RATIONALE: The wake-promoting agent modafinil selectively improves 
neuropsychological task performance in healthy volunteers, in adults with 
attention deficit hyperactivity disorder (ADHD) and in schizophrenia. We 
examined whether modafinil induced similar effects in individuals with 
Huntington's disease (HD).
MATERIALS AND METHODS: Twenty patients with genetically proven, mild HD 
participated in a double-blind, randomised, placebo-controlled cross-over study 
using a single 200 mg dose of modafinil. Patients undertook a battery of 
neuropsychological tests including measures of cognition and mood.
RESULTS: Modafinil increased alertness as indexed by visual analogue scales. 
Modafinil did not elicit any significant improvements in cognitive function or 
mood. Modafinil had a deleterious effect on visual recognition and working 
memory.
CONCLUSIONS: Two hundred milligrams acute modafinil administration did improve 
alertness but did not improve cognition or mood in patients with mild HD. A 
multiple dose, chronic administration study is needed before the potential 
clinical utility of modafinil in HD is discounted.