“Parkinson's disease is a brain disorder that leads to tremors, difficulty walking and coordinating.” (1). The disease occurs when nerve cells in the brain are destroyed and slow the production of dopamine; without dopamine the brain cannot transmit messages to the rest of the body. This is why the tremors and lack of coordination and movement begin as the brain cannot tell the body what to do correctly. There are no exact causes of the disease; it is considered a multifactorial trait. A multifactorial trait “may be determined by two or more factors; often multiple genes interact with each other or with the environment” (5). It is also believed that some medications, both prescribed and outpatient, can cause the symptoms of Parkinson's disease. These symptoms include slower automatic movements such as blinking, difficulty walking, swallowing and coordination; as well as visible tremors and muscle pain. Those tested, most commonly in older adults, have difficulty completing movements and are somewhat jerky in the movements tested. There is no cure for Parkinson's disease. Doctors and therapists try to control symptoms with medications, but they also recommend exercises that release dopamine to counteract some effects. In some severe cases, surgery is used to destroy the brain tissue that causes the disease, but this only happens on rare occasions. Along with all the physical problems associated with this disorder, mental problems also occur. According to one doctor, “at least 40% of patients with Parkinson's disease suffer from a severe attack of depression.” (2) In most cases, however, the patient's depression comes in short bursts and for the most part does not last long. Physical impairments are immediately seen and are the “distinctive characteristics”… at the center of the article……d, Mood and Behavior” Princetonwellbeing.com. July 25, 2000. April 1, 2014(4) Findley, Leslie. “The economic impact of Parkinson's disease” elsevier.com 2007. 1 April 2014.(5) Rosenberg, Leon E. Human genes and genomes. New York: Elsevier, 2012. Print. April 4, 2014.(6) "Understanding Parkinson's." Parkinson's Disease Foundation. Np, 2014. Web. 6 April 2014. .(7) Gwinn, Katrina. "Genetics and Parkinson's disease: what have we learned?" Parkinson's Disease Foundation. Np, 2009. Web. 6 April 2014..(8) Tanner, Caroline M. "Environmental Factors and Parkinson's: What Have We Learned?" Parkinson's Disease Foundation. Np, 2011. Web. 6 April 2014..(9) OMIM. Johns Hopkins University, 2014. Web. 9 April. 2014..