Efficacy of transcranial magnetic stimulation in the treatment of Obsessive-compulsive disorder

Abstract

Background: Obsessive-compulsive disorder (OCD) is a chronic and debilitating disease characterised by obsessions and compulsions that cause anxiety to the patient and his family. Its prevalence is around 2 to 3% in the general population, and despite being responsive to treatment, 40-60% of patients are not full responders and remain refractory. Therefore, new therapeutic options like transcranial magnetic stimulation (TMS) have been gaining interest recently due to their non-invasive nature and potentially promising results. However, there is not yet a consensus about its efficacy in this disease. The aim of this review is to assess the efficacy of TMS in the treatment of OCD, discussing some of the clinical trials available. Methods: A search was made in MEDLINE, through Pubmed, using the query: "Obsessive-Compulsive Disorder"[Mesh] AND "Transcranial Magnetic Stimulation"[Mesh]. Results: Several demographic, clinical and technique-related variables of 16 clinical trials were analysed, along with their outcome. Most of the trials revealed promising results in three cortical areas: dorsolateral pre-frontal cortex, supplementary motor area and orbitofrontal cortex. However, their statistical power is affected by their small sample size and heterogeneity of parameters, which limits critical analysis and comparison of results. Depression was also identified as a possible confounding factor, which could predispose to positive results. Conclusion: The distinct characteristics of the clinical trials make it impossible to generalise the effects of this technique in OCD. More robust studies, preferably without comorbid psychiatric disorders, are necessary to better evaluate the efficacy of this technique.