Quality of life of Parkinson's disease (PD) patients is adversely affected by impairment of physical and psychological functions. Antiparkinson's drugs and disease progression may contribute to the development of secondary symptoms (motor fluctuations, dyskinesias, postural abnormalities, sleep disorders, psychiatric complaints, autonomic disturbances, etc) that may require additional medication to alleviate.

Determining local incidence of PD related psychosis will provide foresight into planning of service needs in our local cohort of patients.

The aim of this study is to determine the local incidence of psychosis in PD.

This is a retrospective cohort study looking at only PD cases diagnosed between January 2006 and December 2007 and recruited into the movement disorder database by the National Neuroscience Institute. The study period is defined as date of diagnosis through to December 2013, where the subjects undergo a variety of scaled assessments conducted during routine outpatient consultations. During the defined study period, a diagnosis of PD related psychosis will be defined as a score of 2 or more on the Thought Disorder subscale of the Unified Parkinson's Disease Rating Scale.

The proportion of patients in the study population who developed psychotic symptoms during the study period is comparable to existing literature.

This study allows us to better understand the local incidence of psychosis in PD patients. It provides groundwork for looking at whether regular screening for psychiatric symptoms in this patient cohort would be beneficial in the long term management of PD patients.