This is a single-center, open-label study of AUSTEDO in study subjects with dystonia. The study will provide preliminary experience of the safety, tolerability, and clinical activity of AUSTEDO in study subjects with dystonia. Study duration will be up to 13 weeks from screening (Visit 1) to the post treatment evaluation (Visit 5). Treatment period from drug initiation to final on-treatment Visit will be 12 weeks, or less, as follows: during the ramp-up period, study drug will start at 12 mg/day (6 mg twice daily) and will be titrated weekly by 6 mg/day increments until either 1) the maximal allowable dose (48 mg/day) is reached, or 2) dose-limiting side-effects occur. In study subjects receiving a strong CYP2D6 inhibitor, the maximum allowed dose of AUSTEDO will be 36 mg/day, reducing study duration (due to a reduction in the ramp-up period) to 11 weeks. Study subjects who experience dose-limiting side effects will be maintained on their maximum tolerated dose. Once the maximal dose is established for each participant, they will complete 6 continuous weeks on this dose (maintenance period), followed by a 1-week washout. For study subjects unable to titrate up to 48 mg/day due to side effects, the 6 weeks of maintenance will start once they reduce the study drug back to the maximum well-tolerated dose. Adverse events will be monitored throughout the study and will be reported after drug initiation. Dose reductions, suspensions, and withdrawals due to adverse events will be recorded. ECG readings will be measured at screening, during week 2, during the first week of the maintenance period (whenever this is established to be, typically week 7 for subjects able to titrate up to 48 mg/day), immediately before washout (week 12 for those study subjects who are able to titrate up to 48 mg/day) and during week 13. Assessment of Columbia Suicide Severity Rating Scale and Epworth Sleepiness Scale scores will occur at screening and all clinic Visits. The Mini Mental (MMSE) Scale will be performed at screening and at the final on-treatment Visit (week 12). A video examination of the study subjects will be made at screening (right before initiation of the study drug), and after 6 weeks on AUSTEDO at a steady dose (right before drug cessation). Part III of the MDS-UPDRS will be performed at both of these Visits as well to screen for the appearance of drug-induced parkinsonism. Videos will be sent to raters blinded to treatment, Visit number and recording date.

Inclusion Criteria:

1. Study subjects with definite dystonia, as established by a movement disorder specialist.
2. Study subjects of any race and either gender, age 18 or more on the date the informed consent form (ICF) is signed and with the capacity to provide voluntary informed consent.
3. Study subjects able to read and understand English and the ICF and are willing to comply with all study procedures, treatment and follow-up.
4. Study subjects who are taking any central nervous system acting medications (e.g., benzodiazepines, antidepressants, hypnotics), including medications for the treatment of dystonia, will be on a stable regimen for at least 30 days prior to the screening Visit, and will willing to remain on the same dose for the duration of the study.
5. Female of child-bearing potential will not be pregnant and will be using an acceptable method of contraception.
6. Study subjects with an MMSE >24.

Exclusion Criteria:

1. Exposure to dopamine blockers prior to the onset of dystonia that could, in the investigator's opinion, have caused dystonia.
2. Study subjects with genetically-confirmed dopa-responsive dystonia.
3. Study subjects with a diagnosis of Parkinson's or an atypical parkinsonian syndrome.
4. Study subjects with a history of bipolar disorder or major depression, or the presence of active depression.
5. Study subjects with a history of a suicide attempt or suicidal ideations, as well as the presence of active suicidal ideation as detailed on the C-SSRS administered during Visit 1.
6. Study subjects with a history of schizophrenia or schizophrenia spectrum disorders.
7. Treatment with tetrabenazine, reserpine, valbenazine, a monoamino oxidase inhibitor, a-methyl-p-tyrosine, strong anticholinergic medications, metoclopramide, antipsychotics, dopamine agonists, levodopa, and/or stimulants within 30 days of screening.
8. Treatment with botulinum toxin less than 11 weeks prior to screening (Visit 1); subjects receiving injections sooner than every 12 weeks will be excluded if their next injection is scheduled farther than 6 days from screening.
9. Presence of a neurologic condition that could confound dystonia assessments.
10. Study subjects with a history of clinically relevant hepatic disease.
11. Study subjects with a history of renal insufficiency.
12. Any unstable medical illness.
13. A corrected QT (Bazett) interval of 450 (458) milliseconds in men or 460 (472) milliseconds in women on 12-lead ECG at screening, or a history of cardiac arrhythmias.
14. Study subjects participating in any drug or device clinical investigation concurrently or within 30 days prior to screening for this study.
15. Study subjects with a known hypersensitivity or contraindication to the study drug or its components.