Tau pathology and depression interact to accelerate driving decline in cognitively normal older adults

Driving is a complex task that can be compromised by mood disorders and neurodegenerative conditions. Major depressive disorder (MDD) and Alzheimer's disease (AD) increase in prevalence with older age. Preclinical AD, identified through protein biomarkers, is strongly associated with an increased risk of developing AD. This study tracked the daily driving behaviors of older adults over an average period of 54 months and found participants with MDD and Positron Emission Tomography (PET) biomarker tau had a faster increase in risky driving behaviors, such as hard braking, and a slower decline in randomness of driving patterns, compared to healthy controls. Notably, participants with MDD were more likely to exhibit PET tau positivity than PET amyloid positivity, suggesting a potential interaction between MDD and tau pathology. These findings highlight the importance of monitoring older drivers for emerging functional vulnerability associated with mood disorders and neurodegeneration at an early stage.