About Parkinson’s disease (PD)

Parkinson’s disease, which is commonly referred to as PD or just ‘Parkinson's’, was named after a London doctor called James Parkinson, who first described the symptoms of the disease in 1817.

PD is a condition of the nervous system (i.e., a neurological condition) that is characterised by problems with body movements, although other non-movement symptoms can also occur. Body movements are controlled by nerve cells in the brain that pass messages to one another. These messages are sent using chemicals (neurotransmitters), which pass between the nerve cells and, in healthy people, the messages are carried smoothly (see Figure 1).

One important neurotransmitter that is involved in controlling body movements is called dopamine. In people with PD, there is a lack of dopamine in the brain, and therefore the relay of messages is disturbed, and this creates problems with the control of movement.

The symptoms of PD often appear gradually, usually on one side of the body first, and slowly progress over time. The main physical symptoms of PD are slowness of movement, stiffness, and sometimes tremor and loss of balance, although the type and severity of symptoms vary from person to person. Different symptoms may appear as PD progresses.

PD is globally distributed, affecting all cultures and races, with an estimated worldwide prevalence of 6.3 million people. More than 1 in 10 people with PD are diagnosed before the age of 50 years.

Although, at present, there is no cure for PD, the symptoms can generally be treated effectively by using a variety of medications. These medications help each person carry on with everyday life and people with PD can continue to enjoy a good quality of life for many years. Treatments for PD are described later in this Guide (see Section 2, ‘Managing Parkinson’s disease’ ).