What Causes Parkinson's Disease

Parkinson's disease is caused by a loss of nerve cells in a part of the brain called the substantia nigra, which normally produces a chemical called dopamine — a messenger helping to control and coordinate body movement. As these nerve cells die or become damaged, dopamine levels fall, meaning the brain's movement-control centre can no longer work as well as normal, causing movements to become slow and abnormal. This loss happens gradually, and symptoms usually only begin once around half of the nerve cell activity in this brain region has already been lost.

It isn't known exactly why this loss of nerve cells occurs, though most experts believe a combination of genetic and environmental factors is responsible. Certain genetic changes can raise the risk, and while Parkinson's can occasionally run in families through inherited faulty genes, this is rare. Some researchers suggest environmental factors — such as pesticides, herbicides, or traffic and industrial pollution — may also play a role, though the evidence remains inconclusive.

Other Causes of Parkinsonism

"Parkinsonism" is the broader term for the combination of tremor, muscle rigidity and slow movement. Parkinson's disease is the most common cause, but rarer types exist with an identifiable cause, including medication-induced parkinsonism (which usually improves once the responsible medicine is stopped), other progressive brain conditions, and cerebrovascular disease, where a series of small strokes damage several parts of the brain.

Getting a Diagnosis

There's no single test that can conclusively confirm Parkinson's disease — a GP will base an initial assessment on your symptoms, medical history, and simple physical or mental tasks, such as walking or moving around. Since symptoms are usually mild early on, it can be difficult for a GP to be certain in the early stages. If Parkinson's is suspected, you'll be referred to a specialist, usually a neurologist or a geriatrician, who may ask you to complete physical exercises to assess movement, and occasionally arrange a specialist brain scan (such as a SPECT scan) to rule out other causes.

Receiving a diagnosis can be emotionally difficult, and it's important to have support from family and your care team while you come to terms with the news. Parkinson's UK, the main UK charity for the condition, offers a free helpline (0808 800 0303), local support groups, and an online community forum for anyone affected.

Overview of Treatment

There's currently no cure for Parkinson's disease, but treatments are available to relieve symptoms and support quality of life, including supportive therapies, medicine, and, for some people, surgery. In the early stages, when symptoms are usually mild, you may not need treatment straight away, though regular specialist appointments help monitor how the condition is progressing. A care plan, agreed with your healthcare team and family or carers, outlines your current and likely future needs, and should be reviewed regularly.

Supportive Therapies

Physiotherapy can help relieve muscle stiffness and joint pain, and improve walking, flexibility and fitness. Occupational therapy helps identify difficulties with everyday tasks and find practical solutions, including making the home safer and better suited to your needs. Speech and language therapy can help with speech and swallowing difficulties, sometimes using assistive technology. Dietary changes — such as increasing fibre and fluids for constipation, or adjusting salt intake and meal patterns for low blood pressure — may also be recommended by a dietitian.

Medicines

Three main types of medicine are commonly used. Levodopa, which the brain converts into dopamine, is the medicine most people eventually need, and is usually combined with another medicine to reduce side effects such as nausea, tiredness or dizziness — though its effects can become less consistent over time, sometimes causing involuntary jerky movements or "on-off" fluctuations between good and poor movement control. Dopamine agonists act as a milder substitute for dopamine, and can cause similar side effects, alongside a risk of hallucinations, confusion, or — particularly at higher doses — compulsive behaviours such as gambling or overspending, which family members should watch for and report to the care team. Monoamine oxidase-B (MAO-B) inhibitors, such as selegiline and rasagiline, offer a milder alternative for early Parkinson's, and are generally well tolerated.

Catechol-O-methyltransferase (COMT) inhibitors are used in later-stage Parkinson's alongside levodopa, and non-oral treatments — including injected apomorphine, or continuous pump-delivered medicines like co-careldopa — may be considered for more severe cases where tablets alone aren't providing good control.

Surgery and Additional Symptoms

Deep brain stimulation, involving a surgically implanted device that sends electrical signals to specific brain areas, can ease symptoms for some people, though it doesn't cure the condition and isn't suitable for everyone — it's available at specialist centres, and your specialist will discuss the risks and benefits. Additional symptoms such as depression, sleep problems, sexual difficulties, excessive sweating, swallowing problems, drooling, incontinence, or dementia can often be treated individually alongside core Parkinson's care.

Clinical trials continue to advance treatment options, and taking part is entirely optional, with no effect on your ongoing care if you choose not to, or later decide to withdraw. Complementary therapies are popular with some people, but there's no clinical evidence they control Parkinson's symptoms directly, and some — such as St John's wort — can interact unpredictably with prescribed medicines, so it's always worth checking with your care team first.

Staying Well

Regular exercise can help relieve muscle stiffness, improve mood, and reduce stress — more vigorous activities like team sports, cycling or running may suit those newly diagnosed or with mild symptoms, while gentler options like walking or stretching may suit more advanced symptoms. A balanced diet, alongside a yearly flu vaccine (recommended for anyone with a long-term condition) and COVID-19 vaccination if eligible, also supports overall health.

Relationships and Support

A diagnosis like Parkinson's can put a strain on relationships, and dealing with worsening symptoms can bring frustration or low mood for both the person affected and those close to them. Being open about how you're feeling, and letting family and friends know what would help, can ease this. A GP, specialist Parkinson's nurse, counsellor, or psychologist can offer support, and many people find real value in connecting with others living with the condition, whether through a local support group or online. Parkinson's UK offers a free helpline (0808 800 0303) and an online community forum for anyone affected.

Work, Finances and Driving

A Parkinson's diagnosis doesn't necessarily mean stopping work — many people continue working for years afterwards. If you do need to reduce your hours or stop working, various financial support options may be available, including Statutory Sick Pay, Employment and Support Allowance, Personal Independence Payment, Attendance Allowance, or Carer's Allowance if you're supporting someone else with the condition, depending on your circumstances.

You must inform the DVLA and your car insurer if you're diagnosed with Parkinson's — this doesn't necessarily mean you'll have to stop driving, but you'll need to complete a form about your condition, which the DVLA uses to assess your fitness to drive.

Complex Parkinson's and Palliative Care

Complex Parkinson's disease describes the stage where treatment can no longer consistently control symptoms, or where disabling involuntary movements develop — a specialist can often still help by adjusting medicines at this stage. As the condition progresses, you'll be encouraged to discuss your future care preferences with your healthcare team, known as palliative care — this focuses on relieving pain and other distressing symptoms, and providing psychological, social and spiritual support for you and your family, whether at home, in a hospice, care home, or hospital. It's worth talking to your family and care team in advance about where you'd like to be cared for and what kind of support you'd want.