Treatment-Resistant Obsessive Compulsive Disorder: An Evaluation Study of the Augmentation Effect of Low-Frequency Repetitive Transcranial Magnetic Stimulation

Abstract

Background: Thelifetime prevalence of obsessive-compulsive disorders (OCD) is estimated to be around 3% in the general population. Selective serotonin reuptake inhibitors (SSRIs) are considered to be the primary treatment strategy of OCD in addition to psychotherapy. Unfortunately, current medications, augmentation strategies, and behavioral therapies fail to provide adequate benefits in many cases. A large percentage of patients (40-60%) do not show satisfactory response to the standard treatments, some of them experiencing a chronically deteriorating course, leading to marked interpersonal and occupational impairments. In recent years, non-invasive neuromodulatory techniques such as repetitive transcranial magnetic stimulation have been increasingly studied as potential adjunct or alternative therapies for a wide range of neurological and psychiatric conditions including pain disorder, depression, and stroke rehabilitation and OCD. Aims: the aim of this work to evaluate rTMS as an augmentation strategy in treatment-resistant OCD, to test the potential value oflow frequency rTMS to SMA,orbitofrontal cortex and right DLPFC in the treatment of resistant OCD and to compare between the therapeutic values of applying the TMS coil to those different areas of the cortex. Patients and Methods: This study was carried out in Psychiatry, Neurology and Neurosurgery Center, Tanta University from September 2017 to November 2019. Eighty patients (52 females and 28 males) aging between 18 and 65 years underwent complete psychiatric evaluation, including full medical history, psychiatric and physical examination and diagnosed as having OCD accordingto DSM-5 with failure of at least two adequate therapeutic trials of SRIs. Results: Before rTMS sessions there was no statistical significant difference between the three active groups and the sham group regarding the scores onYale-Brown obsessive compulsive scale,Hamilton anxiety rating scale, Hamilton depression rating scale and Clinical global impression scale. Results after rTMS sessions revealed the following: Active rTMS on the SMA, the left OFC and right DLPFC was associated with marked improvement in YBOCS, Hamilton anxiety rating scale, Hamilton Depression rating scale and clinical global impression scale. The most significant improvement in Yale Brown Obsessive Compulsive scale was obtained when the brain target was the SMA. The most significant improvement in anxiety rating scale and depression ratingscale was obtained when the brain target was the left OFC. Sham group didnt have significant improvement through the study. Conclusions: We can thus conclude that low frequency rTMS is significantly effective as an adjunctive treatment for resistant OCD and that the SMA is the most effective brain target.