Journal Article

Gray matter volumes in obsessive-compulsive disorder before and after fluoxetine or cognitive-behavior therapy: a randomized clinical trial

de Souza Duran, Fábio Luis, D'Alcante, Carina Chaubet, Lopes, Antonio Carlos, Diniz, Juliana Belo, Miguel, Euripedes Constantino, Busatto, Geraldo Filho, Bressan, Rodrigo Affonseca, Batistuzzo, Marcelo Camargo, Hoexter, Marcelo Queiroz, Deckersbach, Thilo, Shavitt, Roseli Gedanke, Dougherty, Darin Dean

2012

Overview

Serotonin reuptake inhibitors and cognitive-behavior therapy (CBT) are considered first-line treatments for obsessive-compulsive disorder (OCD). However, little is known about their modulatory effects on regional brain morphology in OCD patients. We sought to document structural brain abnormalities in treatment-naive OCD patients and to determine the effects of pharmacological and cognitive-behavioral treatments on regional brain volumes. Treatment-naive patients with OCD (n=38) underwent structural magnetic resonance imaging scan before and after a 12-week randomized clinical trial with either fluoxetine or group CBT. Matched-healthy controls (n=36) were also scanned at baseline. Voxel-based morphometry was used to compare regional gray matter (GM) volumes of regions of interest (ROIs) placed in the orbitofrontal, anterior cingulate and temporolimbic cortices, striatum, and thalamus. Treatment-naive OCD patients presented smaller GM volume in the left putamen, bilateral medial orbitofrontal, and left anterior cingulate cortices than did controls (p<0.05, corrected for multiple comparisons). After treatment with either fluoxetine or CBT (n=26), GM volume abnormalities in the left putamen were no longer detectable relative to controls. ROI-based within-group comparisons revealed that GM volume in the left putamen significantly increased (p<0.012) in fluoxetine-treated patients (n=13), whereas no significant GM volume changes were observed in CBT-treated patients (n=13). This study supports the involvement of orbitofronto/cingulo-striatal loops in the pathophysiology of OCD and suggests that fluoxetine and CBT may have distinct neurobiological mechanisms of action.

• Publisher: Nature Publishing Group
• Subject: Adult / Brain - drug effects / Brain - pathology / Cognitive Therapy / Female / Fluoxetine - therapeutic use / Humans / Image Processing, Computer-Assisted / Magnetic Resonance Imaging / Male / Middle Aged / Obsessive compulsive disorder / Obsessive-Compulsive Disorder - drug therapy / Obsessive-Compulsive Disorder - pathology / Obsessive-Compulsive Disorder - psychology / Obsessive-Compulsive Disorder - therapy / Organ Size - drug effects / Original / Serotonin Uptake Inhibitors - therapeutic use / Treatment Outcome