In each jurisdiction, the investigators will assemble a study cohort that includes all patients with a new diagnosis of Parkinson's disease or a first-ever prescription of an antiparkinsonian drug between January 1, 1990 (or 1 year after site-specific data is available, whichever is later) and June 30, 2012. Patients will be followed from the date of study cohort entry until the occurrence of either study endpoint (defined below) or censoring due to death, departure from the database, loss of continuous health plan or drug plan enrolment, entry into a long-term care facility, or the end of the study period (or the last date of data availability at that site), whichever occurs first. Data from Alberta, Ontario, and Nova Scotia will be restricted to patients aged 66 years and older as prescription data are not available for younger patients.