Multimodal Elements of Suicidality Reduction After Transcranial Magnetic Stimulation

Psychoneuroimmunoendocrinological and neuroanatomical basis of suicidal behavior: potential therapeutic strategies with a focus on transcranial magnetic stimulation (TMS)

Suicidal behavior is a complex phenomenon influenced by psychological, environmental, and biological factors. It affects a significant portion of the global population, with more than 720,000 deaths annually and millions of individuals experiencing suicidal ideation. Among those who attempt suicide, only a fraction progresses to a fatal outcome, emphasizing the importance of understanding individual vulnerabilities. This review explores the neuroanatomical basis of suicidal behavior, focusing on key brain regions and potential pathways for neuromodulation therapies, particularly Transcranial Magnetic Stimulation (TMS). The dorsolateral prefrontal cortex (DLPFC) plays a central role in cognitive control and emotional regulation, with extensive connections to the anterior cingulate cortex, amygdala, orbitofrontal cortex, hippocampus, and thalamus. Dysfunctions in these circuits contribute to heightened impulsivity, impaired decision-making, and emotional dysregulation in individuals with suicidal behavior. Structural and functional abnormalities in the DLPFC, coupled with altered neurotransmitter systems and inflammatory markers, have been consistently linked to suicidality. TMS, targeting the left DLPFC, has shown promise in reducing suicidal ideation by modulating frontostriatal connectivity, enhancing neuroplasticity, and improving cortical excitability. High-frequency TMS and accelerated theta-burst stimulation protocols demonstrate rapid therapeutic effects, though further research is needed to establish standardized treatment guidelines. Understanding the anatomical circuits implicated in suicidal behavior provides valuable insights for early risk assessment and the development of targeted neuromodulation interventions aimed at reducing the burden of suicide across diverse psychiatric populations.

Frontal Pole Neuromodulation for Impulsivity and Suicidality in Veterans With Mild Traumatic Brain Injury and Common Co-Occurring Mental Health Conditions: Protocol for a Pilot Randomized Controlled Trial

BACKGROUND

Suicide remains a leading cause of death among veterans in the United States, and mild traumatic brain injury (mTBI) increases the risk of suicidal ideation (SI) and suicide attempts (SAs). mTBI worsens impulsivity and contributes to poor social and occupational functioning, which further increases the risk of SI and SAs. Repetitive transcranial magnetic stimulation is a neuromodulatory treatment approach that induces neuroplasticity, potentially repairing neurodamage. Intermittent theta burst stimulation (iTBS) is a second-generation form of transcranial magnetic stimulation that is safe, shorter in duration, displays a minimal side effect profile and is a promising treatment approach for impulsivity in mTBI. Our novel proposed treatment protocol uses frontal pole iTBS to target the ventromedial prefrontal cortex, which may reduce impulsivity by strengthening functional connectivity between the limbic system and frontal cortex, allowing for improved top-down control of impulsive reactions, including SI and SAs.

OBJECTIVE

The objectives of this study are to (1) develop an iTBS intervention for veterans with mTBI, impulsivity, and SI; (2) assess the feasibility and tolerability of the intervention; and (3) gather preliminary clinical outcome data on SI, impulsivity, and functions that will guide future studies.

METHODS

This is a pilot, double-blinded, randomized controlled trial. In developing this protocol, we referenced the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) guidelines. We will enroll 56 participants (28 active iTBS and 28 sham iTBS). The iTBS intervention will be performed daily, 5 days a week, for 2 weeks. We will collect 10 validated, psychometric, quantitative outcome measures before, during, and after the intervention. Measures included will assess functioning, impulsivity, suicidality, posttraumatic stress disorder, and depressive symptoms. We will collect qualitative data through semistructured interviews to elicit feedback on the participants' experiences and symptoms. We will perform quantitative and qualitative analyses to (1) assess the feasibility, tolerability, and acceptability of the treatment; (2) gather advanced neuroimaging data to assess neural changes elicited by treatment; and (3) assess improvements in outcome measures of impulsivity and suicidality in veterans with mTBI.

RESULTS

This study protocol was approved by the Edward Hines, Jr. VA Hospital Institutional Review Board (Hines IRB number 14-003). This novel treatment is a 5-year research project (April 1, 2023, to March 31, 2028) funded by the Veterans Administration Rehabilitation Research and Development service (CDA2 award IK2 RX002938). Study results will be disseminated at or before the project's end date in March 2028.

CONCLUSIONS

We will provide preliminary evidence of the safety, feasibility, and acceptability of a novel frontal pole iTBS treatment for mTBI, impulsivity, SI and SAs, and functional deficits.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05647044; https://clinicaltrials.gov/study/NCT05647044.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/58206.

