Psychobiological theories of mood disorders have been concerned mainly with noradrenaline
and serotonin. There exists, however, a recent upsurge of interest in dopamine. We
have used single photon emission computed tomography and 123I-iodobenzamide, a high-affinity
ligand for D2 receptors, to study these receptors in depression. Subjects were 21
(unipolar) depressed inpatients and 11 normal controls. The mean basal ganglia/cerebellum
uptake ratio was 1.94 (+/- 0.27) in the depressed patients versus 1.74 (+/- 0.17)
in the controls. This difference was statistically significant (Mann-Whitney U test,
p = 0.025). These data could indicate an increase of D2 receptor density in depression.