all the studied neuropsychiatric conditions. However, the sham-controlled evidence for efficacy is negative from India.