Psychosis in Parkinson's disease

Abstract

Psychotic symptoms are common in Parkinson's disease (PD), affecting nearly 50% of all patients over the course of the disease. The form and severity of psychotic symptoms varies, ranging from nondistressing hallucinations in any sensory modality to complex visual hallucinations and delusions. PD patients with psychosis often come to psychiatric attention when serious behavioral disturbances develop. Anti-parkinsonian therapies are a primary factor in the development of psychosis, but PD-related psychoses are not exclusively drug-induced. Nondopaminergic factors are also relevant, including cognitive impairment, mood disorders, visual acuity, sleep disturbances, other medication effects, and delirium. Management involves addressing multiple issues, including modifiable risk factors. Because psychosis impacts patient function and caregiver burden, the clinical care of PD patients should entail routine monitoring for psychosis, re-assessment of the therapeutic regimen, and attention to any remediable risk factors. Antipsychotic medications are indicated when symptoms are distressing or disruptive, but their use requires consideration of potential adverse motor and cognitive side effects.