Treatment of Parkinson’s Disease Psychosis

Abstract

Psychotic symptoms in Parkinson’s disease are relatively common and include hallucinations, illusions, and delusions. Psychosis is a major cause of disability and is one of the most distressing symptoms for both patients and caregivers. The management of psychosis is often complex and challenging and involves determining the degree and severity of psychotic symptoms and whether intervention is required. In this review, the authors describe the phenomenology and risk factors of Parkinson’s disease psychosis (PDP) and current evidence-based treatment options. In randomized, double-blind, placebo-controlled trials, pimavanserin was found to be effective and well-tolerated in PDP but its onset of benefit takes 4–6 weeks. Present reviews of evidence-based medicine suggest that low doses of clozapine can provide benefit without worsening PD motor symptoms. While quetiapine is frequently used, its efficacy is not supported by randomized, double-blind, placebo-controlled trials. Clozapine and pimavanserin have proven efficacy in the treatment of PDP, without impairing motor function. Therefore, these agents should be considered first-line treatment of PDP at this time. Although quetiapine did not show efficacy in PDP, many PD experts use it as it does not worsen motor function and lacks the blood monitoring requirement of clozapine.