The purpose of this research study is to see if tetrabenazine, which is commonly used to
treat Huntington's Disease (HD), reduces the problems of impulsivity that are common in
patients with HD. Investigators will also see how the medicine affects aspects of thinking
This study is an open-label assessment of behavioral symptoms including depression,
impulsivity, and suicidal ideations in patients prior to, and after, taking a stable dose of
TBZ for Huntington's disease. All subjects will be evaluated with tests of depression (Beck
Depression Scale), impulsivity (QUIP, BIS-11, and computerized impulsivity scales), and
suicidal ideation (Columbia Suicide Scale) as a safety measure before they actually start
taking TBZ. Since there is a significant lack of awareness of emotional and cognitive
symptoms (anosagnosia) in patients with HD, collateral sources will be asked to fill out
similar questionnaires based on their knowledge and observation of the patient. Patients and
collaterals will be asked to return to the clinic for an identical evaluation plus adverse
events, after they have been on a stable dose of TBZ for 4 weeks, which would be 8 ± 1 week
after initiating TBZ. Patients will be titrated over 3-5 weeks to best dose as determined by
the investigator, up to a maximum of 75 mg/day. As patients are titrating, there will be
several telephone contacts conducted. The initial dose will be 12.5 mg BID. Best dose will be
largely determined by adverse events and subjective efficacy. Determination of best dose will
include two scheduled phone calls and others as needed. Other medications will remain stable
- For HUntington's Disease (HD) patients only--Definite HD as indicated by positive gene
testing or typical symptoms in the context of family history of HD.
- A moderate degree of impulsivity as measured by the Barrat Impulsivity Scale (BIS).
- Must be symptomatic in the opinion of the investigator. Standard clinical criteria for
symptomatic HD will be employed, any motor signs c/w HD, usually chorea.
- Patient is cognitively alert and able to answer/understand.
- Patient requires the assistance of another person to walk, or is non-ambulatory.
- Patient is severely impaired cognitively.
- Patients taking neuroleptic (dopamine blocking) medications within the past 14 days.
- patient is actively suicidal, has untreated or inadequately treated depression, has
impaired hepatic function, is taking MAO inhibitors or is taking reserpine or has been
off of reserpine for less than 20 days