Addressing Involuntary Movements in Tardive Dyskinesia

Inclusion Criteria:

• History of using a dopamine receptor antagonist for at least 3 months
• Clinical diagnosis of tardive dyskinesia and has had symptoms for at least 3 monthsprior to screening
• Subjects with underlying psychiatric diagnosis are stable and have no change inpsychoactive medications
• Have a mental health provider and does not anticipate any changes to treatment regimenin the next 3 months
• History of being compliant with prescribed medications
• Able to swallow study drug whole
• Be in good general health and is expected to attend all study visits and completestudy assessments
• Female subjects must not be pregnant and must agree to an acceptable method ofcontraception throughout the study

Exclusion Criteria:

• Currently receiving medication for the treatment of tardive dyskinesia
• Have a neurological condition other than tardive dyskinesia that may interfere withassessing the severity of dyskinesias
• Have a serious untreated or undertreated psychiatric illness
• Have recent history or presence of violent behavior
• Have unstable or serious medical illness
• Have evidence of hepatic impairment
• Have evidence of renal impairment
• Have known allergy to any component of SD-809 or tetrabenazine
• Has participated in an investigational drug or device trial and received study drug ordevice within 30 days
• Have acknowledged use of illicit drugs
• Have a history of alcohol or substance abuse in the previous 12 months