Efficacy of deep brain stimulation for treatment-resistant obsessive-compulsive disorder: systematic review and meta-analysis

Efficacy and safety of transcranial direct current stimulation (tDCS) in patients with obsessive-compulsive disorder (OCD): A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Transcranial direct current stimulation (tDCS) is gaining traction for treating obsessive-compulsive disorder (OCD), but its effectiveness and safety remain uncertain. A systematic review of randomized controlled trials (RCTs) will assess its clinical benefits for symptom reduction.

METHODS

Six databases-Scopus, PubMed, Web of Science, Cochrane, PsycINFO, and Cochrane Central-were searched to identify relevant studies. The included studies were RCTs that assessed the effects of tDCS on OCD symptoms, as well as its impact on anxiety and depression, while also evaluating adverse events (AEs). The risk of bias (ROB) was analyzed using the ROB-2 tool. A meta-analysis was performed utilizing Stata-17 software.

RESULTS

Immediately following treatment, the analysis revealed that tDCS significantly reduced the Y-BOCS score (SMD = -0.56 [-0.87, -0.26]), anxiety scores (SMD = -1.11 [-1.85, -0.37]), and depression scores (SMD = -1.57 [-2.64, -0.50]), while increasing CGI-S scores (SMD = 0.40 [0.08, 0.72]) in OCD patients compared to the sham group. During the follow-up period (1-2 months post-treatment), tDCS continued to decrease the Y-BOCS score (SMD = -0.69 [-1.22, -0.17]), anxiety scores (SMD = -1.13 [-3.05, -0.78]), and depression scores (SMD = -2.02 [-3.00, -1.04]), but showed no effect on CGI-S scores when compared to the sham group. Additionally, the analysis indicated no significant differences in AEs between active tDCS and the sham group (OR: 1.20 [0.86, 1.68]).

CONCLUSIONS

This review suggests that tDCS may effectively alleviate OCD symptoms, along with related depression and anxiety, both acute and at follow-up, while causing minimal AEs.

Efficacy of Adjunctive Deep Transcranial Magnetic Stimulation in Obsessive-Compulsive Disorder: A Randomized Sham-Controlled Study

OBJECTIVES

Obsessive-compulsive disorder is one of the most common neuropsychiatric disorders with a higher lifetime prevalence than schizophrenia, often showing inadequate response to pharmacological and psychotherapeutic treatments. This study aimed to examine the efficacy of adjunctive deep transcranial magnetic stimulation (dTMS) in a randomized, sham-controlled set-up, addressing inadequate response to standard treatments.

METHODS

Forty-nine obsessive-compulsive disorder patients were randomly allocated to receive either high-frequency dTMS (20 Hz) or sham stimulation and received 10 sessions of treatment using the H7 coil to target the dorsal anterior cingulate cortex and the medial prefrontal cortex over a period of 2 weeks. Change in Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) scores was the primary outcome measure. Secondary efficacy measures were changes in Hamilton Anxiety Rating Scale and Hamilton Depression Rating Scale scores and response rates as measured by Y-BOCS.

RESULTS

The active dTMS group demonstrated a significant reduction in Y-BOCS scores compared with sham (-10.4 vs -2.6 points; P < 0.001), with an effect size of 1.39. Full response rates were 75% in the active group versus 5% in the sham group (P < 0.001). Anxiety and depressive symptoms also improved significantly in the active group (Hamilton Anxiety Rating Scale: -9.1 vs -2.4 points, P < 0.001; Hamilton Depression Rating Scale: -5.9 vs -1.8 points, P < 0.001).

CONCLUSION

Our study demonstrated that dTMS targeting the dorsal anterior cingulate cortex and medial prefrontal cortex significantly improved obsessive-compulsive, anxiety, and depressive symptoms, with faster response rates and fewer sessions compared with previous trials, suggesting that dTMS may serve as an effective early intervention for a wider range of obsessive-compulsive disorder patients.

Stereo-encephalography-guided multi-lead deep brain stimulation for treatment-refractory obsessive compulsive disorder - study design and individualized surgical targeting approach

Introduction

Treatment-refractory obsessive-compulsive disorder (trOCD) is a complex brain network disorder that remains partially understood and may require personalized treatment strategies due to disease heterogeneity. While stereo-electroencephalography (sEEG) is standard of care for surgical epilepsy workups, its use in refractory neuropsychiatric disorders remains investigational. A multi-site, multi-stage, double-blinded, randomized crossover clinical trial is currently underway, using sEEG to guide selection of multi-nodal targets for subsequent deep brain stimulation (DBS) in the treatment of trOCD.

Objectives

To describe the study design of this ongoing clinical trial, with an emphasis on personalized surgical targeting strategies that ensure both the feasibility and precision of sEEG electrode placement, and enable adequate sampling of relevant targets in trOCD for network evaluation and modulation.

Methods

Adult patients with severe trOCD (Yale-Brown Obsessive Compulsive Scale ≥ 28) who meet eligibility criteria will be enrolled in this study. The clinical trial ( NCT05623306 ) involves three stages. In stage 1, up to 20 sEEG electrodes will be implanted in cortical and subcortical regions implicated in trOCD. Individualized probabilistic-tractography-guided target refinement will be performed for surgical planning. To ensure surgical feasibility of non-conventional surgical trajectories, patient-specific three-dimensional (3D) printed head models may be used for surgical rehearsal. Continuous and synchronous audiovisual and intracranial electroencephalographic (iEEG) recordings will be performed in the psychiatric monitoring unit. Participants undergo psychologist-led symptom provocations, brain stimulation evoked potential mapping, acute stimulation testing and cognitive tasks over a 12-day inpatient evaluation. In stage 2, up to four permanent DBS electrodes will be implanted followed by stimulation optimization for up to 52 weeks. Stage 3 involves a randomized, double-blinded cross-over phase.

Expected Outcomes

Safety, feasibility and preliminary efficacy will be assessed in this ongoing study. Primary safety endpoints include the number and type of serious adverse events. Feasibility endpoints include percentage of patients in whom OCD-relevant network or stimulation target can be identified. Treatment response will be determined by change in Y-BOCS II score between active and sham stimulation conditions. We anticipate that sEEG to guide selection of multi-nodal targets for DBS will be safe, feasible and result in clinically meaningful improvements in symptom severity and functional impairment in trOCD.

Discussion

We present the clinical protocol of sEEG-guided investigation of brain networks involved in trOCD and describe our tractography-guided surgical targeting strategy designed to optimize individualized network engagement and neuromodulation.

Deep Brain Stimulation Response Circuits in Obsessive-Compulsive Disorder

In the field of deep brain stimulation (DBS), 2 major themes are currently making significant progress. The first of these is the framework of connectomic DBS, in which circuits that are associated with improvements of specific symptoms are described and targeted to improve and potentially personalize treatment. The second theme is related to the concept of brain sensing and adaptive DBS, which are aimed at identifying neural biomarkers that may guide stimulation in a closed-loop fashion. In DBS for obsessive-compulsive disorder (OCD), substantial progress has been made on both ends over the last 5 years. Together, the results have begun to draw a picture of exactly which circuit is associated with treatment response and how it may be affected by dysfunctional brain activity that may be attenuated using DBS. This knowledge, if further refined and validated, will define where, when, and how to stimulate which patients with OCD. We review the key studies from recent years with the aim of aggregating and condensing findings along both spatial and temporal domains. The result is a concept that anatomically defines a circuit that is likely dysfunctional in patients with typical OCD phenotypes and that may be adaptively targeted using DBS to maximally improve symptoms.

