Inclusion Criteria:• Subjects must have Tourette's Syndrome (TS) based on the clinician-administered Diagnostic Confidence Index (DCI) for TS.
* Subjects must exhibit both motor and vocal tics.
* Subjects must have a minimum score of 20 at both Screening and Baseline (just prior to the first treatment) on the Yale Global Tic Severity Scale.
* Subjects must be age (≥ 7 to \< 18 years of age)
* Subjects must weigh ≥ 20 kg (45 lbs)
* Adolescent females of childbearing potential who are sexually active must be using effective contraception (i.e., oral contraceptives, intrauterine device, double barrier method of condom and spermicide) and agree to continue use of contraception for the duration of their participation in the study. They must also agree to use contraception for 30 days after their last dose of study drug.
* Sexually active male subjects must use a barrier method of contraception during the study and agree to continue the use of male contraception for at least 30 days after the last dose of study drug.
* Subject's parent or legal guardian must execute a written informed consent.
* Subject must execute a written informed assent.
Exclusion Criteria:
* Subjects who have unstable medical illness or clinically significant abnormalities on laboratory tests, or ECG at Screening.
* Subjects with a major depressive episode in the past 2 years
* Subjects with a history of attempted suicide
* Subjects with clinically significant suicidality (based on the Columbia Suicide Rating Scale (C-SSRS)
* Subjects with a first-degree relative with a major depressive episode that resulted in any psychiatric hospitalization, or attempted/ completed suicide with the exception of a hospitalization for post-partum depression.
* Subjects with a history of seizures (excluding febrile seizures that occurred \>2 years in the past)
* Subjects with a myocardial infarction within 6 months.
* Girls who are currently pregnant or lactating.
* Subjects who have a need for medication (other than ecopipam) with possible effects on TS symptoms (i.e., lithium, psychostimulants)
* Subjects who have a need for medications which would have unfavorable interactions with ecopipam, e.g., dopamine antagonists or agonists \[including bupropion\], tetrabenazine, or monoamine oxidase inhibitors.
* Subjects with a lifetime history of bipolar disorder type I or II, dementia, schizophrenia, or any psychotic disorder determined by the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders - 4th Edition (DSM-IV) Axis-I Disorders (SCID).
* Subjects with current or recent (past 3 months) DSM-IV substance abuse or dependence (with the exception of nicotine).
* Subjects with positive urine drug screen (cocaine, amphetamine, methamphetamine, tetrahydrocannabinol (THC), benzodiazepines, barbiturates, phencyclidine (PCP), opiates) at Screening. Subjects with urine positive only for benzodiazepines and/or marijuana (i.e., a user but not an abuser as based on DSM-IV criteria) may be eligible.
* Subjects who have had previous treatment with ecopipam.
* Subjects who have had treatment with:
* investigational medication within 3 months of starting study
* depot neuroleptics within 3 months of starting study
* other psychotropics with possible effects on TS symptoms (i.e., lithium, tetrabenazine) within 2 weeks prior to Screening.
* oral neuroleptics within 4 weeks
* selective serotonin reuptake inhibitors unless the dosage has been stable for a minimum of 4 weeks prior to study start and not prescribed to relieve the neurological signs of TS
