Is There an Association Between Bipolar Disorder and Parkinson Disease?

According to a recent study, people with bipolar disorder were more likely to later develop Parkinson disease (PD) compared with patients who do not have the disorder.

Researchers evaluated a national Taiwanese health database searching for people who were diagnosed with bipolar disorder between 2001 and 2009 and who had no history of PD. These search criteria returned a result of 56,340 people, who were then matched with 225,350 individuals of the same age, sex, and who had never been diagnosed with bipolar disorder or PD as a control group. The groups were then followed until the end of 2011.

“Previous studies have shown a relationship between depression and Parkinson’s disease, but few studies have looked at whether there is a relationship between biopolar disorder and Parkinson’s,” said study authors Mu-Hong Chen, MD, PhD, Taipei Veterans General Hospital, in a press release.

Over the course of the study, 372 (.7%) people with bipolar disorder developed PD, compared with 222 (0.1%) people who did not have bipolar disorder who developed PD.

After adjusting for other factors that could affect the risk of developing PD, such as age, sex, the use of antipsychotic medications among other things, the study authors identified that patients with bipolar disorder were more likely to develop PD (hazard ratio [HR] 6.78; 95% CI, 5.74-8.02) than the control group. Furthermore, the researchers determined that a high frequency of psychiatric admission for manic/mixed and depressive episodes was also associated with an increased risk of developing PD.

The patients with bipolar disorder who developed PD notably did so at a younger age (64) than the control group (74). Additionally, people who were hospitalized more often for bipolar disorder were more likely to develop PD than those who were hospitalized less than once per year. In fact, those who were hospitalized more than 2 times per year were 6 times more likely to develop PD than those hospitalized less than once per year.

In order to fully investigate whether these diseases have an association with one another, further studies are needed. “If we could identify the underlying cause of this relationship, that could potentially help us develop treatments that could benefit both conditions,” Chen said in the statement.

Reference

Huan MH, Cheng CM, Huang KL, et al. Bipolar disorder and risk of Parkinson disease: a nationwide longitudinal study [published online May 22, 2019]. Neurology. doi.org/10.1212/WNL.0000000000007649