Pitfalls and practical suggestions for using local field potential recordings in DBS clinical practice and research

Objective. Local field potential (LFP) recordings using chronically implanted sensing-enabled stimulators are a powerful tool for indexing symptom presence and severity in neurological and neuropsychiatric disorders, and for enhancing our neurophysiological understanding of brain processes. LFPs have gained interest as input signals for closed-loop deep brain stimulation (DBS) and can be used to inform DBS parameter selection. LFP recordings using chronically implanted sensing-enabled stimulators have various implementational challenges.Approach. Here we describe our collective experience using BrainSense (Medtronic®) for clinical and research work. We aim to provide insightful tips and practical advice to empower readers with the knowledge needed to navigate the intricacies of the device and make the most out of its features.Main results. The central issues that apply to several BrainSense features encompass restricted compatibility of stimulation configuration with sensing, differences in electrophysiological signal properties between 'stimulation OFF' and 'stimulation ON at 0.0 mA', and challenges associated with the internal clock of the neurostimulator. In addition, since recordings are obtained from bipolar and not monopolar channels, spatial certainty regarding the distribution of LFPs around the DBS electrode is limited. Several options exist to synchronize LFP time series with external data streams, but standardization and generalization are lacking. The use of at-home chronic LFP recording is limited by a low temporal and spectral resolution. Regarding at-home LFP snapshots, LFP time series are not stored, parts of the power spectrum are censored when stimulating at high or low frequencies, and the stimulation amplitude is not readily available.Significance. We discussed practical applications, implementation, system limitations, and pitfalls with the aim that sensing can be better applied for clinical practice and research.

Deep brain stimulation - A primer for psychiatrists

Deep Brain Stimulation is a form of neurostimulation where electrical stimulation is delivered via intracranial electrodes over specific subcortical targets. It has been increasingly used as an alternative to ablative procedures for psychiatric disorders refractory to standard treatments. This review describes the common psychiatric indications for DBS, the current evidence base, putative mechanisms, and future directions.

Past and Present Role of Neurosurgical Interventions in the Management of Psychiatric Disorders: A Literature Review on the Evolution of Psychosurgery

Despite advancements in psychiatric treatments, many patients with treatment-resistant disorders are turning to neurosurgical interventions. These include neuromodulation-based surgeries such as deep brain stimulation (DBS) and ablative surgeries such as cingulotomy, offering relief for severe conditions such as post-traumatic stress disorder (PTSD), depression, schizophrenia, obsessive-compulsive disorder (OCD), anxiety, and substance use disorder. While "psychosurgery" has sparked debate due to concerns about patient well-being, recent studies indicate promising symptom improvement rates across various psychiatric conditions while also demonstrating overall safety. Neuromodulation techniques, such as DBS, transcranial magnetic stimulation (TMS), and electroconvulsive therapy (ECT), have evolved in regard to their sensitivity and their ability to target specific brain regions to alleviate psychiatric symptoms. Despite their benefits, these therapies have been shown to elicit side effects such as memory loss and seizures in patients, which has sparked controversy in the use of this technology across clinicians and patients. Ablative therapies, on the other hand, are concerning for being overly invasive in their approach toward psychiatric care. Despite the stigma associated with these neurosurgical interventions for psychiatric care, these procedures often remain a last resort for many patients, highlighting the need for continued research to improve these treatments and expand options for those in need. In this narrative review, we examine the current literature to elicit an understanding of neurosurgical history in regard to psychiatric disorder treatment and its implications for clinical practice.

Sustained improvement of obsessive-compulsive symptoms following interruption of deep brain stimulation

A 59-year-old male with severe treatment-resistant OCD achieved sustained symptom improvement after discontinuing deep brain stimulation (DBS) for over four years. Despite partial relief with ventral capsule/ventral striatum (VC/VS) DBS, complications led to device removal in 2018. Remarkably, the patient remained largely symptom-free, suggesting neuroplasticity changes in dysfunctional neurocircuits. This rare case highlights DBS's role in psychiatry, emphasizing the need for tailored surgical strategies and long-term follow-ups to optimize outcomes and understand DBS mechanisms.

Deep Brain Stimulation for Childhood Treatment-Resistant Obsessive-Compulsive Disorder: Mental Health Clinician Views on Candidacy Factors

INTRODUCTION

Deep brain stimulation (DBS) is approved under a humanitarian device exemption to manage treatment-resistant obsessive-compulsive disorder (TR-OCD) in adults. It is possible that DBS may be trialed or used clinically off-label in children and adolescents with TR-OCD in the future. DBS is already used to manage treatment-resistant childhood dystonia. Evidence suggests it is a safe and effective intervention for certain types of dystonia. Important questions remain unanswered about the use of DBS in children and adolescents with TR-OCD, including whether mental health clinicians would refer pediatric patients for DBS, and who would be a good candidate for DBS.

OBJECTIVES

To explore mental health clinicians' views on what clinical and psychosocial factors they would consider when determining which children with OCD would be good DBS candidates.

MATERIALS AND METHODS

In depth, semi-structured interviews were conducted with n = 25 mental health clinicians who treat pediatric patients with OCD. The interviews were transcribed, coded, and analyzed using thematic content analysis. Three questions focused on key, clinical, and psychosocial factors for assessing candidacy were analyzed to explore respondent views on candidacy factors. Our analysis details nine overarching themes expressed by clinicians, namely the patient's previous OCD treatment, OCD severity, motivation to commit to treatment, presence of comorbid conditions, family environment, education on DBS, quality of life, accessibility to treatment, and patient age and maturity.

CONCLUSIONS

Clinicians generally saw considering DBS treatment in youth as a last resort and only for very specific cases. DBS referral was predominantly viewed as acceptable for children with severe TR-OCD who have undertaken intensive, appropriate treatment without success, whose OCD has significantly reduced their quality of life, and who exhibit strong motivation to continue treatment given the right environment. Appropriate safeguards, eligibility criteria, and procedures should be discussed and identified before DBS for childhood TR-OCD becomes practice.

A Low-Intensity Transcranial Focused Ultrasound Parameter Exploration Study of the Ventral Capsule/Ventral Striatum

OBJECTIVES

Deep brain stimulation (DBS) of the ventral capsule/ventral striatum (VC/VS) is effective for treatment-resistant obsessive-compulsive disorder (OCD); however, DBS is associated with neurosurgical risks. Transcranial focused ultrasound (tFUS) is a newer form of noninvasive (ie, nonsurgical) stimulation that can modulate deeper regions, such as the VC/VS. tFUS parameters have just begun to be studied and have often not been compared in the same participants. We explored the effects of three VC/VS tFUS protocols and an entorhinal cortex (ErC) tFUS session on the VC/VS and cortico-striato-thalamo-cortical circuit (CSTC) in healthy individuals for later application to patients with OCD.

MATERIALS AND METHODS

Twelve individuals participated in a total of 48 sessions of tFUS in this exploratory multisite, within-subject parameter study. We collected resting-state, reward task, and arterial spin-labeled (ASL) magnetic resonance imaging scans before and after ErC tFUS and three VC/VS tFUS sessions with different pulse repetition frequencies (PRFs), pulse widths (PWs), and duty cycles (DCs).

RESULTS

VC/VS protocol A (PRF = 10 Hz, PW = 5 ms, 5% DC) was associated with increased putamen activation during a reward task (p = 0.003), and increased VC/VS resting-state functional connectivity (rsFC) with the anterior cingulate cortex (p = 0.022) and orbitofrontal cortex (p = 0.004). VC/VS protocol C (PRF = 125 Hz, PW = 4 ms, 50% DC) was associated with decreased VC/VS rsFC with the putamen (p = 0.017), and increased VC/VS rsFC with the globus pallidus (p = 0.008). VC/VS protocol B (PRF = 125 Hz, PW = 0.4 ms, 5% DC) was not associated with changes in task-related CSTC activation or rsFC. None of the protocols affected CSTC ASL perfusion.

CONCLUSIONS

This study began to explore the multidimensional parameter space of an emerging form of noninvasive brain stimulation, tFUS. Our preliminary findings in a small sample suggest that VC/VS tFUS should continue to be investigated for future noninvasive treatment of OCD.

A Reproducible Pipeline for Parcellation of the Anterior Limb of the Internal Capsule

BACKGROUND

The anterior limb of the internal capsule (ALIC) is a white matter structure that connects the prefrontal cortex (PFC) to the brainstem, thalamus, and subthalamic nucleus. It is a target for deep brain stimulation for obsessive-compulsive disorder. There is strong interest in improving deep brain stimulation targeting by using diffusion tractography to reconstruct and target specific ALIC fiber pathways, but this methodology is susceptible to errors and lacks validation. To address these limitations, we developed a novel diffusion tractography pipeline that generates reliable and biologically validated ALIC white matter reconstructions.

METHODS

Following algorithm development and refinement, we analyzed 43 control participants, each with 2 sets of 3T magnetic resonance imaging data and a subset of 5 control participants with 7T data from the Human Connectome Project. We generated 22 segmented ALIC fiber bundles (11 per hemisphere) based on PFC regions of interest, and we analyzed the relationships among bundles.

