Parkinson's disease is the fourth most common neurological condition in the UK behind stroke, all forms of dementia and epilepsy. However, in terms of progressive neurodegenerative diseases, it is second only to Alzheimer's disease.

In the UK, PD affects between 100 and 180 people per 100,000 population and each year there are between four and 20 new cases per 100,000 populating (region dependent), with more males affected then females and increasing prevalence with age. On average, there will be five to eight people on PD medication in every community pharmacy.

PD is rare below the age of 50 years €“ such cases are known as juvenile PD and account for only five per cent of all PD cases €“ but it affects one per cent of the population over 65 years, rising to two per cent in people over 80 years. Of note, 50 to 80 per cent of people with PD may develop Parkinson's disease dementia (PDD), although this seems more related to increasing age than PD itself.