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Parkinson’s Disease is a progressive neurodegenerative disorder in which the brain’s ability to produce dopamine, an essential neurotransmitter, is damaged, leading to symptoms including tremors, shaking, rigidity, and difficulty with movement and speech, and for some, significant cognitive and emotional effects as well. These symptoms generally advance and worsen over the course of a patient’s life.

Anyone can develop the disease, although it is more prevalent in men than in women and in whites than in individuals of other races. In most cases, symptoms emerge after age 60, but for about 5 percent of those who develop Parkinson’s, it begins before the age of 50. Parkinson’s itself is not fatal, although its symptoms often lead to life-threatening complications; these complications are the 14th-leading cause of death in the United States, according to the federal Centers for Disease Control and Prevention.

Parkinson’s has no cure, although medication and therapy can help individuals lessen the effects of some symptoms.


According to the National Institutes of Health, the primary symptoms of Parkinson’s Disease are:

  • Unintended, uncontrollable tremors or shaking in one or more limbs, which also occurs when the arm, leg, or hand is at rest.
  • Muscle contraction, stiffness, and rigidity, often for long stretches of time.
  • Slowed movements, also known as bradykinesia.
  • Impaired coordination and balance, increasing risk of falls and other injuries.

Other symptoms include impaired speech, constipation or urinary problems, difficulty chewing or swallowing, and skin problems. And for many patients, Parkinson’s Disease also brings depression, emotional changes, hallucinations, and major or mild neurocognitive symptoms.

It is important to note that one person’s experience of living with Parkinson’s—the severity and particular set of symptoms, the speed of the disease’s progression, and whether it brings cognitive or emotional concerns along with it—can vary in significant ways from another’s.

How does Parkinson’s Disease progress in its early stages?

The rate of Parkinson’s progression and accompanying symptoms can vary widely from patient to patient. Often, the first signs of Parkinson’s are mistaken for signs of normal aging, including sleep difficulty, constipation, and restless legs. (Rapid Eye Movement sleep behavior disorder, in which an individual reacts physically to their dreams, often occurs in people who are eventually diagnosed with Parkinson’s.)

Other symptoms may advance gradually and may include mild tremors, changes in gait, some difficulty with movement including smaller steps and reduced arm swinging, quieter speech, handwriting changes (typically, letters become smaller and less legible), and changes in affect—specifically, one’s face losing expression or animation. Often another person such as a partner, friend, relative, or primary-care physician notices changes before an individual is willing or able to do so. 

What are the cognitive and emotional symptoms of Parkinson’s Disease?

Some, but not all, individuals with Parkinson’s Disease will experience memory and attention problems, and difficulty remembering and completing tasks that could affect their daily routines. Some individuals with more severe cognitive symptoms including substantial memory loss may eventually be diagnosed with the condition known as Parkinson’s dementia.

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The etiology of Parkinson's is not well understood. In a Parkinson’s patient, nerve cells in the brain region known as the basal ganglia, which control movement, are impaired or die. Neurons in this region are relied upon to produce dopamine, an essential neurotransmitter. When their production is limited, a person experiences the movement challenges typical of Parkinson’s, which progress over time. Researchers do not know for sure what causes the neurons to begin to die off but now generally believe it is a combination of genetic and environmental factors, including exposure to toxins.

How is Parkinson’s Disease diagnosed?

There is no blood or laboratory test for Parkinson’s Disease. An individual who appears to be experiencing symptoms may see their doctor for referral to a neurologist who can conduct a neurological examination based on the Unified Parkinson’s Disease Rating Scale, which establishes baseline measures of core symptoms of the condition.

Parkinson’s symptoms are somewhat similar to other conditions including Lewy body dementia. One way a doctor can determine that a patient has Parkinson’s is by evaluating their response to medications commonly used to treat the disease. Magnetic resonance imaging (MRI) scans of the brain, a dopamine transporter (DaT) scan, or blood work may be prescribed either to confirm a diagnosis or to help rule out other medical conditions that may manifest with similar symptoms.

Does Parkinson’s Disease run in families?

Not typically. Genetics plays a role in Parkinson’s, as some specific genetic variants may cause it, but that does not necessarily mean those variants are inherited within families. However, some research suggests that early-onset forms of the disease—in which symptoms emerge before age 50—are more likely to be hereditary.


There is no cure for Parkinson’s Disease, although medication and therapy can help people find some relief from symptoms and ideally slow the progression of the condition. In addition to ameliorating symptoms of the disease, medications for Parkinson’s increase the level of dopamine in the brain and support other neurotransmitters that could help compensate for its absence.

What medications help to treat Parkinson’s?

The primary medication for Parkinson’s Disease is levodopa, which is converted to dopamine in the brain, enabling a patient to experience some relief from their symptoms. On its own, levodopa causes nausea, so it is combined with the drug carbidopa, which significantly lessens that side effect. Another primary side effect of levodopa is dyskinesia, or involuntary extraneous movements. (It’s a common misconception that dyskinesia is a symptom of Parkinson’s but it is instead a side effect of the drug.) Other side effects may include low blood pressure and restlessness.

Levodopa does not halt or slow the progression of Parkinson’s; it only addresses symptoms in the moment. Patients prescribed levodopa will generally take the drug for the rest of their lives.

Doctors may also prescribe medications such as amantadine and anticholinergics to directly address physical symptoms such as tremors, or to counteract dyskinesia brought on by levodopa.

What are dopamine agonists?

Doctors may prescribe drugs known as dopamine agonists instead of, or in conjunction with, the oft-prescribed drug levodopa. Dopamine agonists do not convert to dopamine but instead stimulate brain regions typically influenced by dopamine, in effect tricking the brain into believing the neurotransmitter is present. Levodopa generally has a stronger effect on Parkinson’s symptoms, but agonists have fewer side effects and are less likely to bring on dyskinesia.

The US National Institutes of Health/National Institute on Aging.
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition.
The Parkinson’s Foundation.
The Michael J. Fox Foundation for Parkinson's Research.
Last updated: 10/25/2023