RESULTS

We successfully reproduced the topographies established by previous anatomical work using images acquired at both 3T and 7T. Quantitative assessment demonstrated significantly smaller intraparticipant variability than interparticipant variability for both test and retest groups across all but one PFC region. We examined the overlap between fibers from different PFC regions and a response tract for obsessive-compulsive disorder deep brain stimulation, and we reconstructed the PFC hyperdirect pathway using a modified version of our pipeline.

CONCLUSIONS

Our diffusion magnetic resonance imaging algorithm reliably generates biologically validated ALIC white matter reconstructions, thereby allowing for more precise modeling of fibers for neuromodulation therapies.

Genomics of severe and treatment-resistant obsessive-compulsive disorder treated with deep brain stimulation: A preliminary investigation

Individuals with severe and treatment-resistant obsessive-compulsive disorder (trOCD) represent a small but severely disabled group of patients. Since trOCD cases eligible for deep brain stimulation (DBS) probably comprise the most severe end of the OCD spectrum, we hypothesize that they may be more likely to have a strong genetic contribution to their disorder. Therefore, while the worldwide population of DBS-treated cases may be small (~300), screening these individuals with modern genomic methods may accelerate gene discovery in OCD. As such, we have begun to collect DNA from trOCD cases who qualify for DBS, and here we report results from whole exome sequencing and microarray genotyping of our first five cases. All participants had previously received DBS in the bed nucleus of stria terminalis (BNST), with two patients responding to the surgery and one showing a partial response. Our analyses focused on gene-disruptive rare variants (GDRVs; rare, predicted-deleterious single-nucleotide variants or copy number variants overlapping protein-coding genes). Three of the five cases carried a GDRV, including a missense variant in the ion transporter domain of KCNB1, a deletion at 15q11.2, and a duplication at 15q26.1. The KCNB1 variant (hg19 chr20-47991077-C-T, NM_004975.3:c.1020G>A, p.Met340Ile) causes substitution of methionine for isoleucine in the trans-membrane region of neuronal potassium voltage-gated ion channel KV2.1. This KCNB1 substitution (Met340Ile) is located in a highly constrained region of the protein where other rare missense variants have previously been associated with neurodevelopmental disorders. The patient carrying the Met340Ile variant responded to DBS, which suggests that genetic factors could potentially be predictors of treatment response in DBS for OCD. In sum, we have established a protocol for recruiting and genomically characterizing trOCD cases. Preliminary results suggest that this will be an informative strategy for finding risk genes in OCD.

Efficacy of Deep Brain Stimulation for Treatment-Resistant Depression: Systematic Review and Meta-Analysis

BACKGROUND

Treatment-resistant depression affects about 30% of individuals with major depressive disorder. Deep brain stimulation is an investigational intervention for treatment-resistant depression with varied results. We undertook this meta-analysis to synthesize outcome data across trial designs, anatomical targets, and institutions to better establish efficacy and side-effect profiles.

METHODS

We conducted a systematic PubMed review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Seven randomized controlled trials (n = 198) and 8 open-label trials (n = 77) were included spanning 2009 to 2020. Outcome measures included Hamilton Depression Rating Scale or Montgomery-Åsberg Depression Rating Scale scores, as well as response and remission rates over time. Outcomes were tracked at the last follow-up and quantified as a time course using model-based network meta-analysis. Linear mixed models were fit to individual patient data to identify covariates.

RESULTS

Deep brain stimulation achieved 47% improvement in long-term depression scale scores, with an estimated time to reach 50% improvement of around 23 months. There were no significant subgroup effects of stimulation target, time of last follow-up, sex, age of disease onset, or duration of disease, but open-label trials showed significantly greater treatment effects than randomized controlled trials. Long-term (12-60 month) response and remission rates were 48% and 35%, respectively. The time course of improvement with active stimulation could not be adequately distinguished from that with sham stimulation, when available.

CONCLUSIONS

Deep brain stimulation produces significant chronic improvement in symptoms of treatment-resistant depression. However, the limited sham-controlled data do not demonstrate significant improvement over placebo. Future advancements in stimulation optimization and careful blinding and placebo schemes are important next steps for this therapy.

The persistent value of lesions in psychiatric neurosurgery

Neurosurgery for intractable psychiatric conditions has seen a resurgence with the increasing use of deep brain stimulation (DBS). Although DBS promises reversible neuromodulation and has become more popular than older lesioning methods, lesioning might still be preferred in specific cases. Here, we review the evidence for DBS and lesions in the treatment of intractable neuropsychiatric conditions and consider the factors that favour the continued use of lesioning procedures in appropriately selected cases. Broadly, systemic factors including comparative effectiveness, cost, and ethical arguments support an ongoing role for lesioning. Such a role is also supported by practical considerations including patient experiences of this type of therapy, the relative intensity of follow-up care, access to sparse or specialised follow-up care, and relative infection risk. Overall, we argue that neurosurgical lesion procedures remain an important alternative to DBS and their continued availability is necessary to fulfil the imperatives of mental health parity and enhance access to effective mental health treatments. Nonetheless, the efficacy of DBS and recent advances in closed-loop stimulation and remote programming might provide solutions to some of the challenges associated with wider use of electrical neuromodulation. Concerns about the scarcity of high-level evidence for the efficacy of lesioning procedures as well as the potential irreversible adverse effects of lesioning remain to be addressed.

Assessing the Pharmacotherapy and Clinical Outcomes After Deep Brain Stimulation for Treatment-Refractory Obsessive-Compulsive Disorder: A Case-Cohort Study

Background: In the search for effective treatments for refractive obsessive-compulsive disorder (OCD), deep brain stimulation (DBS) serves as an alternative option for those with minimal response to pharmacotherapy. The rarity of reports regarding DBS use for OCD is attributed to the invasive nature of the procedure: placement of electrodes within targeted areas of the brain to provide neuromodulation. This treatment of last resort may decrease functional impairment and pharmacologic complications for a debilitating mental illness. This study compares the pharmacotherapy utilization and treatment outcomes of five treatment-refractory OCD patients after the placement of DBS with those of a matched cohort. Methods: This retrospective, single-center, case-cohort study reviewed the electronic medical records of five subjects treated with DBS for treatment-refractory OCD and compared them to a similar treatment-refractory cohort whose OCD was treated without the use of DBS. Control subjects were matched by age, sex, years since diagnosis, number of previous medication class trials, and additional clinical factors. Inclusion criteria were defined as those that are at least eighteen years of age, assigned a primary diagnosis of OCD per the ICD-10 classification, and received DBS treatment for refractory OCD. Exclusion criteria included comorbid psychotic disorders, unstable neurological or coagulation disorder(s), and/or an eating disorder diagnosis. The primary endpoint was the change in the number of psychotropic medications two years after implantation for the DBS cohort and two years after psychiatric decompensation for the comparator cohort. Secondary endpoints included: Y-BOCS (the Yale-Brown Obsessive-Compulsive Scale) changes over time, duration quantity of psychotropic medication classes prescribed, and additional symptomology scale changes. Results: Patients receiving DBS were more likely to be on fewer medications and trialed fewer medications after treatment. One out of the five patients was found to be a responder in Y-BOCS scoring after DBS treatment. A reduction in anxiety and depression symptoms was also seen in the HAM-A and HAM-D scales for those that received DBS. Conclusions: A reduction in psychiatric medications trialed during therapy was observed, as well as varying reductions in OCD, anxiety, and depression symptomology following DBS. Results from this study indicate that DBS implantation may contribute to a reduction in polypharmacy while displaying DBS's potential impact on comorbid anxiety and depression symptoms. Given that the small sample size limits generalizability, additional prospective, randomized trials comparing the efficacy of DBS for OCD-specific symptomology and its overall impact on pharmacotherapy are needed in order to further establish the role of DBS as an accepted treatment option for OCD.

