The purpose of this study is to evaluate the efficacy, safety, and tolerability of two doses (12.5 and 50 mg) of NBI-98854 administered once daily (q.d.) for the treatment of tardive dyskinesia in subjects with schizophrenia or schizoaffective disorder.

Inclusion Criteria:

• Have a clinical diagnosis of schizophrenia or schizoaffective disorder and a clinical diagnosis of neuroleptic-induced tardive dyskinesia as defined in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), 333.82 (see Appendix 17.1) for at least 3 months prior to screening.
• Be receiving a stable dose of antipsychotic medication for a minimum of 30 days before study start. Subjects who are not using antipsychotic medication must have stable psychiatric status.
• Have the doses of concurrent medications and the conditions being treated be stable for a minimum of 30 days before study start and be expected to remain stable during the study.
• Subjects of childbearing potential must agree to use hormonal or two forms of nonhormonal birth control during the study.
• Female subjects must not be pregnant.
• Be in good general health and expected to complete the clinical study as designed.
• Have a body mass index (BMI) of 18 to 38 kg/m2 (both inclusive).
• Have adequate hearing, vision, and language skills to perform the procedures specified in the protocol.
• Have a negative urine drug screen (negative for amphetamines, barbiturates, benzodiazepine, phencyclidine, cocaine, opiates, or cannabinoids) at screening and study start, except for any subject receiving a stable dose of benzodiazepine.
• Have a negative alcohol breath test at screening and study start.

Exclusion Criteria:

• Have an active clinically significant unstable medical condition within 1 month (30 days) prior to screening.
• Have a history of substance dependence or substance (drug) or alcohol abuse within the 3 months before study start(nicotine and caffeine dependence are not exclusionary).
• Have a known history of neuroleptic malignant syndrome.
• Have a significant risk of suicidal or violent behavior.
• Receiving any excluded concomitant medication such as reserpine, metoclopramide, stimulants, or tetrabenazine
• Receiving medication for the treatment of tardive dyskinesia.
• Have a positive human immunodeficiency virus antibody, (HIV-Ab), hepatitis B surface antigen (HBsAg), or hepatitis C virus (HCV) antibody result at screening or have a history of positive result.
• Have received an investigational drug within 30 days before screening or plan to use an investigational drug (other than NBI-98854) during the study.
• Have an allergy, hypersensitivity, or intolerance to tetrabenazine.
• Have had previous exposure with NBI-98854.