Deutetrabenazine Treatment for Tardive Dyskinesia in Intellectual/Developmental Disabilities

The primary goal of this study is to investigate the efficacy of deutetrabenazine treatment of TD in this previously untreated patient population. Compare movement disorder deutetrabenazine treatment response in persons with IDD to response seen in patients without IDD treated with deutetrabenazine in other treatment settings (per literature review). Compare global deutetrabenazine treatment response with validated instruments. In addition, we plan to: * Assess the safety of deutetrabenazine in the treatment of TD in persons with IDD. * Assess change in Activities of Daily Living (ADLs) in persons with IDD and TD treated with deutetrabenazine, utilizing a validated ADL instrument. * Assess change in Quality of Life (QOL) in persons with IDD and TD treated with deutetrabenazine, utilizing a validated QOL instrument. * Assess caregiver burden with a validated caregiver burden instrument. In this study, 25 participants with IDD and TD will undergo Deutetrabenazine treatment for 24 weeks. The participants will be seen for a total of 5 visits: at baseline, and at follow up visits at 3 weeks, 6 weeks, 12 weeks, and 24 weeks. This study does not include a comparison group. Therefore, researchers will compare the response of the study participants to deutetrabenazine treatment with those from a previous reported work that resulted in the FDA approval of this medication. This will be an open-label, Phase 4 study.