The future of transcranial ultrasound as a precision brain interface

Our understanding of brain circuit operations and disorders has rapidly outpaced our ability to intervene and restore them. Developing technologies that can precisely interface with any brain region and circuit may combine diagnostics with therapeutic intervention, expediting personalised brain medicine. Transcranial ultrasound stimulation (TUS) is a promising noninvasive solution to this challenge, offering focal precision and scalability. By exploiting the biomechanics of pressure waves on brain tissue, TUS enables multi-site targeted neuromodulation across distributed circuits in the cortex and deeper areas alike. In this Essay, we explore the emergent evidence that TUS can functionally test and modify dysfunctional regions, effectively serving as a search and rescue tool for the brain. We define the challenges and opportunities faced by TUS as it moves towards greater target precision and integration with advanced brain monitoring and interventional technology. Finally, we propose a roadmap for the evolution of TUS as it progresses from a research tool to a clinically validated therapeutic for brain disorders.

Multimodal Prediction of Obsessive-Compulsive Disorder and Comorbid Depression Severity and Energy Delivered by Deep Brain Electrodes

To develop reliable, valid, and efficient measures of obsessive-compulsive disorder (OCD) severity, comorbid depression severity, and total electrical energy delivered (TEED) by deep brain stimulation (DBS), we trained and compared random forests regression models in a clinical trial of participants receiving DBS for refractory OCD. Six participants were recorded during open-ended interviews at pre- and post-surgery baselines and then at 3-month intervals following DBS activation. Ground-truth severity was assessed by clinical interview and self-report. Visual and auditory modalities included facial action units, head and facial landmarks, speech behavior and content, and voice acoustics. Mixed-effects random forest regression with Shapley feature reduction strongly predicted severity of OCD, comorbid depression, and total electrical energy delivered by the DBS electrodes (intraclass correlation, ICC, = 0.83, 0.87, and 0.81, respectively. When random effects were omitted from the regression, predictive power decreased to moderate for severity of OCD and comorbid depression and remained comparable for total electrical energy delivered (ICC = 0.60, 0.68, and 0.83, respectively). Multimodal measures of behavior outperformed ones from single modalities. Feature selection achieved large decreases in features and corresponding increases in prediction. The approach could contribute to closed-loop DBS that would automatically titrate DBS based on affect measures.

Disruption of neural periodicity predicts clinical response after deep brain stimulation for obsessive-compulsive disorder

Recent advances in surgical neuromodulation have enabled chronic and continuous intracranial monitoring during everyday life. We used this opportunity to identify neural predictors of clinical state in 12 individuals with treatment-resistant obsessive-compulsive disorder (OCD) receiving deep brain stimulation (DBS) therapy ( NCT05915741 ). We developed our neurobehavioral models based on continuous neural recordings in the region of the ventral striatum in an initial cohort of five patients and tested and validated them in a held-out cohort of seven additional patients. Before DBS activation, in the most symptomatic state, theta/alpha (9 Hz) power evidenced a prominent circadian pattern and a high degree of predictability. In patients with persistent symptoms (non-responders), predictability of the neural data remained consistently high. On the other hand, in patients who improved symptomatically (responders), predictability of the neural data was significantly diminished. This neural feature accurately classified clinical status even in patients with limited duration recordings, indicating generalizability that could facilitate therapeutic decision-making.

Agomelatine efficacy in treatment resistant obsessive-compulsive disorder: A randomized controlled trial

BACKGROUND

Obsessive-compulsive disorder (OCD) is a prevalent and burdensome mental health condition, often resistant to conventional treatments. Agomelatine (Valdoxan), a compound acting on serotonin and melatonin systems, has shown promise in treating those with treatment-resistant OCD based on anecdotal reports and case studies.

METHODS

A randomized, double-blind controlled trial was conducted with 60 patients diagnosed with treatment-resistant OCD. Participants were randomized into an intervention group (receiving agomelatine 50 mg/day) and a control group (receiving placebo). OCD symptoms were assessed using the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) over a 12-week period.

RESULTS

There were no significant differences in age, gender, or baseline Y-BOCS scores between intervention and control groups. Agomelatine did not demonstrate a significant improvement in OCD symptoms compared to placebo. Adverse events were comparable between groups, and liver enzyme levels remained within the normal range.

CONCLUSION

This study, while not confirming superior efficacy compared to placebo, underscores the need for continued investigation into agomelatine's potential for treating specific subgroups of OCD patients, underscoring the need for more comprehensive and well-controlled trials in the future.

Dual Treatment of Refractory Focal Epilepsy and Obsessive-Compulsive Disorder With Intracranial Responsive Neurostimulation

Purpose of the Review

Intracranial neurostimulation is a well-established treatment of neurologic conditions such as drug-resistant epilepsy (DRE) and movement disorders, and there is emerging evidence for using deep brain stimulation to treat obsessive-compulsive disorder (OCD) and depression. Nearly all published reports of intracranial neurostimulation have focused on implanting a single device to treat a single condition. The purpose of this review was to educate neurology clinicians on the background literature informing dual treatment of 2 comorbid neuropsychiatric conditions epilepsy and OCD, discuss ethical and logistical challenges to dual neuropsychiatric treatment with a single device, and demonstrate the promise and pitfalls of this approach through discussion of the first-in-human closed-looped responsive neurostimulator (RNS) implanted to treat both DRE (on-label) and OCD (off-label).

Recent Findings

We report the first implantation of an intracranial closed-loop neurostimulation device (the RNS system) with the primary goal of treating DRE and a secondary exploratory goal of managing treatment-refractory OCD. The RNS system detects electrophysiologic activity and delivers electrical stimulation through 1 or 2 electrodes implanted into a patient's seizure-onset zones (SOZs). In this case report, we describe a patient with treatment-refractory epilepsy and OCD where the first lead was implanted in the right superior temporal gyrus to target the most active SOZ based on stereotactic EEG (sEEG) recordings and semiology. The second lead was implanted to target the right anterior peri-insular region (a secondary SOZ on sEEG) with the distal-most contacts in the right nucleus accumbens, a putative target for OCD neurostimulation treatment. The RNS system was programmed to detect and record the unique electrophysiologic signature of both the patient's seizures and compulsions and then deliver tailored electrical pulses to disrupt the pathologic circuitry.

Summary

Dual treatment of refractory focal epilepsy and OCD with an intracranial closed-loop neurostimulation device is feasible, safe, and potentially effective. However, there are logistical challenges and ethical considerations to this novel approach to treatment, which require complex care coordination by a large multidisciplinary team.

Deep Brain Stimulation for Obsessive-Compulsive Disorder: Optimal Stimulation Sites

BACKGROUND

Deep brain stimulation (DBS) is a promising treatment option for treatment-refractory obsessive-compulsive disorder (OCD). Several stimulation targets have been used, mostly in and around the anterior limb of the internal capsule and ventral striatum. However, the precise target within this region remains a matter of debate.

METHODS

Here, we retrospectively studied a multicenter cohort of 82 patients with OCD who underwent DBS of the ventral capsule/ventral striatum and mapped optimal stimulation sites in this region.

RESULTS

DBS sweet-spot mapping performed on a discovery set of 58 patients revealed 2 optimal stimulation sites associated with improvements on the Yale-Brown Obsessive Compulsive Scale, one in the anterior limb of the internal capsule that overlapped with a previously identified OCD-DBS response tract and one in the region of the inferior thalamic peduncle and bed nucleus of the stria terminalis. Critically, the nucleus accumbens proper and anterior commissure were associated with beneficial but suboptimal clinical improvements. Moreover, overlap with the resulting sweet- and sour-spots significantly estimated variance in outcomes in an independent cohort of 22 patients from 2 additional DBS centers. Finally, beyond obsessive-compulsive symptoms, stimulation of the anterior site was associated with optimal outcomes for both depression and anxiety, while the posterior site was only associated with improvements in depression.

CONCLUSIONS

Our results suggest how to refine targeting of DBS in OCD and may be helpful in guiding DBS programming in existing patients.

Tractography-Based Modeling Explains Treatment Outcomes in Patients Undergoing Deep Brain Stimulation for Obsessive-Compulsive Disorder

BACKGROUND

Deep brain stimulation (DBS) is an established and expanding therapy for treatment-refractory obsessive-compulsive disorder. Previous work has suggested that a white matter circuit providing hyperdirect input from the dorsal cingulate and ventrolateral prefrontal regions to the subthalamic nucleus could be an effective neuromodulatory target.

METHODS

We tested this concept by attempting to retrospectively explain through predictive modeling the ranks of clinical improvement as measured by the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) in 10 patients with obsessive-compulsive disorder who underwent DBS to the ventral anterior limb of internal capsule with subsequent programming uninformed by the putative target tract.

