PET brain imaging with [11C](+)McN5652 shows increased serotonin transporter availability in major depression

Background: Alterations in the brain serotonin (5-HT) system have been found in patients with depression. We used the selective 5-HT transporter site ligand [C-11](+)McN5652 and positron emission tomography (PET) to examine the hypothesis that alterations in 5-HT transporter levels may be present in selected regions of the brain in depressed patients. Methods: Four drug free depressed patients and four healthy control subjects were studied using [C-11](+)McN5652 and PET The distribution volume (DV) ratio of the PET ligand in selected regions of interest (ROIs) compared to cerebellum were calculated for the ROIs. Results: Patients showed significantly larger DV ratios in the left frontal cortex (P = 0.013) and right cingulate cortex (P = 0.043) compared to control subjects. Limitation: The sample size was modest with gender differences between the subject groups. The PET agent, [C-11](+)McN5652, may have a lower binding affinity for the 5-HT transporter in the cortical regions compared to other brain regions. Conclusion: These findings suggest that 5-HT transporter sites may be increased in the frontal and cingulate cortices of depressed patients. These alterations in 5-HT transporter sites may be of pathophysiologic significance in the etiology of depression and its treatment. (C) 2004 Elsevier B.V. All rights reserved.