Dopamine Transporter Change in Bupropion Responsive and Non-Responsive Depressive Patients

The role of serotonin in depression has been widely discussed in many researches. Dopamine may play some role in the pathophysioloy of depression, but just a few small studies had mentioned about it. The newer antidepressant, bupropion (norepinephrine and dopamine reuptake inhibitor, NDRI) is thought to exert its antidepressive effect by blocking the dopamine transport (DAT). But just a few clinical research and data were noted, especially about the dopamine transporter activity in relation to the efficacy in treating depressive patients with bupropion. The purpose of our study is to evaluate the possibly different change of DAT activity in medication naive 40 major depressive patients receiving bupropiron treatment, 300 mg per day, for eight weeks.We use 99mTc-TRODAT-1 SPECT to evaluate the DAT activity and will compare the possible difference between bupropion responsive and non-responsive depressive patients. The definition of response is HAMD score with 50 % reduction in 8 weeks』treatment. These patients will receive TRODAT neuroimaging at baseline and 8 weeks after treatment with well-explained informed consent. We presume that the dopaminergic regulation itself may differ from individual to individual in depressed patients. This can be a possible explanation for the discordance: the DAT is reduced possibly only in certain patients, not in the whole depressive populations. The further survey to explore the possible subtypes of depressive disorders is important, for example, dopamine-sensitive subtype, serotonin-responsive subtype, or others.We really hope this preliminary study will give us some way to approach the further pathophysioloy of depressive disorder, and to reduce the increasing social economic burdens of depression in current and further humans health.

Project ID:PC9706-0967
External Project ID:NSC96-2314-B182-027-MY2