Results of a new study provide more evidence that depressive symptoms are an early feature of Parkinson's disease, preceding the characteristic movement problems seen Parkinson's such as tremor and rigid muscles.
In the study, researchers found that starting antidepressant therapy was associated with a twofold increased risk of developing Parkinson's disease in the next 2 years.
Although several reports have shown a link between depressive symptoms and Parkinson's disease, it was unclear whether one caused the other or if both may arise from some common mechanism, Dr. A. Alonso and colleagues note in their report.
To look into these questions, they matched 999 patients with Parkinson's disease identified through records from 1995 to 2001 to 6261 "control" subjects. Initiation of antidepressant therapy was used as a marker for depressive symptoms.
Overall, subjects who began antidepressant therapy were 85 percent more likely to develop Parkinson's disease than were non-initiators, Alonso, from the University of Minnesota, Minneapolis, and colleagues note.
Further analysis showed that the association was strongest in the 2 years after starting antidepressant therapy, they report in the latest issue of the Journal of Neurology, Neurosurgery, and Psychiatry.
Based on their findings, Alonso and colleagues suggest that people with signs of depression who start to develop movement problems "be promptly evaluated to rule out a diagnosis of Parkinson's disease."
