Huntington's disease (HD) is autosomal dominant neurodegenerative disease, starting in average (with high variability) in the fourth decade. The disease progression is classically characterized by a cognitive deterioration (cortical-frontal dementia), motor disorders (associating chorea, dystonia and bradykinesia), psychiatric disturbances (combining depression and irritability) and metabolic disorder (cachexia). The disease is fatal within 15 to 20 years in most patients. HD has no cure. Neuroleptics are the main drug used and the only to demonstrate its efficacy on chorea in clinical trials. But neuroleptics have also beneficial and adverse effects on other disease characteristics (motor, psychiatric, cognitive or metabolic). Their profile between beneficial and adverse effects could be different according the neuroleptics and their classification. The aim of this study is to compare beneficial and adverse effects of 3 different neuroleptics in HD.

We proposed a randomized controlled trial, including 180 patients, in 3 groups: Olanzapine, Tetrabenazine and Tiapride, followed during 12 months. These treatments have been selected according their profile and their frequency of use.

The principal criteria is the Independence scale, one of the functional scales of the Unified Huntington's Disease Rating Scale, the only validated scale in HD.

Secondary criteria will assess motor,functional, psychiatric and cognitive functions, metabolic parameters, tolerance and cost.

Inclusion Criteria:

1. Symptomatic disease with motor, behavioural and/or psychiatric disorder required medical treatment.
2. HD diagnosed with abnormal number of CAG repeats: 38 ≤ nucleotide expansion (CAG) (amendment n°5 suppressed the limit ≤ 48)
3. Neuroleptic Prescription required.
4. Age ≥ 18 (amendment n°5 suppressed the limit ≤ 65 years old)
5. Patient gave its written consent
6. Realization of medical examination and a Electroencephalogram

Exclusion Criteria:

1. Severe cognitive impairment or neuropsychiatric troubles.
2. Existing diabetes.
3. Neuroleptic prescription forbidden according to the neurologist decision.
4. Current participation to another clinical trial.
5. No drug compliance to previous treatment.
6. No national health insurance affiliation