Deutetrabenazine Treatment for Tardive Dyskinesia in Intellectual/Developmental Disabilities

Participant Inclusion Criteria: * Diagnosis of IDD (IQ \< 70; social/adaptive dysfunction, onset \< age 22) as per DSM-5 * Clinical diagnosis of Tardive Dyskinesia (TD) per DSM-5 for at least 3 months before study inclusion (presence of movement disorder for at least 3 months, in absence of previous formal diagnosis of TD). * Eligible to receive deutetrabenazine, according to current product labeling Stable doses of all psychotropic medications for minimum of three months before study inclusion * Willing to remain on stable doses of all psychotropics for 24 weeks of study. If female of childbearing age, practicing acceptable form of birth control throughout study duration. * Subject able to comply with scheduled visits and assessments * Consent of subject, or legally authorized representative to study protocol. Caregiver Inclusion Criteria: * Able to understand and answer questionnaires * Able to comply with scheduled visits * Ability to be primary Caregiver for 24 weeks of study Participant Exclusion Criteria: * Previous treatment with a VMAT2 inhibitor (tetrabenazine, valbenazine, or deutetrabenazine). * Treatment with any investigational drug in the 30 days prior to study entry. * Currently taking a strong CYP2D6 inhibitor such as fluoxetine, paroxetine, quinidine, bupropion. Current treatment with strong anticholinergic agents, monoamine oxidase inhibitors, metoclopramide, dopamine agonists, L-DOPA, or stimulants within past 30 days, or botulinum toxin within the past 3 months. * Any unstable medical condition in the 60 days prior to study entry. * Pregnant or breast-feeding * Current or recent hepatic impairment * History of neuroleptic malignant syndrome * History of long QTc on electrocardiogram, bundle branch block (BBB), atrioventricular block, serious cardiac arrhythmia, or heart failure. QTc on EKG \> 450 msec (Fredericia formula) on EKG within 3 months prior to study entry. * History of substance abuse or dependence in the 3 months prior to study entry. * Significant risk of suicide or dangerous aggression to others at time of or 3 months prior to study entry. * Inability to take study medications Caregiver Exclusion Criteria: * Unable to complete questionnaires * Unable to comply with scheduled visits * Will not be a primary Caregiver for the 24 weeks of the study