Multi-centre UK Study of the Acetylcholinesterase Inhibitor Donepezil in Early Dementia Associated With Parkinson's Disease

To demonstrate the superiority of donepezil over placebo in improving cognitive function, neuropsychiatric burden and functional ability in people with Parkinson's disease and mild dementia after 24 months of treatment. To demonstrate the superiority of donepezil over placebo in improving patient and carer quality of life and to establish the cost-effectiveness of donepezil. To determine the instrument most suitable for evaluating change in cognition in people with Parkinson's disease and mild dementia.