Cholinergic mechanisms in Tourette syndrome.

To examine the role of the cholinergic system in Tourette syndrome, we administered intramuscular physostigmine and scopolamine hydrobromide to 10 patients, evaluating both motor tics and involuntary vocalizations. Patients showed a consistent abatement of motor tics and exacerbation of vocal tics after scopolamine injection. The scopolamine effect was reversed by physostigmine. These data suggest that the cholinergic system plays a role in the pharmacologic pathophysiology of Tourette syndrome. The pharmacology of vocal and motor tics may differ, and cholinergic manipulation may benefit some patients.