title: Polarity-dependent effects of transcranial direct current stimulation in obsessive-compulsive disorder.
abstract: About one third of patients with obsessive-compulsive disorder (OCD) fail to experience significant clinical benefit from currently available treatments. Hyperactivity of the presupplementary motor area (pre-SMA) has been detected in OCD patients, but it is not clear whether it is the primary cause or a secondary compensatory mechanism in OCD pathophysiology. Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique with polarity-dependent effects on motor cortical excitability. A 33-year-old woman with treatment-resistant OCD received 20 daily consecutive 2 mA/20 min tDCS sessions with the active electrode placed on the pre-SMA, according to the 10-20 EEG system, and the reference electrode on the right deltoid. The first 10 sessions were anodal, while the last 10 were cathodal. Symptoms severity was assessed using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) severity score. In the end of anodal stimulation, OCD symptoms had worsened. Subsequent cathodal stimulation induced a dramatic clinical improvement, which led to an overall 30% reduction in baseline symptoms severity score on the Y-BOCS. Our study supports the hypothesis that pre-SMA hyperfunction might be responsible for OCD symptoms and shows that cathodal inhibitory tDCS over this area might be an option when dealing with treatment-resistant OCD.
authors.affiliation: a Department of Clinical Neurosciences, Anesthesiology and Pharmachoutilization , University Hospital of Naples Federico II , Naples , Italy.
authors.forename: Giordano
authors.initials: G
authors.lastname: D'Urso
authors.affiliation: b Interdisciplinary Center for Applied Neuromodulation (CINA) , University Hospital, University of São Paulo , São Paulo , Brazil.|c Service of Interdisciplinary Neuromodulation (SIN), Laboratory of Neurosciences (LIM-27), Department and Institute of Psychiatry , University of São Paulo , São Paulo , Brazil.
authors.forename: Andre Russowsky
authors.initials: AR
authors.lastname: Brunoni
authors.affiliation: d Department of Neurosciences, Reproductive and Odontostomatological Sciences , University of Naples Federico II , Naples , Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Anastasia
authors.affiliation: d Department of Neurosciences, Reproductive and Odontostomatological Sciences , University of Naples Federico II , Naples , Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Micillo
authors.affiliation: d Department of Neurosciences, Reproductive and Odontostomatological Sciences , University of Naples Federico II , Naples , Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: de Bartolomeis
authors.affiliation: e Department of Physiology, Pharmacology & Neuroscience, Sophie Davis School of Biomedical Education , City University of New York , New York , NY , USA.|f Division of Experimental Therapeutics, Department of Psychiatry , Columbia University/New York State Psychiatric Institute , New York , NY , USA.
authors.forename: Antonio
authors.initials: A
authors.lastname: Mantovani
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D009044:Motor Cortex / Q000503:physiopathology*; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D012720:Severity of Illness Index; D065908:Transcranial Direct Current Stimulation / Q000379:methods*; D016896:Treatment Outcome
keywords: OCD; TMS; brain stimulation; supplementary motor area; tDCS