Is There A Link Between Bi-Polar Disorder and Parkinson’s Disease?

According to a new study out of China, bipolar patients are seven times more likely to develop Parkinson’s disease.  This remarkable discovery could provide a key to understanding the roots of both conditions and, perhaps, how to develop new treatments for them. 

The study was led by Taipei Veterans General Hospital psychiatric doctor, Huang Mao-Hsuan. Using data from two groups of adults, collected from the Taiwan National Health Insurance Research Database between 2001 and 2009, the team compared data between 56,000 bipolar patients with 225,000 who had never been diagnosed.  

Next, they reexamined the entire study population in 2011 to see how many had received a subsequent diagnosis of Parkinson’s. They found that those with bipolar disorder were far more likely to be diagnosed—at a rate of 0.7 percent to 0.1 percent.

Study author Mu-Hong Chen, MD, PhD of Taipei Veterans General Hospital explains, “Previous studies have shown a relationship between depression and Parkinson’s disease, but few studies have looked at whether there is a relationship between bipolar disorder and Parkinson’s.” 

Parkinson’s disease, of course, is complex in nature. It is categorized by the gradual decline in dopamine levels produced by brain cells.  Eventually, this results in physical impairment and other bodily function. We do not know what causes it and, thus, are not able to cure it; yet. 

Similarly, bipolar disorder—also known as manic-depressive illness—is categorized by fluctuating in mood that are often extreme, as well as shifts in concentration and energy levels.  While we have identified some genetic relationships with the disorder, there is still no known cause, nor is there a cure. 

While the data certainly suggests that there is some kind of correlation, there is still no understanding as to how the mechanism works. Obviously, then, this does not really serve to move us closer to a direct treatment, but it opens the door to new investigation and analysis. 

Chen goes on to say, indeed, that further studies are necessary in order to determine whether or not these two diseases share underlying processors or specific changes in the brain. Chen notes, “These could include genetic alterations, inflammatory processes or problems with the transmission of messages between brain cells. If we could identify the underlying cause of this relationship, that could potentially help us develop treatments that could benefit both conditions.”

The results of this study have been published in the journal Neurology.