No change in striatal dopamine re-uptake site density in psychotropic drug naive and in currently treated Tourette's disorder patients: a [(123)I]-beta-CIT SPECt-study.

BACKGROUND: There is evidence that Tourette's disorder (TD) is associated with abnormalities in the dopaminergic system involving the dopamine transporter (DAT). Data from [(123)I]-beta-CIT single photon emission computed tomography (SPECT) studies and postmortem findings concerning DAT densities in TD patients are not conclusive. The objective of our study was to measure DAT densities with [(123)I]-beta-CIT binding in TD patients who were either psychotropic drug naive or currently treated with antipsychotics (AP) and healthy controls.

METHOD: Altogether 20 TD patients were investigated. A total of 15 patients were psychotropic drug naive and five were currently treated with AP. Ten psychotropic drug naive patients were compared with ten age and sex matched healthy subjects. Five currently treated patients were compared with five age and sex matched psychotropic drug naive TD patients. The investigation was carried out using [(123)I]-beta-CIT (2-beta-carbomethoxy-3-beta(4-iodophenyl)-tropane and SPECT. Regions of interest (ROI) were drawn over the striatum and the cerebellum.

RESULTS: The DAT densities measured by the striatal/cerebellar (S/C) binding ratio did not differ between drug naive TD patients and the controls. The difference between currently AP treated and psychotropic drug naive TD patients did not reach the level of significance. There was no correlation between the ratio and severity of tics and illness.

CONCLUSION: Our study with psychotropic drug naive TD patients contributed to clarify the inconsistent results concerning the DAT.