Thalamic volume in pediatric obsessive-compulsive disorder patients beforeand after cognitive behavioral therapy

Background: Neurobiologic abnormalities in the thalamus have been implicate d in the pathophysiology of obsessive-compulsive disorder. We recently repo rted increased thalamic volume in treatment-naive pediatric obsessive-compu lsive disorder patients versus case-matched healthy comparison subjects tha t decreased to levels comparable to control subjects after effective paroxe tine therapy. To our knowledge, no prior study has measured neuronanatomic changes in the thalamus of obsessive-compulsive disorder patients near illn ess onset before and after cognitive behavioral therapy. Methods: Volumetric magnetic resonance imaging studies were conducted in 11 psychotropic drug-naive 8-17-year-old children with obsessive-compulsive d isorder before and after 12 weeks of effective cognitive behavioral therapy monotherapy (greater than or equal to 30% reduction in obsessive-compulsiv e disorder symptom severity). Results: No significant change in thalamic volume was observed in obsessive -compulsive disorder patients before and after cognitive behavioral therapy . Conclusions: Our findings suggest that reduction in thalamic volume after p aroxetine therapy may be specific to paroxetine treatment and not the resul t of a general treatment response or spontaneous improvement, These results are preliminary in view of the small sample studied (C) 2000 Society of Bi ological Psychiatry.