Why Apathy May Be A Better Indicator Of Dementia Risk Than Depression

Dementia, in its various forms, affects an estimated 5 million (and growing) people over 651 in the United States. While research into the causes and potential treatments are ongoing and prolific, there's still no cure or real treatment available.

According to a study published this week in the Journal of Neurology, Neurosurgery & Psychiatry, the previous belief that depression can be a predictor of dementia may not be entirely correct. The researchers propose that apathy—which is often assessed as a part of depression tests but is not the same thing—may be a better predictor.

"There has been a lot of conflicting research on the association between late-life depression and dementia," explains Jonathan Tay, Ph.D., from Cambridge's Department of Clinical Neurosciences. "Our study suggests that may partially be due to common clinical depression scales not distinguishing between depression and apathy."

The study, which involved researchers from the universities of Cambridge, King's College London, Radboud, and Oxford, included subjects from the U.K. and the Netherlands. Participants were assessed for apathy, depression, and dementia regularly over the course of several years.

So what is apathy exactly? It's defined as a lack of "goal-directed behavior" and is commonly seen in patients with cerebral small vessel disease2 (SVD), a group of diseases that affect the small arteries, arterioles, venules, and capillaries of the brain. It is the most common cause of vascular dementia but is also a common cause of strokes.

In this study, the researchers saw that patients who showed higher apathy or increased apathy over time had a greater risk of developing dementia, while high levels of depression or increased depression over time did not have any clear link to dementia risk.

While there are some similarities between symptoms of depression and apathy, previous MRI research has linked apathy specifically to white matter system damage in patients with SVD, while depression has not shown the same physical link.

As there is still not a cure for dementia or SVD, early detection and management are the best treatment options. This new research shows that the practice of using depression broadly as an indicator neglects a more specific indicator of risk in apathy.

"Continued monitoring of apathy may be used to assess changes in dementia risk and inform diagnosis," he explains. "Individuals identified as having high apathy, or increasing apathy over time, could be sent for more detailed clinical examinations, or be recommended for treatment."

This research offers a starting point for further research into why apathy may be linked to future onset of dementia and how this knowledge can be used to inform treatment and testing plans.

"Understanding these relationships better could have major implications for the diagnosis and treatment of patients in the future," says Tay.