Dopamine D-2 receptor imaging in Gilles de la Tourette syndrome

Objectives - To examine postsynaptic dopamine D-2 receptors in Tourette syndrome (TS). Material and methods - Seventeen patients and a control group were investigated using single photon emission computed tomography (SPECT) and iodobenzamide (I-123-IBZM). Results - In neuroleptic treated patients (n = 7) I-123-IBZM-binding was significantly reduced compared to both normal controls (P < 0.0001) and unmedicated patients (P < 0.001). In unmedicated patients (n = 10) mean binding ratio did not differ from that of control group. Patients in advanced stages of the disease, however, revealed significantly reduced relative striatal binding compared to patients in the early stages (P < 0.005) and normal controls (P < 0.0001). Conclusion - The results lend further support to the hypothesis that the dopamine receptor is involved in TS pathology. During the natural course of the disease ties often improve in early adulthood. It is suggested that this spontaneous recovery from ties may be associated with reduced receptor binding capacity.