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Depression May Lessen Effectiveness of Parkinson’s Drugs

In an unexpected finding, new research suggests depression can hamper cognitive function among Parkinson’s’ patients receiving traditional dopamine replacement therapy.

Scientists from the University of Kentucky College of Medicine found that the dopamine replacement therapy commonly used to treat motor symptoms of Parkinson’s disease (PD) was associated with a decline in cognitive performance among depressed Parkinson patients.

In the study, as published in the journal Psychiatry Research, investigators found that in contrast, non-depressed Parkinson patients’ cognitive function improved on dopamine replacement therapy.

The study also found that mood in depressed Parkinson’s patients was actually worse while on dopaminergic medications.

“This was a surprise,” said Lee Blonder, Ph.D., the study’s principal investigator.

“It is the opposite of our original hypothesis that both groups of PD patients would improve in cognitive performance on dopaminergic medications, and that mood in the depressed PD group would also improve.”

A cohort of 28 patients with PD — 18 nondepressed and 10 depressed — were given a baseline series of tests to assess cognitive function and the incidence and severity of depression. They were then re-tested with and without their dopamine replacement therapy.

Results revealed a statistically significant interaction between depression and medication status on three measures of verbal memory and a facial affect naming task.

In all cases, depressed Parkinson’s patients performed significantly more poorly while on dopaminergic medication than while off. The opposite pattern emerged for the non-depressed Parkinson’s group.

Depression is a common and serious comorbidity in patients with Parkinson’s; studies suggest that approximately 40 percent of PD patients suffer from depression.

Blonder cautions that these results are to some extent preliminary due to the small cohort of 28 participants.

“Additional studies are required before these results should be used to alter treatment plans,” Blonder says.

But, “future research should ultimately focus on investigating treatment options for patients with Parkinson’s and depression to maximize patient function without compromising their mental health.”

Source: University of Kentucky

Depression May Lessen Effectiveness of Parkinson’s Drugs

Rick Nauert PhD

Rick Nauert, PhDDr. Rick Nauert has over 25 years experience in clinical, administrative and academic healthcare. He is currently an associate professor for Rocky Mountain University of Health Professionals doctoral program in health promotion and wellness. Dr. Nauert began his career as a clinical physical therapist and served as a regional manager for a publicly traded multidisciplinary rehabilitation agency for 12 years. He has masters degrees in health-fitness management and healthcare administration and a doctoral degree from The University of Texas at Austin focused on health care informatics, health administration, health education and health policy. His research efforts included the area of telehealth with a specialty in disease management.

APA Reference
Nauert PhD, R. (2015). Depression May Lessen Effectiveness of Parkinson’s Drugs. Psych Central. Retrieved on May 25, 2018, from https://psychcentral.com/news/2014/04/21/depression-may-lessen-effectiveness-of-parkinsons-drugs/68780.html

 

Scientifically Reviewed
Last updated: 6 Oct 2015
Last reviewed: By John M. Grohol, Psy.D. on 6 Oct 2015
Published on PsychCentral.com. All rights reserved.