UPTAKE OF TC-99M-EXAMETAZIME SHOWN BY SINGLE-PHOTON EMISSION COMPUTERIZED-TOMOGRAPHY IN OBSESSIVE-COMPULSIVE DISORDER COMPARED WITH MAJOR DEPRESSION AND NORMAL CONTROLS

Twelve patients with obsessive-compulsive disorder (OCD) were investig ated at rest using single photon emission computerized tomography with Tc-99m-exametazime. The uptake of Tc-99m-exametazime was expressed re lative to calcarine/occipital cortex. Patients were matched for drug t reatment with 12 patients with a major depressive episode and the pati ent groups were compared with a control group. Significant bilateral d ecreases in tracer uptake were confined to basal ganglia in the OCD gr oup. There was a paradoxical positive correlation between anxiety rati ngs and tracer uptake to basal ganglia in the OCD group. The findings confirm that the functional topography of OCD implicates altered funct ion in the basal ganglia.