Common and divergent neuroimaging features in major depression, posttraumatic stress disorder, and their comorbidity

Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) are common stress-related psychiatric disorders. Genetic and neurobiology research has supported the viewpoint that PTSD and MDD may possess common and disorder-specific underlying mechanisms. In this systematic review, we summarize evidence for the similarities and differences in brain functional and structural features of MDD, PTSD, and their comorbidity, as well as the effects of extensively used therapies in patients with comorbid PTSD and MDD (PTSD + MDD). These functional magnetic resonance imaging (MRI) studies highlight the (i) shared hypoactivation in the prefrontal cortex during cognitive and emotional processing in MDD and PTSD; (ii) higher activation in fear processing regions including amygdala, hippocampus, and insula in PTSD compared to MDD; and (iii) distinct functional deficits in brain regions involved in fear and reward processing in patients with PTSD + MDD relative to those with PTSD alone. These structural MRI studies suggested that PTSD and MDD share features of reduced volume in focal frontal areas. The treatment effects in patients with PTSD + MDD may correlate with the normalization trend of structural alterations. Neuroimaging predictors of repetitive transcranial magnetic stimulation response in patients with PTSD + MDD may differ from the mono-diagnostic groups. In summary, neuroimaging studies to date have provided limited information about the shared and disorder-specific features in MDD and PTSD. Further research is essential to pave the way for developing improved diagnostic markers and eventually targeted treatment approaches for the shared and distinct brain alterations presented in patients with MDD and PTSD.

Alterations of insular dynamic functional connectivity and psychological characteristics in unmedicated bipolar depression patients with a recent suicide attempt

BACKGROUND

Mounting evidence showed that insula contributed to the neurobiological mechanism of suicidal behaviors in bipolar disorder (BD). However, no studies have analyzed the dynamic functional connectivity (dFC) of insular Mubregions and its association with personality traits in BD with suicidal behaviors. Therefore, we investigated the alterations of dFC variability in insular subregions and personality characteristics in BD patients with a recent suicide attempt (SA).

METHODS

Thirty unmedicated BD patients with SA, 38 patients without SA (NSA) and 35 demographically matched healthy controls (HCs) were included. The sliding-window analysis was used to evaluate whole-brain dFC for each insular subregion seed. We assessed between-group differences of psychological characteristics on the Minnesota Multiphasic Personality Inventory-2. Finally, a multivariate regression model was adopted to predict the severity of suicidality.

RESULTS

Compared to NSA and HCs, the SA group exhibited decreased dFC variability values between the left dorsal anterior insula and the left anterior cerebellum. These dFC variability values could also be utilized to predict the severity of suicidality (r = 0.456, p = 0.031), while static functional connectivity values were not appropriate for this prediction. Besides, the SA group scored significantly higher on the schizophrenia clinical scales (p < 0.001) compared with the NSA group.

CONCLUSIONS

Our findings indicated that the dysfunction of insula-cerebellum connectivity may underlie the neural basis of SA in BD patients, and highlighted the dFC variability values could be considered a neuromarker for predictive models of the severity of suicidality. Moreover, the psychiatric features may increase the vulnerability of suicidal behavior.

Effects of repetitive transcranial magnetic stimulation and their underlying neural mechanisms evaluated with magnetic resonance imaging-based brain connectivity network analyses

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive brain modulation and rehabilitation technique used in patients with neuropsychiatric diseases. rTMS can structurally remodel or functionally induce activities of specific cortical regions and has developed to an important therapeutic method in such patients. Magnetic resonance imaging (MRI) provides brain data that can be used as an explanation tool for the neural mechanisms underlying rTMS effects; brain alterations related to different functions or structures may be reflected in changes in the interaction and influence of brain connections within intrinsic specific networks. In this review, we discuss the technical details of rTMS and the biological interpretation of brain networks identified with MRI analyses, comprehensively summarize the neurobiological effects in rTMS-modulated individuals, and elaborate on changes in the brain network in patients with various neuropsychiatric diseases receiving rehabilitation treatment with rTMS. We conclude that brain connectivity network analysis based on MRI can reflect alterations in functional and structural connectivity networks comprising adjacent and separated brain regions related to stimulation sites, thus reflecting the occurrence of intrinsic functional integration and neuroplasticity. Therefore, MRI is a valuable tool for understanding the neural mechanisms of rTMS and practically tailoring treatment plans for patients with neuropsychiatric diseases.

Aberrant dynamic functional connectivity in corticostriatal circuitry in depressed bipolar II disorder with recent suicide attempt

BACKGROUND

The underlying neurobiological mechanisms on suicidal behavior in bipolar disorder remain unclear. We aim to explore the mechanisms of suicide by detecting dynamic functional connectivity (dFC) of corticostriatal circuitry and cognition in depressed bipolar II disorder (BD II) with recent suicide attempt (SA).

