Depression may raise the risk of developing Parkinson's disease, according to a new study.


Researchers from Taipei Veterans General Hospital in Taiwan found that people with depression have a tripled risk of developing Parkinson's disease over a 10-year period compared to those without depression.


However, the study only showed an association, and does not prove that depression causes Parkinson's disease, researchers cautioned. Parkinson's is a chronic condition[1] that involves the loss of dopamine-producing brain cells, and has symptoms of movement problems and tremors.


"Many questions remain, including whether depression is an early symptom of Parkinson's disease[2] rather than an independent risk factor for the disease," study researcher Albert C. Yang, M.D., Ph.D., said in a statement.


The study, published in the journal Neurology[3] , is based on 10 years' worth of data from 4,634 people with depression and 18,544 people without depression. Researchers found that having depression raised the risk of developing Parkinson's disease over the study period by 3.24 times.


In addition, they found that both age and difficult-to-treat depression were independent risk factors for Parkinson's disease.


Depression and Parkinson's have long been known to be intertwined, with the National Institutes of Health saying that symptoms of one condition can make symptoms of the other condition worse, and vice versa. The NIH explained[4] :


For example, people with both illnesses tend to have more movement problems and greater levels of anxiety than those who have just depression or Parkinson's disease. Compared with people who are depressed but do not have Parkinson's, people who have both illnesses may have lower rates of sadness and guilt, but greater problems with concentration.


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  • Michael J. Fox


    Fox, known for his roles in "Spin City" and the "Back to the Future" trilogy, was <a href="https://www.michaeljfox.org/foundation/michael-story.html" target="_hplink">diagnosed with Parkinson's disease</a> at age 30 in 1991, according to his foundation's website. However, he didn't share his condition publicly until 1998, and he officially retired from "Spin City" in 2000.

    That same year, Fox launched <a href="https://www.michaeljfox.org" target="_hplink">The Michael J. Fox Foundation</a> for Parkinson's Research, which is dedicated to raising awareness and funding.




  • Muhammad Ali


    The boxing champion first <a href="http://www.guardian.co.uk/lifeandstyle/2009/mar/20/parkinsons-disease-muhammad-ali" target="_hplink">started experiencing symptoms</a> of Parkinson's shortly after he retired from the sport in 1981, but <em>The Guardian</em> reported that he wasn't officially diagnosed until 1984. By that time, he was already <a href="http://www.guardian.co.uk/lifeandstyle/2009/mar/20/parkinsons-disease-muhammad-ali" target="_hplink">experiencing symptoms</a> of tremors, slow movement and slurred speech, according to <em>The Guardian</em>.

    The Associated Press reported that today, Ali, now 70, is largely left <a href="http://seattletimes.nwsource.com/html/othersports/2017257069_ali17.html" target="_hplink">unable to speak</a>, save for several whispers in the mornings.

    "The <a href="http://seattletimes.nwsource.com/html/othersports/2017257069_ali17.html" target="_hplink">Parkinson's has affected him</a> a lot, one of [the] things he has is a lot of difficulty speaking," Dr. Abraham Lieberman, director of the Muhammad Ali Parkinson Center in Phoenix, told the Associated Press. "But he's never downbeat about it ... He's a tremendous inspiration to everyone."




  • Janet Reno


    The former U.S. Attorney General -- and the first woman to hold that position -- announced her <a href="http://www.nytimes.com/1995/11/17/us/reno-discloses-diagnosis-of-parkinson-s-disease.html" target="_hplink">diagnosis of Parkinson's in 1995</a>, the <em>New York Times</em> reported. The first sign for her was uncontrollable shaking of her left hand.

    "Her <a href="https://ufandshands.org/news/2011/former-attorney-general-reno-helps-uf-open-center-movement-disorders-and-neurorestoration" target="_hplink">hand shook like mad</a>, but she pointed out that her brain wasn't shaking," Reno's sister, Maggy Hurchalla, said at the opening of the University of Florida Center for Movement Disorders and Neurorestoration last year, according to a statement.

    Reno told the American Academy of Neurology's <em>Neurology Now</em> in 2006 that even though the <a href="http://patients.aan.com/resources/neurologynow/index.cfm?event=home.showArticle&id=ovid.com%3A%2Fbib%2Fovftdb%2F01222928-200602010-00006" target="_hplink">tremors associated with her condition</a> have become worse throughout the years, they have been mainly in her left hand.




  • Mao Zedong


    While the Chinese Communist leader's cause of death in 1976 is not 100 percent confirmed, Mao was believed to have <a href="http://www.nytimes.com/learning/general/onthisday/big/0909.html" target="_hplink">suffered from Parkinson's disease</a>, the <em>New York Times</em> reported.




  • Deborah Kerr


    Kerr, who had roles in "The King & I," "From Here to Eternity" and "An Affair to Remember," <a href="http://www.people.com/people/article/0,,20152961,00.html" target="_hplink">passed away from Parkinson's</a> at age 86 in 2007, <em>People</em> magazine reported.

    TCM reported that the actress was <a href="http://www.tcm.com/tcmdb/person/101216%7C37331/Deborah-Kerr/" target="_hplink">diagnosed with the condition in 1994</a>, and had to use a wheelchair.




  • Johnny Cash


    The iconic country music singer and Rock and Roll Hall of Fame inductee <a href="http://www.cnn.com/SHOWBIZ/9710/27/johnny.cash/" target="_hplink">publicly announced his diagnosis</a> in 1997, CNN reported. At the time, his condition spurred cancellations of book promotions and concert tours.

    Cash ultimately <a href="http://www.usatoday.com/life/music/news/2003-09-12-cash-obit_x.htm" target="_hplink">died from diabetes complications</a> in 2003 at age 71, <em>USA Today</em> reported.




  • Billy Graham


    Reverend Billy Graham publicly announced that <a href="http://www.cbc.ca/news/background/graham_billy/" target="_hplink">he had Parkinson's</a> in 1992 at age 73, CBC News reported.

    His spokesman said at the time that "Evangelist Billy Graham has known for about three years that he is in the <a href="http://articles.philly.com/1992-07-03/news/26027174_1_graham-spokesman-larry-ross-crusade-parkinson" target="_hplink">early stages of Parkinson's disease</a>," the <em>Philadelphia Daily News</em> reported. "It was diagnosed during a routine checkup at the Mayo Clinic. His early manifestations were a mild tremor that causes difficulty in handwriting and some difficulty in gait and in descending steps without a rail. Both symptoms improved significantly with a modest amount of medication."

    Today, Graham also <a href="http://www.charlotteobserver.com/2011/05/11/2289457/evangelist-billy-graham-hospitalized.html" target="_hplink">suffers from macular degeneration</a> and hearing loss, and was most recently hospitalized because of pneumonia, the <em>Charlotte Observer</em> reported.




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