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What is the Cause of Parkinson's disease?



"I need to know where the disease is coming from and what causes it - why me?"


  • Parkinson's disease primarily affects the part of the brain that is responsible for the control of movement. The small part that is damaged (degenerates) is called the substantia nigra, located deep at the base of the brain. As PD progresses, other areas of the brain also degenerate.

  • The pigmented nerve cells in the substatia nigra manufacture dopamine, that functions as a chemical messenger, or 'neurotransmitter'. Dopamine is responsible for helping to send messages between cells within the brain that normally ensures smooth, controlled body movements.

  • The low dopamine levels in PD result in the typical symptoms of slowness of movement, muscular stiffness, tremor and poor balance. Everyday movements like walking, getting up from a chair, writing and doing up buttons becomes more difficult.

  • Normal ageing reduces dopamine production, but the reduction in dopamine levels is much more marked in PD. Over 80 per cent of dopamine production has to be lost before symptoms and signs of PD begin to show. Old age alone is not sufficient to cause PD. 

  • Despite much research, no one knows what causes the brain damage that results in PD. Genetic factors play a role and unidentified environmental toxins may be important. It is most likely that PD is caused by a combination of several interacting factors that exacerbate the slow age-related degeneration in dopamine production. 

  • PD is not caused by infection, poor diet, or by stress or anxiety.

  • Some people may have many of the features of Parkinson's disease, but the cause is another medical condition. This is termed 'Parkinsonism'. Stroke disease, dementia with Lewy bodies and the side effects of some drugs are common causes.

  • There are also some less common neurological conditions that may mimic PD, but have additional signs and symptoms and so are called 'Parkinson's Plus Syndromes'. These include Multiple System Atrophy (MSA) and Progressive Supranuclear Palsy (PSP).

  • Overall, PD is one of the most common disabling neurological conditions in older people, though it can also develop in younger adults. About one person in a hundred aged over 65 will have PD.

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Further Information

Your doctor, or specialist nursing staff should be able to answer your questions about the nature and causes of Parkinson's disease.

The Parkinson's Disease Society (telephone 020 7931 8080) can also provide information http://www.parkinsons.org.uk

Useful books include:

'Understanding Parkinson's Disease', by J Pearce and Tony Smith, published in 2000 by Family Doctors Publications, London. ISBN 1898 20 5868

Useful Websites are:

PD Internet Resources Site


US National Organisation of Parkinson's disease causes of illness 



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This site has been established for the dissemination of information. While every effort is made to ensure that information on this site is accurate and current we accept no liability for any omissions or inaccuracies that may have crept in. If in any doubt please contact your doctor for further advice.

Last Modified 13 August 2004
Maintained by Matthew Harris