Decreased presynaptic dopamine function in the left caudate of depressed patients with affective flattening and psychomotor retardation

Objective: The study assessed striatal presynaptic dopamine function in pat ients with different subtypes of depression. Method: Magnetic resonance imaging and positron emission tomography with [F -18]fluorodopa ([F-18]DOPA) were used to compare six depressed patients wit h marked affective flattening and psychomotor retardation, six depressed pa tients with marked impulsivity and anxiety, and 10 healthy comparison subje cts. Depressed patient groups were matched for severity of depression. Results: [F-18]DOPA uptake K-i values in the left caudate were significantl y lower in patients with psychomotor retardation than in patients with high impulsivity and in comparison subjects. Conclusions: These results suggest that left caudate dopamine function diff ers between depressed patients with psychomotor retardation and those with impulsivity and provide direct evidence of a link between dopamine hypofunc tion and psychomotor retardation in depression.