Single photon emission computerized tomography assessment of cerebral dopamine D2 receptor blockade in depression before and after sleep deprivation--preliminary results.

The antidepressant properties of total sleep deprivation (TSD) have been well established. There is some evidence that TSD may improve depression by altering central dopamine (DA) function. We therefore studied five depressed TSD responders and five TSD nonresponders after sleep and after TSD and five controls after sleep with IBZM single photon emission computerized tomography (SPECT). Responders showed a significant decrease (Wilcoxon--test p < 0.05) of relative basal ganglia D2 receptor occupancy after TSD compared to nonresponders (change score responders versus nonresponders p < 0.05, U-test). The data are interpreted as a sign of an enhanced DA release in responders. The results confirm previous hypotheses of dopaminergic involvement in the therapeutic action of TSD and indirectly support a dopamine hypotheses of depression.