Depressed People Three Times More Likely to Develop Parkinson's Disease

Scientists from Taiwan state that depression can triple the risk of developing Parkinson's disease - a common neurodegenerative disorder.

The study, published online in the medical journal Neurology, found that people with depression were three times more likely to develop Parkinson's than those who were not depressed. Depression generally occurs in people who are already diagnosed with Parkinson's disease, but this is the first study to confirm that mental illness can precede Parkinson's symptoms.

"Depression is linked in other studies to illnesses such as cancer and stroke," study author Albert C. Yang, MD, PhD, with Taipei Veterans General Hospital in Taipei, Taiwan, said in a statement. "Our study suggests that depression may also be an independent risk factor for Parkinson's disease."

They concluded this after analyzing the medical reports of 4,634 depressed patients and 18,544 people who were never diagnosed with depression. Both the groups were followed for 10 years. Researchers noticed that during the study period 1.42 percent depressed people were diagnosed with Parkinson's disease compared to the 0.52 percent of the non-depressed people. They concluded that people with depression were 3.24 times more likely to develop Parkinson's disease.

It is still unclear whether the onset of depression is an early warning for Parkinson's disease or if it is an independent risk factor for the disease.

Scientists from Taiwan are not the first to discover this link.  In the year 2002, Maastricht University, Netherlands, revealed that people with depression are three times more likely to develop Parkinson's disease than people who are not depressed.

The present finding was supported by Taipei Veterans General Hospital and Taiwan National Science Council.