(HealthScoutNews) -- People with depression are three times more likely to develop Parkinson's disease than people who aren't depressed, according to 25-year study from the Netherlands.

Depression frequently affects people already diagnosed with Parkinson's, but this is the first study to show that depression can precede symptoms of Parkinson's, researchers from the University of Maastricht say in an article in tomorrow's issue of the journal Neurology.

Using a health registry, the scientists identified 1,358 people from a region in the southern Netherlands who were diagnosed with depression over a 15-year period. Those people were matched with 67,570 people born in the same year but never diagnosed with depression.

Both groups were followed for up to 25 years to determine how many of them developed Parkinson's. The researchers found that 19 of the 1,358 depressed people developed Parkinson's, a much higher percentage than the 259 of the 67,570 people with no depression.

Previous studies have shown that people with Parkinson's have lower levels of the neurotransmitter called serotonin. Low levels of serotonin play a key role in depression.

More information

The Parkinson's Disease Foundation has more information on the disease, and the New York University School of Medicine psychiatry site offers this depression screening test.

Reference Source 101

For more information on how to prevent other diseases, use
PreventDisease.com's "Quick Prevention Resources".