by Emily Stembridge
Older adults with depression face a unique obstacle — dealing with both a mental illness and the challenges that come along with aging. Currently, there are no treatments on the market targeting depression in this specific group.
The Department of Psychiatry and Behavioral Sciences has received a grant to study Sinemet, which may change that. Sinemet, a brand name for the drug levodopa, has historically treated Parkinson’s disease, a brain disorder characterized by injury to dopamine-producing neurons.
While people with depression do not have the same type of damage to these neurons, their dopamine system still may not be working as efficiently as it could. Levodopa helps patients produce more dopamine, leading researchers to believe it may also be effective in treating some elderly patients with depression.
“We know that dopamine is an important neurotransmitter, and that as we get older our dopamine system changes,” said Warren Taylor, MD, MHSc, James G. Blakemore Professor of Psychiatry and director of the Division of Geriatric Psychiatry.
“Dopamine has been a focus for treating many other psychiatric conditions, but not so much for depression,” he said. “We want to understand how changes in the dopamine system contribute to this unique form of depression and whether individuals with specific depressive symptoms may be more likely to respond to it. This would help us better target treatments to the individual.”
Depression in older adults is unique for several reasons — one being an accumulation of life experiences, and another being the natural process of aging.
“In our elderly patients, we see life experiences such as divorce, serving as a caregiver for a loved one or the loss of family and friends contribute to the likelihood of depression,” Taylor said. “We also see more medical issues such as chronic pain, cardiovascular disease or Alzheimer’s, which may also predispose them to depression.”
Dopamine commonly affects cognitive processes such as memory function, motivation and the ability to enjoy everyday tasks, but it also plays a significant role in physical processes such as speed, balance and agility. This may give it the ability to better treat older adults with depression who experience both mental and physical symptoms.
“We hypothesize that enhancing activity in the dopamine system will help ease depression symptoms,” Taylor said. “We hope that Sinemet will help older adults feel more motivated and interested in their daily lives.
“Both their mental and physical speed may improve. Will this help people feel better? And if so, what can this tell us about how the brain and the dopamine system work in depression?”
The study, a collaborative project with Columbia University, will be assessed using both clinical and neuroimaging tests. Participants will take part in MRI scans, which will show researchers if older brains work differently with the ability to produce additional dopamine. If the answer is yes, researchers may be able to apply their findings about the dopamine system to a wider range of patients with depression.
“My hope is that this will help personalize treatment for individuals,” Taylor said. “If someone is depressed and slowed down, we want to know if this type of treatment can target the problems they’re having. If this is successful, we’ll know if the dopamine system is something we should pay more attention to in developing future drugs and treatments for depression.”