RESULTS

Rank predictions were carried out using the tract model by a team that was completely uninvolved in DBS planning and programming. Predicted Y-BOCS improvement ranks significantly correlated with actual Y-BOCS improvement ranks at the 6-month follow-up (r = 0.75, p = .013). Predicted score improvements correlated with actual Y-BOCS score improvements (r = 0.72, p = .018).

CONCLUSIONS

Here, we provide data in a first-of-its-kind report suggesting that normative tractography-based modeling can blindly predict treatment response in DBS for obsessive-compulsive disorder.

Pediatric Treatment-Resistant Obsessive Compulsive Disorder: Treatment Options and Challenges

Pediatric obsessive-compulsive disorder (OCD) is a chronic, potentially debilitating psychiatric condition. Although effective treatments exist, at least 10% of youth do not achieve remission despite receiving first-line treatments. This article reviews the extant, albeit limited, evidence supporting treatment approaches for youth with treatment-resistant OCD. A literature search for articles addressing pediatric treatment-resistant OCD was conducted through April 11, 2024. These results were augmented by searching for treatment-resistant OCD in adults; treatment strategies discovered for the adult population were then searched in the context of children and adolescents. In general, intensive treatment programs and antipsychotic augmentation of an antidepressant had the most substantial and consistent evidence base for treatment-resistant youth with OCD, although studies were limited and of relatively poor methodological quality (i.e., open trials, naturalistic studies). Several pharmacological approaches (clomipramine, antipsychotics [e.g., aripiprazole, risperidone], riluzole, ketamine, D-cycloserine, memantine, topiramate, N-acetylcysteine, ondansetron), largely based on supporting data among adults, have received varying levels of investigation and support. There is nascent support for how to treat pediatric treatment-resistant OCD. Future treatment studies need to consider how to manage the significant minority of youth who fail to benefit from first-line treatment approaches.

Obsessive-Compulsive Disorder in Children and Adolescents

Obsessive-compulsive disorder (OCD) in children and adolescents is a neurobehavioral condition that can lead to functional impairment in multiple domains and decreased quality of life. We review the clinical presentation, diagnostic considerations, and common comorbidities of pediatric OCD. An overview of the biological and psychological models of OCD is provided along with a discussion of developmental considerations in youth. We also describe evidence-based treatments for OCD in childhood and adolescence, including cognitive behavioral therapy (CBT) with exposure and response prevention (ERP) and pharmacotherapy. Finally, research evaluating the delivery of CBT in different formats and modalities is discussed, and we conclude with suggestions for future research directions.

[Treatment-resistant obsessive-compulsive disorders]

BACKGROUND

Obsessive-compulsive disorders (OCD) are mainly treated with disorder-specific cognitive behavioral therapy using exposure and response management and/or selective serotonin reuptake inhibitors; however, a significant subgroup of patients does not sufficiently benefit from this approach.

OBJECTIVE

This article provides an overview of treatment-resistant OCD.

MATERIAL AND METHODS

In this narrative review the definition, causes, diagnostic and therapeutic approaches to treatment-resistant OCD are addressed.

RESULTS

Treatment resistance can be assumed in the absence of clinically relevant improvement under therapy, in the sense of a reduction of < 25% on the Yale-Brown obsessive-compulsive scale and a score of 4 (no change) on the clinical global impression-improvement scale. The number of unsuccessful treatment attempts required to establish treatment resistance is defined differently. Causative factors include misdiagnosis, a high severity, comorbid disorders, substance use, specific symptom constellations, organic causes, environmental factors, and aggravating factors in psychotherapy and pharmacotherapy. Suggestions for diagnostic and therapeutic approaches based on the German S3 guideline on OCD are presented.

CONCLUSION

For patients with treatment resistance to first-line therapy, useful diagnostic and therapeutic recommendations are available (psychotherapeutic, psychopharmacological and neurostimulation procedures).

Network analysis of depression, cognitive functions, and suicidal ideation in patients with diabetes: an epidemiological study in Iran

AIMS

The main aim of this study was to assess the prevalence of suicidal ideation and previous suicide attempts among Iranian patients diagnosed with Type-1 diabetes (T1D) and Type-2 diabetes (T2D). Additionally, the study sought to estimate the network structure of depressive symptoms and cognitive functions.

METHODS

1073 patients participated in the current study. We used Patient Health Questionnaire-9 (PHQ-9), Ask Suicide-Screening Questionnaire, diabetes-related factors, and a battery of cognitive functions tasks to estimate network structures. Also, suicidal ideations and suicide attempts prevalence have been estimated. Statistical analyses were performed using R-studio software, including mixed-graphical models (MGMs) for undirected effects and Directed Acyclic Graphs (DAGs) for directed effects.

RESULTS

The prevalence of suicidal ideation was 29.97% in T1D and 26.81% in T2D (p < 0.05). The history of suicide attempts was higher in T1D (10.78%) compared to T2D (8.36%) (p < 0.01). In the MRF networks for T1D, suicidal ideation was directly linked to 'feeling guilt (PHQ.6)', 'Suicide (PHQ.9)', HbA1c, and FBS, while the Inhibition node was directly related to suicidal ideation. The DAGs suggested connections between 'depression', HbA1c, and 'inhibition' with suicidal ideation, along with a link between the current family history of suicide attempts and the patient's history of suicide attempts. For T2D, the MRF networks indicated direct links between suicidal ideation and 'anhedonia (PHQ.1)', 'suicide (PHQ.9)', age, being female, and BMI, with inhibition also being directly related to suicidal ideation. The DAGs revealed connections between 'depression', age, and 'inhibition' with suicidal ideation, as well as links between being female or single/divorced and the patient's history of suicide attempts.

CONCLUSION

The findings suggest that suicide ideation is highly prevalent in patients with diabetes, and these symptoms should be carefully monitored in these patients.

Electrocardiographic approach strategies in patients with Parkinson disease treated with deep brain stimulation

Deep brain stimulation (DBS) is an interdisciplinary and reversible therapy that uses high-frequency electrical stimulation to correct aberrant neural pathways in motor and cognitive neurological disorders. However, the high frequency of the waves used in DBS can interfere with electrical recording devices (e.g., electrocardiogram, electroencephalogram, cardiac monitor), creating artifacts that hinder their interpretation. The compatibility of DBS with these devices varies and depends on factors such as the underlying disease and the configuration of the neurostimulator. In emergencies where obtaining an electrocardiogram is crucial, the need for more consensus on reducing electrical artifacts in patients with DBS becomes a significant challenge. Various strategies have been proposed to attenuate the artifact generated by DBS, such as changing the DBS configuration from monopolar to bipolar, temporarily deactivating DBS during electrocardiographic recording, applying frequency filters both lower and higher than those used by DBS, and using non-standard leads. However, the inexperience of medical personnel, variability in DBS models, or the lack of a controller at the time of approach limit the application of these strategies. Current evidence on their reproducibility and efficacy is limited. Due to the growing elderly population and the rising utilization of DBS, it is imperative to create electrocardiographic methods that are easily accessible and reproducible for general physicians and emergency services.

Neurosurgical neuromodulation therapy for psychiatric disorders

Psychiatric disorders are among the leading contributors to global disease burden and disability. A significant portion of patients with psychiatric disorders remain treatment-refractory to best available therapy. With insights from the neurocircuitry of psychiatric disorders and extensive experience of neuromodulation with deep brain stimulation (DBS) in movement disorders, DBS is increasingly being considered to modulate the neural network in psychiatric disorders. Currently, obsessive-compulsive disorder (OCD) is the only U.S. FDA (United States Food and Drug Administration) approved DBS indication for psychiatric disorders. Medically refractory depression, addiction, and other psychiatric disorders are being explored for DBS neuromodulation. Studies evaluating DBS for psychiatric disorders are promising but lack larger, controlled studies. This paper presents a brief review and the current state of DBS and other neurosurgical neuromodulation therapies for OCD and other psychiatric disorders. We also present a brief review of MR-guided Focused Ultrasound (MRgFUS), a novel form of neurosurgical neuromodulation, which can target deep subcortical structures similar to DBS, but in a noninvasive fashion. Early experiences of neurosurgical neuromodulation therapies, including MRgFUS neuromodulation are encouraging in psychiatric disorders; however, they remain investigational. Currently, DBS and VNS are the only FDA approved neurosurgical neuromodulation options in properly selected cases of OCD and depression, respectively.