METHODS

We analyzed resting-state functional magnetic resonance imaging (fMRI) data from 68 depressed patients with BD-II (30 with SA and 38 without SA) and 35 healthy controls (HCs). The whole-brain dFC variability of corticostriatal circuitry was calculated using a sliding-window analysis. Their correlations with cognitive dysfunction were further detected. Support vector machine (SVM) classification tested the potential of dFC to differentiate BD-II with SA from HCs.

RESULTS

Increased dFC variability between the right vCa and the right insula was found in SA compared to non-SA and HCs, and negatively correlated with speed of processing. Decreased dFC variability between the left dlPu and the right postcentral gyrus was found in non-SA compared to SA and HCs, and positively correlated with reasoning problem-solving. Both SA and non-SA exhibited decreased dFC variability between the right dCa and the left MTG, and between the right dlPu and the right calcarine when compared to HCs. SVM classification achieved an accuracy of 75.24 % and AUC of 0.835 to differentiate SA from non-SA, while combining the abnormal dFC features between SA and non-SA.

CONCLUSIONS

Aberrant dFC variability of corticostriatal circuitry may serve as potential neuromarker for SA in BD-II, which might help to discriminate suicidal BD-II patients from non-suicidal patients and HCs.

Therapeutic potential of brain stimulation techniques in the treatment of mental, psychiatric, and cognitive disorders

Treatment for brain diseases has been disappointing because available medications have failed to produce clinical response across all the patients. Many patients either do not respond or show partial and inconsistent effect, and even in patients who respond to the medications have high relapse rates. Brain stimulation has been seen as an alternative and effective remedy. As a result, brain stimulation has become one of the most valuable therapeutic tools for combating against brain diseases. In last decade, studies with the application of brain stimulation techniques not only have grown exponentially but also have expanded to wide range of brain disorders. Brain stimulation involves passing electric currents into the cortical and subcortical area brain cells with the use of noninvasive as well as invasive methods to amend brain functions. Over time, technological advancements have evolved into the development of precise devices; however, at present, most used noninvasive techniques are repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), whereas the most common invasive technique is deep brain stimulation (DBS). In the current review, we will provide an overview of the potential of noninvasive (rTMS and tDCS) and invasive (DBS) brain stimulation techniques focusing on the treatment of mental, psychiatric, and cognitive disorders.

Implications of Transcranial Magnetic Stimulation as a Treatment Modality for Tinnitus

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive, neuromodulating technique for brain hyperexcitability disorders. The objective of this paper is to discuss the mechanism of action of rTMS as well as to investigate the literature involving the application of rTMS in the treatment of tinnitus. The reviewed aspects of the protocols included baseline evaluation, the total number of sessions, frequency and the total number of stimuli, the location of treatment, and the outcome measures. Even with heterogeneous protocols, most studies utilized validated tinnitus questionnaires as baseline and outcome measures. Low frequency (1 Hz) stimulation throughout 10 consecutive sessions was the most widely used frequency and treatment duration; however, there was no consensus on the total number of stimuli necessary to achieve significant results. The auditory cortex (AC) was the most targeted location, with most studies supporting changes in neural activity with multi-site stimulation to areas in the frontal cortex (FC), particularly the dorsolateral prefrontal cortex (DLPFC). The overall efficacy across most of the reviewed trials reveals positive statistically significant results. Though rTMS has proven to impact neuroplasticity at the microscopic and clinical level, further studies are warranted to demonstrate and support the clinical use of rTMS in tinnitus treatment with a standardized protocol.

Repetitive transcranial magnetic stimulation and its role in suicidality - A systematic review

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) as a brain stimulation modality is approved for the treatment of resistant depression and its efficacy in depression is also well supported in several studies. However, its effect on suicidality is still unclear, unlike electroconvulsive therapy.

METHODOLOGY

This paper provides a systematic review of the literature published till June 2021. Studies that used rTMS as either monotherapy or adjunctive treatment in patients with suicidality, irrespective of their diagnosis, were included. The Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines was followed. A total of 20 studies (N = 1584) were included for the qualitative synthesis. The quality of studies was assessed using the Cochrane Risk of Bias tool for Randomised control trials (RCT) and the Newcastle-Ottawa Scale tool for Non-Randomised studies (NRS).

RESULTS

Of the 20 articles selected for qualitative synthesis, 11 were RCTs and 9 were NRS. The results are categorized in domains of type of the study, size of population, type of population, diagnosis, assessment scales, mode of rTMS, stimulus parameters, safety and efficacy.

CONCLUSIONS

The high frequency rTMS at left dorsolateral prefrontal cortex as an adjunct to antidepressant medication is promising in reducing suicidal behaviour in treatment resistant depression. However, role of TMS targeting other areas of stimulation in mitigating suicide risk in other disorders could not be established due to scarcity of such studies. The results should be interpreted cautiously as considerable risk of bias was present in the reviewed studies.