Parkinson's disease and Parkinson's disease psychosis: a perspective on the challenges, treatments, and economic burden.

Parkinson's disease (PD) is a progressive neurodegenerative disease associated with a decrease in the neurotransmitter dopamine and characterized by the cardinal motor hallmarks of resting tremor, rigidity, bradykinesia/akinesia, and postural instability. Lesser-known features of PD revolve around nonmotor concerns including psychosis, dementia, sleep disturbances, autonomic dysfunction, and sensory abnormalities. Parkinson's disease psychosis (PDP) contributes significantly to morbidity, mortality, nursing home placement, and quality of life (QOL). PDP management suffers from a lack of safe, effective pharmacological agents and the opposing nature of atypical antipsychotics and dopaminergic therapies. Pimavanserin, the only atypical antipsychotic currently approved by the FDA for treating PDP-related hallucinations and delusions, has no appreciable affinity for dopaminergic receptors, and a controlled clinical study demonstrated its efficacy in treating PDP-associated hallucinations and delusions without affecting motor function. A recent analysis of all health resource utilization (HRU) and total costs attributable to PD and PDP found that mean 12-month HRU services per patient were 2.3 times higher and costs were 2.1 times higher in the PDP cases, while falls were 3.4 times higher and fractures 2.3 times higher, respectively. Products or services that prevent, delay, or lessen the severity of PDP may contribute to reduced healthcare system costs and improve the QOL of patients with PDP and of their caregivers.