Mood and Cognition Adversely Affected by Dopamine in Depressed People with PD
A new research study from the University of Kentucky College of Medicine and the Sanders Brown Center on Aging has shown some information about depression and PARKINSON’S DISEASE that was not typically expected. Lee Blonder, Ph.D. used a small group of 28 subjects, all with PARKINSON’S DISEASE, 10 of whom were depressed and 18 who were not to examine the effects of dopamine replacement on cognitive function and depression. HIs expectations were that cognitive function would improve for both depressed and non-depressed subjects with the addition of dopamine. To his surprise, this did not prove to be true.
All of the subjects underwent a baseline series of cognitive testing and tests to measure the severity of their depression. Then they were all retested both with and without their regular dopamine replacement therapies. Subjects who were depressed were found to have poorer performance on three measures of the cognitive testing when taking dopamine replacement than without the dopamine. Mood of the depressed subjects was also worse on dopamine. For subjects that did not have depression, performance on cognitive testing improved on dopamine therapy and their mood was stable.
The results of this study raise concerns about treatment options that may compromise the mental health and cognitive functioning of depressed patients with PARKINSON’S DISEASE. Dr. Blonder cautions that this is a very small preliminary study and should not be used to change treatment plans until additional larger studies confirm his findings. Depression is very common in PARKINSON’S patients, with perhaps 40% of patients affected.
Review by Marcia McCall