Dopaminergic function in depressed patients with affective flattening or with impulsivity:: [18F]fluoro-L-dopa positron emission tomography study with voxel-based analysis

A decreased striatal presynaptic dopaminergic function has been reported in depressed patients with affective flattening and psychomotor retardation, using F-18-fluorodopa positron emission tomography and regions-of-interest. The present study aimed to investigate regional[F-18]dopa uptake in mesolimbic and mesocortical dopaminergic projections with the hypothesis that there should be a decrease in mesolimbic [F-18]dopa uptake associated with affective flattening and psychomotor retardation. [18F]Dopa-positron emission tomography and anatomical magnetic resonance imaging datasets from 12 screened depressed patients with either marked affective flattening and psychomotor retardation (n = 6) or with marked impulsivity (n = 6), and from eight healthy subjects, were analyzed using a voxel-based approach. Regional differences in [F-18]dopa uptake rate constant (K-i) values between the healthy group and the two depression subgroups were compared using both statistical parametric mapping and cluster-based regions-of-interest. Patients with affective flattening and psychomotor retardation had [F-18]dopa K-i decreases in the left caudate, bilateral putamen and nucleus accumbens, left parahippocampus and dorsal brainstem. Impulsive depressives had [F-18]dopa K-i decreases in the anterior cingulate and hypothalamus, and an increase in the right parahippocampal gyrus. These findings support distinct regional dysfunctions of monoamines depending on the depressive symptomatology. (c) 2006 Elsevier Ireland Ltd. All rights reserved.