Risks and Triggers of Psychosis in Parkinson Disease

Psychosis is a common non-motor complication in Parkinson disease, and affects the quality of life of patients and their care-givers. This psychosis is caused by intrinsic (pathological and genetic) and extrinsic factors. Pathological factors include the severity of Lewy body pathology, degeneration of cholinergic neurons and overstimulation of serotonin receptors. Genetic factors include apolipoprotein e4, cholecystokinin genotyping, and glucocerebrosidase mutations. Extrinsic factors that trigger psychosis include systemic inflammation and medication of risky drugs. To prevent such psychosis, it is important to examine systemic infection, cease high-risk drugs, and then consider prescription of anti-psychotic drugs. This review is to discuss pathogenesis and therapeutic strategy of psychosis in Parkinson disease.