ENHANCING COGNITIVE-BEHAVIORAL THERAPY FOR OBSESSIVE-COMPULSIVE DISORDER WITH TRANSCRANIC MAGNETIC STIMULATION: A PROOF OF CONCEPT

Abstract

Cognitive behavioral therapy (CBT) is a well established first line treatment for obsessive compulsive disorder (OCD). It consists of a cognitive and a behavioral treatment (exposure and response prevention therapy (ERP)) [1]. The goal of the cognitive treatment is the cognitive restructuring of meta-cognitions while the goal of exposure therapy is enhancing and facilitating patients’ fear extinction processes in front of the feared object, situation or thought/obsession. Several studies have tried to enhance fear extinction through pharmacological agents with mixed results [2]. High-frequency repetitive transcranial magnetic stimulation (HF-rTMS), through its capacity to induce long-term potentiation, is able to modulate learning processes and hippocampal plasticity [3]. Moreover, several studies showed that HF-rTMS over the dosrsolateral prefrontal cortex (DLPFC) is able to induce better working memory performance after active stimulation [4]. Thus, rTMS could represent a promising tool to enhance cognitive restructuring and fear extinction learning processes during the cognitive-behavioral treatment sessions. Recently, we published a case report of a patient treated with HF-rTMS over the left DLPFC before each ERP session [5]. Here we adopted a new protocol in order to potentiate both the cognitive and the behavioral part of the treatment. The aim of this study was to evaluate the potential CBT enhancing effect of HF-rTMS over the left DLPFC in OCD patients who failed to respond to a previous CBT trial. Each patient underwent a 16 sessions CBT trial (1 session per week, 50/60 minutes per session). The first six sessions were dedicated to establishing an individual hierarchy of obsessions and compulsions and to a cognitive restructuring of meta-cognitions. The following 10 sessions focused on in vivo ERP exercises. For the first six sessions patients underwent a HF-rTMS session over the left DLPFC immediately before the session in order to enhance working memory processes during cognitive restructuring of metacognitions (6 stimulation sessions). Subsequently, each exposure session was immediately followed by an HF-rTMS session over the left DLPFC (10 stimulation sessions). During the treatment, 32 trains of 5 seconds has been applied at 10 Hz and at 110% of the left motor trheshold over the left DLPFC, with a 25 seconds inter-train interval (a total of 1600 stimuli per session). No pharmacological treatment changes were allowed during the CBT trail and patients were stable on their undergoing medications since 4 weeks before starting the CBT sessions. We enrolled two OCD patients (with prominent checking and symmetry/ordering symptoms respectively) who failed a previous CBT trial and showed only slight depressive symptoms. At the end of the 16 CBT sessions patients showed a 35% and 30% symptoms reduction on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) respectively. HF-rTMS was well tolerated. rTMS could represent e tolerable tool in order to enhance the effect of CBT with exposure and response prevention techniques in patients with obsessive-compulsive disorder.