Stress can cause all kinds of health problems. It can contribute to heart disease, diabetes, depression, insomnia and can make you more susceptible to viruses and bacterial infections. Recent research has also shown that stress may contribute to Parkinson's disease.
Parkinson's disease is a degenerative neurological disorder. It is the second most common neurodegenerative disease diagnosed in the United States; Alzheimer's disease is the most common. The average age at diagnosis 1s 60, however, it has been diagnosed in some children as young as 18. The most noticeable symptoms of Parkinson's disease are tremors, slowness of movement, balance problems and muscle rigidity. There are also less noticeable symptoms, such as cognitive impairment, memory problems, insomnia and mood disorders. It is a progressive disease, however, the rate of progression, as well as the range of symptoms, varies in each person.
Causes of Parkinson's disease
The cause of Parkinson's is not yet understood. Men are diagnosed more often than women and the risk of developing Parkinson's increases with age. Those with head injuries or who have been exposed to pesticides may be at a higher risk of developing the disease. Scientists believe that a combination of genetic and environmental factors interact to cause the disease, however, genes alone usually do not cause Parkinson's. Scientists do know that the disease results from the loss of cells in the brain, especially in the region of the brain called the substantia nigra.
Stress and Parkinson's disease
A study completed in 2010 at Northwestern University and published in the journal Nature shows that stress prematurely kill dopamine-producing neurons in the substantia nigra. According to the researchers, these neurons, in people under a great deal of stress, use a large amount of energy and produce molecules that are linked to aging, cellular dysfunction and death. As we age, we slowly lose these neurons, however, stress may quicken the process.
Stress has long been known to worsen symptoms of Parkinson's disease, especially tremors but the scientists involved in the study think the loss of these neurons may trigger Parkinson's disease in some people.
Fighting the stress effect
The medication isradipine, currently approved by the FDA for treating high blood pressure, may help reduce the effects of stress on the dopamine-producing neurons. Researchers are conducting clinical trials to find out whether the medication can be used safely in patients with Parkinson's disease and whether it will be well tolerated.
According to D. James Surmeier, lead author of the study, "By lowering their metabolic stress level, we should be able to make dopamine-releasing neurons live longer and delay the onset of Parkinson's disease. For individuals diagnosed with Parkinson's disease, the hope is that this drug can slow disease progression, giving symptomatic therapies a broader window in which to work." 
"Oxidant Stress Evoked by Pacemaking in Dopaminergic Neurons is Attenuated by DJ-1," Jaime N. Guzman et al, 2010, Nov, 10, Nature
"Parkinson's Diagnosis Questions," Date Unknown, Staff Writer, Michael J. Fox Foundation for Parkinson's Research
 "Stress Takes its Toll in Parkinson's Disease, 2010, Nov. 11, Staff Writer, ScienceDaily