Fluvoxamine treatment and D-2 receptors: a pet study on OCD drug-naive patients

Changes in D-2 receptors during antidepressant therapy have been reported in patients with major depressive disorder using PET/SPET. The aim of this study was to evaluate modifications in D-2 receptors that might occur in patients affected by obsessive-compulsive disorder (OCD) during serotonin reuptake sites inhibitors (SSRIs). To this purpose, we measured the in vivo binding of [C-11]raclopride ([C-11]Rac)in the brain of a group of OCD naive patients before and after the repeated administration of the inhibitor SSRI fluvoxamine. Eight patients with a Diagnostic and Statistical Manual of Mental Disorders IVth edition diagnosis of OCD completed the study undergoing a PET scan and a complete clinical evaluation before and during treatment with fluvoxamine. Patients have been compared also with a group of nine age-matched normal volunteers. Fluvoxamine treatment significantly improved clinical symptoms and increased [C-11]Rac binding potential (BP) in the basal ganglia of OCD patients (7.5 +/- 5.2, 6.9 +/- 6.9, and 9.9 +/- 9.3% in dorsal caudate, dorsal putamen, and ventral basal ganglia, respectively; p < 0.01) to values closer to those observed in the group of normal subjects. Chronic treatment with fluvoxamine induces a slight but significant increase in striatal [C-11]Rac BP of previously drug-naive OCD patients. The modifications in D-2 receptor availability might be secondary to fluvoxamine effects on serotoninergic activity.