Treating psychosis in people with Parkinson's disease.

Psychotic symptoms in Parkinson's disease are common and are comprised of hallucinations and delusions. Psychosis is a major cause of disability in PD and is primarily due to an interaction with PD medication. The decision to treat psychosis is determined by the severity of the symptoms, impact on quality of life and tolerance for the treatment. Initial management involves a reduction in non-PD psychoactive medications and/or modification of PD medications. Pharmacotherapy is primarily limited to atypical antipsychotics and pimavanserin. This review will focus on the phenomenology of Parkinson's disease psychosis and its management. Pimavanserin is the only Food and Drug Administration medication approved for the treatment of PDP. Among the antipsychotics, only clozapine and pimavanserin demonstrated efficacy in the treatment of PDP. Despite lack of evidence for efficacy in PDP, quetiapine is commonly used because it does not worsen motor function and lacks the blood monitoring requirement of clozapine. Pimavanserin is the first-line treatment for mild psychotic symptoms that do not require a rapid response and quetiapine and clozapine for psychosis that requires improvement in a short period of time. Antipsychotics used to treat PDP should demonstrate safety, motor tolerability and efficacy over time.