Dopamine D-2 receptor binding before and after treatment of major depression measured by [I-123]IBZM SPECT

Fifteen patients fulfilling DSM-IV criteria for major depression were inves tigated with the specific dopamine D-2 receptor antagonist [I-123]iodobenza mide (IBZM). Two single photon emission computed tomography (SPECT) examina tions were performed before and after 6 weeks of treatment with a selective serotonin re-uptake inhibitor (SSRI). Striatal D-2 receptor binding was ca lculated and normalized to the cerebellum. In a non-psychiatric control gro up (n = 17), which was investigated once with [I-123]IBZM and SPECT, striat al IBZM binding decreased significantly with age (0.092 per decade). The ag e-dependent correlation was lower in subjects with major depression and did not reach statistical significance. There was no significant difference in mean IBZM binding between depressives and control subjects. Age-corrected baseline IBZM binding in the striatum was significantly lower in treatment responders than in depressed non-responders and control subjects. Furthermo re, in the depressive group there was a significant linear correlation betw een treatment response and change of D-2 receptor binding during treatment in the basal ganglia. IBZM binding increased in treatment responders and de creased in non-responders. In accordance with animal studies, the results s uggest an association between changes in the dopaminergic system and treatm ent response in major depression. (C) 1999 Elsevier Science Ireland Ltd. Al l rights reserved.