**TMS for OCD**

**TMS for OCD**

#### Aron Tendler and Elyssa Sisko Aron Tendler and Elyssa Sisko Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.73594

#### **Abstract**

**Introduction**: Obsessive compulsive disorder (OCD) is a common disabling condition, which greater than 40% of patients do not respond to the available treatment options. Imbalances in the cortical-striatal-thalamic-cortical circuits have proven to be useful psychosurgical treatment targets making this circuit disorder an optimal target for intervention with TMS.

DOI: 10.5772/intechopen.73594

**Methods**: PubMed and clinicaltrials.gov were reviewed for sham-controlled therapeutic rTMS studies for OCD.

**Results**: Eighteen relevant studies are presented in a narrative fashion along with relevant methodological details, and distinctions.

**Conclusions**: High and low frequency stimulation to lateral prefrontal cortices does not appear to have consistent efficacy in the small studies done to date. Several small studies with non-blinded operators suggest that low frequency high intensity rTMS to the supplementary motor area with a figure-8 coil reduces OCD symptoms. A fully blinded multicenter center study is warranted to confirm this finding. A promising pilot study and a subsequent multicenter study of high frequency high intensity deep rTMS with the HAC/H7 coil to the bilateral prefrontal orbitofrontal and anterior cingulate cortices were completed with positive results. Many areas of uncertainty remain, such as the optimal state of the circuitry during stimulation and identifying a priori biomarkers for responders and non-responders to specific protocols.

**Keywords:** rTMS, dTMS, TMS, OCD, ACC, SMA, OFC, obsessive compulsive disorder

## **1. Introduction**

The DSM 5 criteria for obsessive compulsive disorder (OCD) are specific. Patients can have either obsessions, compulsions or both. Obsessions are defined as unwanted thoughts, images or urges. Compulsions are repetitive behaviors or mental acts that are done in response to an obsession or a rigid rule with the aim of reducing anxiety. However, the extent of the compulsion

Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons

is either unrealistic or excessive. Obsessions and/or compulsions must take up at least 1 h a day, and though it may relieve their anxiety, it should not be pleasurable to the patient. In addition to the time component, the obsessions-compulsions should cause significant impairment in social or occupational functioning. The OCD symptoms should not be due to a substance or another disorder. Specifiers for OCD in the DSM 5 include the degree of insight (good, fair, poor, absent, delusional beliefs) and tic related [1].

to be 48% [2]. The overall recurrence rate (another first degree family member getting OCD) is about 50%, which is higher with Tourette's and tics as well as childhood onset. It is lower with

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http://dx.doi.org/10.5772/intechopen.73594

At the present time**,** exposure and response prevention should probably be the first line treatment for non-comorbid OCD. Pharmacologic interventions with significant evidence for efficacy, specifically with 8–12 weeks of medication results with greater than 30% improvement for 40–60% of OCD patients include several selective serotonin reuptake inhibitors: Fluoxetine, Paroxetine, Fluvoxamine and Sertraline in the USA; Citalopram and Escitalopram

Neurosurgery has shown promising outcomes where 58–67% of patients showed marked improvement in numerous studies even for patients who have refractory OCD (failed three medications and had 6 months of exposure and response prevention). The primary ablation anatomical targets are the fiber tracts that connect the cortex to thalamic nuclei, the anterior limb of the internal capsule and the cingulate gyrus. Nevertheless, neurosurgical procedures

Deep brain stimulation (DBS) has several advantages over ablation. Surgeons using DBS can potentially achieve a clinical effect without producing an irreversible lesion. The efficacy of

Over 1% of the population has no improvement from current approved treatments. Even the 1% that benefits from current approved treatments is actually still quite affected by their OCD. We use improvement criteria in OCD trials rather than response and remission, similar to schizophrenia. Schizophrenia affects 1% of the population, and there are over 20 antipsychotics available in most countries. OCD affects 2.3% of the population, and there are only 5 approved medications.

Several inclusive models have been suggested to explain the neurobiology of OCD. One is an executive dysfunction model, where there are deficits in impulse control and inhibition of behaviors. Another is a modulatory control model, where the main dysfunction is in regulating socially appropriate behaviors. A recent model proposes OCD as an uncertainty disorder where there is an imbalance between input and input suppression [5]. Regardless of the model, there is abnormal activity in a region of the cortical-striatal-thalamic-cortical circuits. These are multiple parallel interconnected loops between cortical and subcortical areas whose role is to screen out which actions are selected and which are considered maladaptive and

pure OCD of adult onset [3].

**3. Current available treatment options for OCD**

also yield reports of transient and persistent adverse effects [4].

in Europe; and the tricyclic, Clomipramine.

ablative lesions appears to be similar to DBS.

**4. Why do we need TMS for OCD?**

**5. OCD as a circuit disorder**
