The National Headache Foundation estimates that US businesses lose $50 billion each year because of absenteeism, reduced employee productivity, and medical expenses caused by headaches. (JD Bartleson, Treatment of Migraine Headaches, Mayo Clin. Proc. 1999; 74; 702-708). In the U.S., more than 30 million people suffer from migraines, according to a 2001 report from the Health's National Institute of Neurological Disorders and Stroke. It is the 12th most disabling disorder in the US. Neurologists agree that safer and more effective prophylactic agents represent the most critical unmet need in the treatment of both episodic and chronic migraine.

Parkinson's Disease is one of the most common neurologic disorders, affecting approximately 1% of individuals older than 60 years and causing progressive disability that can be slowed, but not halted, by treatment. Despite extensive research in the area of PD, the precise pathogenesis remains largely unknown. Parkinson's Disease is characterized by motor and nonmotor (cognitive and limbic) deficits. The economic burden of Parkinson's disease is at least $14.4 billion a year in the United States, and the prevalence of Parkinson's will more than double by the year 2040.