Psychotic symptoms in Parkinson’s disease: Etiology, prevalence and treatment

Abstract

Introduction. Parkinson?s disease is the second most common neurodegenerative disease with as many as 50-70% of patients experiencing psychotic symptoms during the course of the illness. Our aim was to provide an evidence-based review on the etiology, prevalence and management of psychotic symptoms in Parkinson?s disease. Material and Methods. We used references from the ?Medline? database published from 1999 to 2019. Results. The most common psychotic symptoms in Parkinson?s disease are visual hallucinations, which occur in 25-30% of patients, acoustic hallucinations in about 20%, and delusions in around 5% of these patients. The etiology of psychotic symptoms is not fully clarified, but researchers suggest a complex interrelationship of factors associated with the disease itself and the factors associated with antiparkinsonian medications. After exclusion of other etiologic causes of psychotic symptoms, it is necessary to revise the type and dose of antiparkinsonian drugs. Although pimavanserin has recently been approved by the United States Food and Drug Administration, the current treatment of choice for psychotic symptoms in Parkinson?s disease is still quetiapine. Only patients who do not tolerate or do not respond to quetiapine are treated with clozapine, which has been proven more effective, but with significant side effects. Conclusion. Timely diagnosis and adequate treatment of psychotic symptoms in Parkinson?s disease are essential, because they dramatically affect the quality of life of patients and their families. Therefore, it is necessary to establish more effective tools for screening and treatment of psychotic symptoms in Parkinson?s disease.