How Depression and Parkinson's Might Be Linked

Parkinson's disease was more common in depression patients

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Depression is a complex illness with many possible causes and many treatments. And it may increase the risk of another serious health condition.

A new study found that depression may be tied to a higher risk of developing Parkinson’s disease.

The authors of this study looked at patients with depression and compared them to those without depression to see whether the mental illness increased Parkinson’s disease risk.

They found that a depression diagnosis was tied to an almost threefold increased risk of Parkinson’s compared to patients who weren't depressed. Although the risk was increased for depression patients, the overall risk of Parkinson's remained relatively low.

“We saw this link between depression and Parkinson's disease during over a timespan of more than two decades, so depression may be a very early symptom of Parkinson's disease or a risk factor for the disease," said lead study author Peter Nordström, PhD, of Umeå University in Sweden, in a press statement.

Patients who are feeling depression symptoms — sadness, hopelessness, loss of interest in daily activities, sleep trouble and appetite changes, among others — should seek medical care. Many medications and therapies can fight depression and help patients live normal lives.

Parkinson’s disease is a condition of the central nervous system. It is usually accompanied by tremors, impaired mobility and muscle stiffness.

For this study, Dr. Nordström and team looked at more than 140,000 patients who were diagnosed with depression. They compared each of those patients with three other people of the same sex and age who did not have depression.

Dr. Nordström and team followed up with these patients for up to 26 years.

Over the course of this study, 1.1 percent of the depression patients were diagnosed with Parkinson’s. Only 0.4 percent of the patients who weren't depressed developed Parkinson’s.

Also, more severe depression appeared to increase the risk of Parkinson’s even more. People who had been hospitalized due to depression were 3.5 times more likely to be diagnosed with Parkinson’s than people who had not been hospitalized for their depression, Dr. Nordström and team found.

This study was published May 20 in the American Academy of Neurology's journal Neurology.

The Swedish Research Council funded this research. The authors disclosed no conflicts of interest.

Review Date: 
May 18, 2015
Last Updated:
May 28, 2015