In a new study, researchers found apathy offers an important early warning sign of dementia in individuals with cerebrovascular disease, but depression does not.
The research was conducted by a team at the University of Cambridge and elsewhere.
Depression is often thought to be a risk factor for dementia but this may be because some depression scales used by clinicians and researchers partially assess apathy.
The study is the first to examine the relationships between apathy, depression, and dementia in individuals with cerebral small vessel disease (SVD).
SVD may occur in one out of three elderly individuals, causes about a quarter of all strokes, and is the most common cause of vascular dementia.
Apathy, defined as a reduction in ‘goal-directed behavior’, is a common neuropsychiatric symptom in SVD, and is distinct from depression, which is another symptom in SVD.
Although there is some symptomatic overlap between the two, previous MRI research linked apathy, but not depression, with white matter network damage in SVD.
The team studied two independent cohorts of 450 SVD patients, one from the UK and the other from the Netherlands.
Across both cohorts, they found that individuals with higher baseline apathy, as well as those with increasing apathy over time, had a greater risk of dementia.
In contrast, neither baseline depression nor change in depression had any detectable influence on dementia risk.
These findings were consistent despite variation in the severity of participants’ symptoms, suggesting that they could be generalized across a broad spectrum of SVD cases.
The link between apathy and dementia remained after controlling for other well-established risk factors for dementia including age, education, and cognition.
The team says continued monitoring of apathy may be used to assess changes in dementia risk and inform diagnosis.
Individuals identified as having high apathy, or increasing apathy over time, could be sent for more detailed clinical examinations, or be recommended for treatment.
The study provides the basis for further research, including the mechanisms that link apathy, vascular cognitive impairment, and dementia.
One author of the study is Jonathan Tay, from Cambridge’s Department of Clinical Neurosciences.
The study is published in the Journal of Neurology, Neurosurgery & Psychiatry.
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