Is twice daily LF-rTMS a viable treatment option for treatment-resistant OCD? Results from an open-label feasibility study

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.

A transdiagnostic review of safety, efficacy, and parameter space in accelerated transcranial magnetic stimulation

BACKGROUND

Accelerated transcranial magnetic stimulation (aTMS) is an emerging delivery schedule of repetitive TMS (rTMS). TMS is "accelerated" by applying two or more stimulation sessions within a day. This three-part review comprehensively reports the safety/tolerability, efficacy, and stimulation parameters affecting response across disorders.

METHODS

We used the PubMed database to identify studies administering aTMS, which we defined as applying at least two rTMS sessions within one day.

RESULTS

Our targeted literature search identified 85 aTMS studies across 18 diagnostic and healthy control groups published from July 2001 to June 2022. Excluding overlapping populations, 63 studies delivered 43,873 aTMS sessions using low frequency, high frequency, and theta burst stimulation in 1543 participants. Regarding safety, aTMS studies had similar seizure and side effect incidence rates to those reported for once daily rTMS. One seizure was reported from aTMS (0.0023% of aTMS sessions, compared with 0.0075% in once daily rTMS). The most common side effects were acute headache (28.4%), fatigue (8.6%), and scalp discomfort (8.3%), with all others under 5%. We evaluated aTMS efficacy in 23 depression studies (the condition with the most studies), finding an average response rate of 42.4% and remission rate of 28.4% (range = 0-90.5% for both). Regarding parameters, aTMS studies ranged from 2 to 10 sessions per day over 2-30 treatment days, 10-640 min between sessions, and a total of 9-104 total accelerated TMS sessions per participant (including tapering sessions). Qualitatively, response rate tends to be higher with an increasing number of sessions per day, total sessions, and total pulses.

DISCUSSION

The literature to date suggests that aTMS is safe and well-tolerated across conditions. Taken together, these early studies suggest potential effectiveness even in highly treatment refractory conditions with the added potential to reduce patient burden while also expediting response time. Future studies are warranted to systematically investigate how key aTMS parameters affect treatment outcome and durability.

Continuous Theta-Burst Stimulation Over the Right Orbitofrontal Cortex in Treatment-Resistant Obsessive-Compulsive Disorder Treatment: A Randomized Sham-Controlled Trial

Purpose

Examining whether modulation of right orbitofrontal cortex (OFC) activity by continuous theta-burst stimulation (cTBS) affects obsessive-compulsive disorder (OCD) symptoms.

Patients and Methods

A total of 28 treatment-resistant OCD participants were treated with either active or sham cTBS of the OFC twice per day, for five days a week, for 2 weeks, in a double-blinded manner. Clinical response to treatment was determined using the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS).

Results

There were no statistically significant differences between the 2 groups after two weeks of treatment in the Yale-Brown Obsessive-Compulsive Scale score (group*time interaction, F2,20=0.996, p=0.387) and other secondary outcome measures, including anxiety symptoms and responder rates. Depressive symptoms improved significantly in the active group (p=0.027), but the significant difference disappeared at 6 weeks (p=0.089).

Conclusion

This is the first randomized controlled study using cTBS in the right OFC to observe the improvement of treatment-resistant OCD symptoms. It is safe to use cTBS, but 2 weeks of treatment is not enough to achieve a curative effect. Future studies are needed to explore more advanced stimulation parameters suitable for the treatment of OCD.

Clinical Trial Registration

www.chictr.org.cn, identifier ChiCTR2000034814.