Patients ages 14 to 65 with a clinical diagnosis of tourette syndrome or chronic motor tic disorder as defined by DSM-IV-TR and evaluation of tic severity using the Yale Tic Scale (YGTSS). This criterion will be established by preliminary screening in the NINDS Movement Disorders Outpatient Clinic. Structure Clinical Interview for (DSMIV SCID) will be administered to all subjects to ensure that strict DSM-IV criteria for Tourette syndrome have been met and to assess for possible comorbid psychiatric disorders.