We review historical, conceptual, clinical and diagnostic criteria as well as present genetic and neurochemical factors of tic disorders. Epidemiologic data sugest that tic is an organic disease with autosomal dominant transmission. We emphasize imunohistochemical studies particularly related to the dopaminergic, noradrenergic and serotonergic systems. These modulate the activity of the cortico-striato-thalamocortical circuits implicated in both Tourette's syndrome and obsessive-compulsive disorder.
tics; Gilles de la Tourette syndrome; genetics; dopaminergic activity