A Study to Evaluate the Effects of ABX-1431 on Patients With Tourette Syndrome

Principal Inclusion Criteria: * Patient is a male or female between the age of 18 and 65 years of age at the Screening Visit. * Patient has a diagnosis of Tourette Syndrome OR chronic motor tic disorder as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria. * Patient's Yale Global Tic Severity Scale (YGTSS) total tic sub-scale (TTS) results must be ≥ 18 (Range 0-50) at the Screening Visit. * Patients taking daily medications for symptoms of Tourette Syndrome \[e.g. neuroleptics (e.g. aripiprazole, risperidone) or selective serotonin reuptake inhibitors (e.g. fluoxetine)\] must be on a stable dose of medication for at least 30 days before the Screening Visit and must be expected to remain on a stable dose during this study. Principal Exclusion Criteria: * Patient is taking potent cytochrome P450 3A4/5 inducers \[e.g. carbamazepine, oxcarbazine, rifampin, St. John's Wort (Hypericum perforatum), or phenytoin\]. Patient is taking strong P450 3A4/5 inhibitors including atazanavir, bocepravir, clarithromycin, grapefruit juice, indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir, posaconazole, ritonavir, saquinavir, telithromycin, or voriconazole. * Patients with a diagnosis of any psychiatric comorbidity (obsessive compulsive disorder, attention deficit hyperactivity disorder) OR generalized anxiety disorder, depression or post-traumatic stress disorder that is unstable or requires alteration in therapy are excluded. Patients with a past history of psychosis or schizophrenia at any time are excluded. Patients with stable OCD or ADHD requiring no alteration in therapy may be enrolled.