Abstract
The relationships between neuropsychological performance and urinary amine metabolite levels (HVA, 5-HIAA, MHPG) were examined in a sample of 27 medication-free patients with Tourette's Syndrome. Correlations with specific metabolites indicated neuropsychological deficit associated with higher levels of HVA and lower levels of 5-HIAA. Variables computed to express the interaction of the various neurotransmitter systems provided strong and consistent support for such interactions in the underlying mechanism of the neurobehavioral deficits observed in these patients. The implications of these findings and directions for future research were discussed.