Depression May Be Early Sign of Parkinson's Disease

FRIDAY, April 27 (HealthDay News) -- In some cases, depression can be an early manifestation of Parkinson's disease, new research suggests.
Researchers at the Harvard School of Public Health compared antidepressant use among more than 1,000 individuals with Parkinson's disease to more than 6,600 age- and gender-matched individuals without the degenerative neurological illness.
They found that people currently on antidepressants had an 80 percent higher risk of developing Parkinson's disease than those who had never taken antidepressants. This was true for both men and women, regardless of age or the class of antidepressant used.
"We think this is not actually the medication that is causing Parkinson's disease. Instead, we think people who are going to get Parkinson's disease get depression first," said study co-author Dr. Alvaro Alonso, a research associate at Harvard. "It's very important not to say that people taking antidepressants have a higher risk of developing Parkinson's disease," he said.
That's because the effect was only apparent in the year prior to disease diagnosis, and because it was true for two different types of medications, tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs), which work via wholly different mechanisms, Alonso explained.
He noted that additional data, not included in the published study, indicated that newer users of antidepressants -- those who had been on the drugs for less than one year -- had a threefold higher risk of developing Parkinson's than people who had never used antidepressants.
Alonso's interpretation: Depressive symptoms could be one of the first manifestations of Parkinson's disease.
The research is scheduled to be presented May 1 at the annual meeting of the American Academy of Neurology, in Boston.
Dr. Rajesh Pahwa, director of the Parkinson Disease and Movement Disorder Center at the University of Kansas Medical Center, in Kansas City, called the observation "interesting."
At the same time, he said, the depression-Parkinson's link is "common knowledge" among neurologists, who have long recognized that depression often occurs alongside Parkinson's disease.