Narrowing of the small blood vessels in the brain, also known as cerebral small vessel disease (SVD), is one of the leading causes of dementia, due to the damage this causes in areas of the brain associated with cognition. Apathy, defined as a reduction in goal-directed behavior, is a common neuropsychiatric symptom of SVD, but is sometimes confused with depression, partly because the clinical scales used to measure apathy and depression overlap in content.
In their research study, published in the Journal of Neurology, Neurosurgery & Psychiatry on 11 July, Dr. Jonathan Tay and colleagues aimed to determine whether apathy or depression were predictors of dementia in people with SVD. Using two prospective cohort studies of SVD (the St. Georges Cognition and Neuroimaging in Stroke study/SCANS and the Radboud University Nijmegen Diffusion Tensor and Magnetic Resonance Cohort study/RUN DMC) they analysed baseline brain imaging and cognitive test scores for over 450 participants. Depression and apathy was assessed using specific neuropsychiatric questionnaires. The researchers also analysed longitudinal data from 104 SCANS study participants to evaluate whether depression or apathy could predict the development of dementia over time.
While there were some differences in the incidence of dementia between the two cohorts (19.8% and 10.8% of SCANS and RUN DMC participants, respectively), Dr. Tay and colleagues found that individuals with higher apathy scores at baseline across both cohorts had a greater risk of developing dementia. Longitudinal data from SCANS showed that increasing apathy was associated with a 53% increased likelihood of dementia. In contrast, depression did not predict dementia in either cohort, suggesting that apathy, but not depression, may be a prodromal symptom of dementia in people with SVD.
https://jnnp.bmj.com/content/early/2020/07/10/jnnp-2020-323092