Advancements in non-invasive microwave brain stimulation: A comprehensive survey

This survey provides a comprehensive insight into the world of non-invasive brain stimulation and focuses on the evolving landscape of deep brain stimulation through microwave research. Non-invasive brain stimulation techniques provide new prospects for comprehending and treating neurological disorders. We investigate the methods shaping the future of deep brain stimulation, emphasizing the role of microwave technology in this transformative journey. Specifically, we explore antenna structures and optimization strategies to enhance the efficiency of high-frequency microwave stimulation. These advancements can potentially revolutionize the field by providing a safer and more precise means of modulating neural activity. Furthermore, we address the challenges that researchers currently face in the realm of microwave brain stimulation. From safety concerns to methodological intricacies, this survey outlines the barriers that must be overcome to fully unlock the potential of this technology. This survey serves as a roadmap for advancing research in microwave brain stimulation, pointing out potential directions and innovations that promise to reshape the field.

Telemedicine in patients with obsessive-compulsive disorder after deep brain stimulation: a case series

Background

Patients suffering from refractory obsessive-compulsive disorder (OCD) who have undergone deep brain stimulation (DBS) surgery require repeated in-person programming visits. These sessions could be labor-intensive and may not always be feasible, particularly when in-person hospital visits are restricted. Telemedicine is emerging as a potential supplementary tool for post-operative care. However, its reliability and feasibility still require further validation due to the unconventional methods of interaction.

Methods

A study was conducted on three patients with refractory OCD who had undergone DBS. Most of their programming sessions were completed via a remote programming system. These patients were recruited and monitored for a year. Changes in their clinical symptoms were assessed using the Yale-Brown Obsessive-Compulsive Scale-Second Edition (Y-BOCS-II), the Hamilton Anxiety Scale-14 (HAMA), the Hamilton Depression Scale-17 (HAMD), and the Short Form 36 Health Survey Questionnaire (SF-36). The scores from these assessments were reported.

Results

At the last follow-up, two out of three patients were identified as responders, with their Y-BOCS-II scores improving by more than 35% (P1: 51%, P3: 42%). These patients also experienced some mood benefits. All patients observed a decrease in travel expenses during the study period. No severe adverse events were reported throughout the study.

Conclusion

The group of patients showed improvement in their OCD symptoms within a 1-year follow-up period after DBS surgery, without compromising safety or benefits. This suggests that telemedicine could be a valuable supplementary tool when in-person visits are limited.

Clinical outcomes of deep brain stimulation for obsessive-compulsive disorder: Insight as a predictor of symptom changes

AIM

Deep brain stimulation (DBS) is a safe and effective treatment option for people with refractory obsessive-compulsive disorder (OCD). Yet our understanding of predictors of response and prognostic factors remains rudimentary, and long-term comprehensive follow-ups are lacking. We aim to investigate the efficacy of DBS therapy for OCD patients, and predictors of clinical response.

METHODS

Eight OCD participants underwent DBS stimulation of the nucleus accumbens (NAc) in an open-label longitudinal trial, duration of follow-up varied between 9 months and 7 years. Post-operative care involved comprehensive fine tuning of stimulation parameters and adjunct multidisciplinary therapy.

RESULTS

Six participants achieved clinical response (35% improvement in obsessions and compulsions on the Yale Brown Obsessive Compulsive Scale (YBOCS)) within 6-9 weeks, response was maintained at last follow up. On average, the YBOCS improved by 45% at last follow up. Mixed linear modeling elucidated directionality of symptom changes: insight into symptoms strongly predicted (P = 0.008) changes in symptom severity during DBS therapy, likely driven by initial changes in depression and anxiety. Precise localization of DBS leads demonstrated that responders most often had their leads (and active contacts) placed dorsal compared to non-responders, relative to the Nac.

CONCLUSION

The clinical efficacy of DBS for OCD is demonstrated, and mediators of changes in symptoms are proposed. The symptom improvements within this cohort should be seen within the context of the adjunct psychological and biopsychosocial care that implemented a shared decision-making approach, with flexible iterative DBS programming. Further research should explore the utility of insight as a clinical correlate of response. The trial was prospectively registered with the ANZCTR (ACTRN12612001142820).

The promise and challenges of transcranial magnetic stimulation and deep brain stimulation as therapeutic options for obsessive-compulsive disorder

INTRODUCTION

Obsessive compulsive disorder (OCD) represents a complex and often difficult to treat disorder. Pharmacological and psychotherapeutic interventions are often associated with sub-optimal outcomes, and 40-60% of patients are resistant to first line therapies and thus left with few treatment options. OCD is underpinned by aberrant neurocircuitry within cortical, striatal, and thalamic brain networks. Considering the neurocircuitry impairments that underlie OCD symptomology, neurostimulation therapies provide an opportunity to modulate psychopathology in a personalized manner. Also, by probing pathological neural networks, enhanced understanding of disease states can be obtained.

AREAS COVERED

This perspective discusses the clinical efficacy of TMS and DBS therapies, treatment access options, and considerations and challenges in managing patients. Recent scientific progress is discussed, with a focus on neurocircuitry and biopsychosocial aspects. Translational recommendations and suggestions for future research are provided.

EXPERT OPINION

There is robust evidence to support TMS and DBS as an efficacious therapy for treatment resistant OCD patients supported by an excellent safety profile and favorable health economic data. Despite a great need for alternative therapies for chronic and severe OCD patients, resistance toward neurostimulation therapies from regulatory bodies and the psychiatric community remains. The authors contend for greater access to TMS and DBS for treatment resistant OCD patients at specialized sites with appropriate clinical resources, particularly considering adjunct and follow-up care. Also, connectome targeting has shown robust predictive ability of symptom improvements and holds potential in advancing personalized neurostimulation therapies.

Safety, feasibility, tolerability, and clinical effects of repeated psilocybin dosing combined with non-directive support in the treatment of obsessive-compulsive disorder: protocol for a randomized, waitlist-controlled trial with blinded ratings

Background

To date, few randomized controlled trials of psilocybin with non-directive support exist for obsessive-compulsive disorder (OCD). Results and participant feedback from an interim analysis of an ongoing single-dose trial (NCT03356483) converged on the possibility of administering a higher fixed dose and/or more doses of psilocybin in future trials for presumably greater benefits.

Objectives

This trial aims to evaluate the safety, feasibility, tolerability, and clinical effects of two doses of psilocybin paired with non-directive support in the treatment of OCD. This trial also seeks to examine whether two doses of psilocybin lead to greater OCD symptom reduction than a single dose, and to elucidate psychological mechanisms underlying the effects of psilocybin on OCD.

Design

A randomized (1:1), waitlist-controlled design with blinded ratings will be used to examine the effects of two doses of oral psilocybin paired with non-directive support vs. waitlist control on OCD symptoms. An adaptive dose selection strategy will be implemented (i.e., first dose: 25 mg; second dose: 25 or 30 mg).

Methods and analysis

This single-site trial will enroll 30 adult participants with treatment-refractory OCD. Aside from safety, feasibility, and tolerability metrics, primary outcomes include OCD symptoms assessed on the Yale-Brown Obsessive-Compulsive Scale - Second Edition (Y-BOCS-II). A blinded independent rater will assess primary outcomes at baseline and the primary endpoint at the end of the second dosing week. Participants will be followed up to 12 months post-second dosing. Participants randomized to waitlist will be rescreened after 7 weeks post-randomization, and begin their delayed treatment phase thereafter if still eligible.

Ethics

Written informed consent will be obtained from participants. The institutional review board has approved this trial (protocol v. 1.7; HIC #2000032623).

Discussion

This study seeks to advance our ability to treat refractory OCD, and catalyze future research seeking to optimize the process of psilocybin treatment for OCD through understanding relevant psychological mechanisms.Clinical trial registration: ClinicalTrials.gov, identifier NCT05370911.

