Psychosis in Parkinson’s disease

Opinion statementPsychotic symptoms are common and can be a major therapeutic challenge in patients with Parkinson’s disease (PD). PD-related psychosis is usually characterized by visual hallucinations or delusions and is most often induced by antiparkinsonian medications. However, other medical conditions, psychoactive medications, sleep disturbances, mood disorders, and cognitive impairments are relevant risk factors. Patients with PD should be continually monitored for factors that can trigger the development of psychotic symptoms, including minor symptoms. This includes ongoing critical re-evaluation of the therapeutic regimen, with adjustments as indicated to optimize function across motor, cognitive, and psychiatric domains. Treatment strategies to reduce psychotic symptoms are determined by the clinical picture. “Benign” symptoms may require only education and reassurance. Antipsychotic medications are required for disabling symptoms and emergency hospitalization may be required for agitation that affects the safety of the patient or others. Medication management is often complex and includes elimination or reduction of antiparkinsonian agents (although this can compromise motor function), management of medical comorbidities, and use of atypical antipsychotics. Clozapine and quetiapine are regarded as the most safe and effective atypical neuroleptics in PD patients. Cholinesterase inhibitors can enhance cognition and may reduce psychotic symptoms.