Closed-loop neurostimulation for the treatment of psychiatric disorders

Despite increasing prevalence and huge personal and societal burden, psychiatric diseases still lack treatments which can control symptoms for a large fraction of patients. Increasing insight into the neurobiology underlying these diseases has demonstrated wide-ranging aberrant activity and functioning in multiple brain circuits and networks. Together with varied presentation and symptoms, this makes one-size-fits-all treatment a challenge. There has been a resurgence of interest in the use of neurostimulation as a treatment for psychiatric diseases. Initial studies using continuous open-loop stimulation, in which clinicians adjusted stimulation parameters during patient visits, showed promise but also mixed results. Given the periodic nature and fluctuations of symptoms often observed in psychiatric illnesses, the use of device-driven closed-loop stimulation may provide more effective therapy. The use of a biomarker, which is correlated with specific symptoms, to deliver stimulation only during symptomatic periods allows for the personalized therapy needed for such heterogeneous disorders. Here, we provide the reader with background motivating the use of closed-loop neurostimulation for the treatment of psychiatric disorders. We review foundational studies of open- and closed-loop neurostimulation for neuropsychiatric indications, focusing on deep brain stimulation, and discuss key considerations when designing and implementing closed-loop neurostimulation.

A Meta-analysis of Transcranial Magnetic Stimulation in Obsessive-Compulsive Disorder

BACKGROUND

Obsessive-compulsive disorder (OCD) is a debilitating illness with substantial morbidity. Although pharmacological and behavioral evidence-based treatments have shown efficacy, many patients remain unresponsive to this first-line care. Repetitive transcranial magnetic stimulation (rTMS) has shown significant promise for patients with treatment-refractory affective disorders. Therefore, we conducted a meta-analysis of randomized controlled trials to examine the therapeutic benefit of rTMS in patients with OCD and explore moderators of its treatment effects.

METHODS

PubMed (1997-Dec 31, 2022) and PsycINFO were searched for randomized sham-controlled trials of rTMS to treat OCD using the following terms: "obsessive-compulsive disorder," "transcranial magnetic stimulation," and "randomized controlled trial." Clinical characteristics and effect sizes were extracted from 25 randomized controlled trials (860 participants). A random effects model calculated the effect sizes for treatment efficacy and treatment response using the clinician-rated Yale-Brown Obsessive Compulsive Scale.

RESULTS

Across randomized controlled trials, rTMS exhibited a moderate therapeutic effect (g = 0.65) on OCD symptom severity and a 3-fold increased likelihood of treatment response (relative risk = 3.15) compared with sham conditions. Greater improvement in comorbid depression severity corresponded with greater treatment effects of rTMS on OCD symptom severity. In addition, longer rTMS sessions and fewer overall sessions predicted greater clinical improvement.

CONCLUSIONS

rTMS is moderately effective for reducing OCD symptom severity. It holds potential to serve as a therapeutic intervention, particularly for patients with OCD who have failed standard treatments and those with comorbid depression. Further research is needed to optimize rTMS protocols and evaluate the long-term efficacy of rTMS for OCD.

Changes in deep brain stimulation surgeries between 2019 and 2020: A national inpatient sample analysis

Background

Deep brain stimulation (DBS) surgery is a neurosurgical procedure that implants electrodes into the brain to treat a variety of neurological and psychiatric conditions. The COVID-19 pandemic resulted in significant disruptions in elective surgeries, but the impact on DBS surgeries remains largely unknown.

Methods

The National Inpatient Sample (NIS), an all-payors database of inpatient hospitalizations in the US, was queried for DBS implantation procedural codes in 2019 and 2020.

Results

There were a total of 7,625 hospitalizations (95% CI: 6,664 to 8,586) for the implantation of a DBS lead in the 2019 NIS, which reduced by 11.9% to 6,715 hospitalizations (95% CI: 5,872 to 7,558) in the 2020 NIS. Procedural numbers declined in March 2020, with a peak 92.7% decline in volume in April of 2020 relative to 2019. Case numbers for July through December 2020 were 96.1% of the 2019 volume. Overall patient demographics and primary discharge diagnoses for hospitalizations involving DBS implantation were similar in the two study years.

Conclusions

Surgical volume for DBS implantation reduced by 92.7% in April of 2020 relative to 2019, which is among the highest declines reported for any surgical procedure. While procedural volume increased in the second half of 2020, this did not make up for the reduction in procedures earlier in the year, highlighting the disruption in DBS surgeries in 2020.

Deep brain stimulation for treatment resistant obsessive compulsive disorder; an observational study with ten patients under real-life conditions

Introduction

Obsessive-compulsive disorder (OCD) affects 2-3% of the global population, causing distress in many functioning levels. Standard treatments only lead to a partial recovery, and about 10% of the patients remain treatment-resistant. Deep brain stimulation offers a treatment option for severe, therapy-refractory OCD, with a reported response of about 60%. We report a comprehensive clinical, demographic, and treatment data for patients who were treated with DBS in our institution.

Methods

We offered DBS to patients with severe chronic treatment resistant OCD. Severity was defined as marked impairment in functioning and treatment resistance was defined as non-response to adequate trials of medications and psychotherapy. Between 2020 and 2022, 11 patients were implanted bilaterally in the bed nucleus of stria terminalis (BNST). Patients were evaluated with YBOCS, MADRS, GAF, CGI, and WHOQOL-BREF. We performed the ratings at baseline (before surgery), after implantation before the start of the stimulation, after reaching satisfactory stimulation parameters, and at follow-up visits 3, 6, 9, and 12 months after optimized stimulation.

Results

One patient has retracted his consent to publish the results of his treatment, thus we are reporting the results of 10 patients (5 males, 5 females, mean age: 37 years). Out of our 10 patients, 6 have shown a clear response indicated by a YBOCS-reduction between 42 and 100 percent at last follow-up. One further patient experienced a subjectively dramatic effect on OCD symptoms, but opted afterwards to stop the stimulation. The other 3 patients showed a slight, non-significant improvement of YBOCS between 8.8 and 21.9%. The overall mean YBOCS decreased from 28.3 at baseline to 13.3 (53% reduction) at the last follow-up. The improvement of the OCD symptoms was also accompanied by an improvement of depressive symptoms, global functioning, and quality of life.

Conclusion

Our results suggest that BNST-DBS can be effective for treatment-resistant OCD patients, as indicated by a reduction in symptoms and an overall improvement in functioning. Despite the need for additional research to define the patients' selection criteria, the most appropriate anatomical target, and the most effective stimulation parameters, improved patient access for this therapy should be established.

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.

Spinal cord stimulation and deep brain stimulation for disorders of consciousness: a systematic review and individual patient data analysis of 608 cases

The application of spinal cord stimulation (SCS) and deep brain stimulation (DBS) for disorders of consciousness (DoC) has been increasingly reported. However, there is no sufficient evidence to determine how effective and safe SCS and DBS are for DoC owing to various methodological limitations. We conducted a systematic review to elucidate the safety and efficacy of SCS and DBS for DoC by systematically reviewing related literature by searching PubMed, EMBASE, Medline, and Cochrane Library. Twenty eligible studies with 608 patients were included in this study. Ten studies with 508 patients reported the efficacy of SCS for DoC, and the estimated overall effectiveness rate was 37%. Five studies with 343 patients reported the efficacy of SCS for VS, and the estimated effectiveness rate was 30%. Three studies with 53 patients reported the efficacy of SCS for MCS, and the estimated effectiveness rate was 63%. Five studies with 92 patients reported the efficacy of DBS for DoC, and the estimated overall effectiveness rate was 40%. Four studies with 63 patients reported the efficacy of DBS for VS, and the estimated effectiveness rate was 26%. Three studies with 19 patients reported the efficacy of DBS for MCS, and the estimated effectiveness rate was 74%. The adverse event rate of DoC was 8.1% and 18.2% after SCS and DBS, respectively. These results suggest that SCS and DBS can be considered reasonable treatments for DoC with considerable efficacy and safety.

The current state, challenges, and future directions of deep brain stimulation for obsessive compulsive disorder

INTRODUCTION

Obsessive-compulsive disorder (OCD) is clinically and pathologically heterogenous, with symptoms often refractory to first-line treatments. Deep brain stimulation (DBS) for the treatment of refractory OCD provides an opportunity to adjust and individualize neuromodulation targeting aberrant circuitry underlying OCD. The tailoring of DBS therapy may allow precision in symptom control based on patient-specific pathology. Progress has been made in understanding the potential targets for DBS intervention; however, a consensus on an optimal target has not been agreed upon.

AREAS COVERED

A literature review of DBS for OCD was performed by querying the PubMed database. The following topics were covered: the evolution of DBS targeting in OCD, the concept of an underlying unified connectomic network, current DBS targets, challenges facing the field, and future directions which could advance personalized DBS in this challenging population.

EXPERT OPINION

To continue the increasing efficacy of DBS for OCD, we must further explore the optimal DBS response across clinical profiles and neuropsychiatric domains of OCD as well as how interventions targeting multiple points in an aberrant circuit, multiple aberrant circuits, or a connectivity hub impact clinical response. Additionally, biomarkers would be invaluable in programming adjustments and creating a closed-loop paradigm to address symptom fluctuation in daily life.

Analysis of the influences of social isolation on cognition and the therapeutic potential of deep brain stimulation in a mouse model

Background

Social interaction is a fundamental human need. Social isolation (SI) can have negative effects on both emotional and cognitive function. However, it is currently unclear how age and the duration of SI affect emotion and recognition function. In addition, there is no specific treatment for the effects of SI.

Methods

The adolescence or adult mice were individually housed in cages for 1, 6 or 12 months and for 2 months to estabolish SI mouse model. We investigated the effects of SI on behavior in mice at different ages and under distinct durations of SI, and we explored the possible underlying mechanisms. Then we performed deep brain stimulation (DBS) to evaluate its influences on SI induced behavioral abnormalities.

Results

We found that social recognition was affected in the short term, while social preference was damaged by extremely long periods of SI. In addition to affecting social memory, SI also affects emotion, short-term spatial ability and learning willingness in mice. Myelin was decreased significantly in the medial prefrontal cortex (mPFC) and dorsal hippocampus of socially isolated mice. Cellular activity in response to social stimulation in both areas was impaired by social isolation. By stimulating the mPFC using DBS, we found that DBS alleviated cellular activation disorders in the mPFC after long-term SI and improved social preference in mice.

Conclusion

Our results suggest that the therapeutic potential of stimulating the mPFC with DBS in individuals with social preference deficits caused by long-term social isolation, as well as the effects of DBS on the cellular activity and density of OPCs.

Network targets for therapeutic brain stimulation: towards personalized therapy for pain

Precision neuromodulation of central brain circuits is a promising emerging therapeutic modality for a variety of neuropsychiatric disorders. Reliably identifying in whom, where, and in what context to provide brain stimulation for optimal pain relief are fundamental challenges limiting the widespread implementation of central neuromodulation treatments for chronic pain. Current approaches to brain stimulation target empirically derived regions of interest to the disorder or targets with strong connections to these regions. However, complex, multidimensional experiences like chronic pain are more closely linked to patterns of coordinated activity across distributed large-scale functional networks. Recent advances in precision network neuroscience indicate that these networks are highly variable in their neuroanatomical organization across individuals. Here we review accumulating evidence that variable central representations of pain will likely pose a major barrier to implementation of population-derived analgesic brain stimulation targets. We propose network-level estimates as a more valid, robust, and reliable way to stratify personalized candidate regions. Finally, we review key background, methods, and implications for developing network topology-informed brain stimulation targets for chronic pain.

Future directions in psychiatric neurosurgery: Proceedings of the 2022 American Society for Stereotactic and Functional Neurosurgery meeting on surgical neuromodulation for psychiatric disorders

OBJECTIVE

Despite advances in the treatment of psychiatric diseases, currently available therapies do not provide sufficient and durable relief for as many as 30-40% of patients. Neuromodulation, including deep brain stimulation (DBS), has emerged as a potential therapy for persistent disabling disease, however it has not yet gained widespread adoption. In 2016, the American Society for Stereotactic and Functional Neurosurgery (ASSFN) convened a meeting with leaders in the field to discuss a roadmap for the path forward. A follow-up meeting in 2022 aimed to review the current state of the field and to identify critical barriers and milestones for progress.

DESIGN

The ASSFN convened a meeting on June 3, 2022 in Atlanta, Georgia and included leaders from the fields of neurology, neurosurgery, and psychiatry along with colleagues from industry, government, ethics, and law. The goal was to review the current state of the field, assess for advances or setbacks in the interim six years, and suggest a future path forward. The participants focused on five areas of interest: interdisciplinary engagement, regulatory pathways and trial design, disease biomarkers, ethics of psychiatric surgery, and resource allocation/prioritization. The proceedings are summarized here.

CONCLUSION

The field of surgical psychiatry has made significant progress since our last expert meeting. Although weakness and threats to the development of novel surgical therapies exist, the identified strengths and opportunities promise to move the field through methodically rigorous and biologically-based approaches. The experts agree that ethics, law, patient engagement, and multidisciplinary teams will be critical to any potential growth in this area.

Safety, tolerability, and clinical and neural effects of single-dose psilocybin in obsessive-compulsive disorder: protocol for a randomized, double-blind, placebo-controlled, non-crossover trial

Background

Psilocybin may help treat obsessive-compulsive disorder (OCD). To date, only one open-label study of psilocybin for OCD exists, necessitating further investigation with a randomized controlled design. The neural correlates of psilocybin's effects on OCD have also not been studied.

Objectives

This first-of-its-kind trial aims to evaluate the feasibility, safety, and tolerability of psilocybin in the treatment of OCD, provide preliminary evidence on the effects of psilocybin on OCD symptoms, and elucidate neural mechanisms that may mediate psilocybin's effects on OCD.

Design

We use a randomized (1:1), double-blind, placebo-controlled, non-crossover design to examine the clinical and neural effects of either a single dose of oral psilocybin (0.25 mg/kg) or active placebo-control agent (250 mg of niacin) on OCD symptoms.

Methods and analysis

We are enrolling 30 adult participants at a single site in Connecticut, USA who have failed at least one trial of standard care treatment (medication/psychotherapy) for OCD. All participants will also receive unstructured, non-directive psychological support during visits. Aside from safety, primary outcomes include OCD symptoms over the past 24 h, assessed by the Acute Yale-Brown Obsessive-Compulsive Scale and Visual Analog Scale ratings. These are collected by blinded, independent raters at baseline and the primary endpoint of 48 h post-dosing. Total follow-up is 12 weeks post-dosing. Resting state neuroimaging data will be collected at baseline and primary endpoint. Participants randomized to placebo will be offered the chance to return for an open-label dose of 0.25 mg/kg.

Ethics statement

All participants will be required to provide written informed consent. The trial (protocol v. 5.2) was approved by the institutional review board (HIC #2000020355) and registered with ClinicalTrials.gov (NCT03356483).

Discussion

This study may represent an advance in our ability to treat refractory OCD, and pave the way for future studies of neurobiological mechanisms of OCD that may respond to psilocybin.

Genomics of severe and treatment-resistant obsessive-compulsive disorder treated with deep brain stimulation: a preliminary investigation

Individuals with severe and treatment-resistant obsessive-compulsive disorder (trOCD) represent a small but severely disabled group of patients. Since trOCD cases eligible for deep brain stimulation (DBS) probably comprise the most severe end of the OCD spectrum, we hypothesize that they may be more likely to have a strong genetic contribution to their disorder. Therefore, while the worldwide population of DBS-treated cases may be small (~300), screening these individuals with modern genomic methods may accelerate gene discovery in OCD. As such, we have begun to collect DNA from trOCD cases who qualify for DBS, and here we report results from whole exome sequencing and microarray genotyping of our first five cases. All participants had previously received DBS in the bed nucleus of stria terminalis (BNST), with two patients responding to the surgery and one showing a partial response. Our analyses focused on gene-disruptive rare variants (GDRVs; rare, predicted-deleterious single-nucleotide variants or copy number variants overlapping protein-coding genes). Three of the five cases carried a GDRV, including a missense variant in the ion transporter domain of KCNB1, a deletion at 15q11.2, and a duplication at 15q26.1. The KCNB1 variant (hg19 chr20-47991077-C-T, NM_004975.3:c.1020G>A, p.Met340Ile) causes substitution of methionine for isoleucine in the trans-membrane region of neuronal potassium voltage-gated ion channel KV2.1. This KCNB1 substitution (Met340Ile) is located in a highly constrained region of the protein where other rare missense variants have previously been associated with neurodevelopmental disorders. The patient carrying the Met340Ile variant responded to DBS, which suggests that genetic factors could potentially be predictors of treatment response in DBS for OCD. In sum, we have established a protocol for recruiting and genomically characterizing trOCD cases. Preliminary results suggest that this will be an informative strategy for finding risk genes in OCD.