Exploring the relationship between an age-related brain change and depression

A protein called tau has been linked to higher levels of depressive symptoms as people age and develop Alzheimer's disease. Researchers at Brandeis University studied data from the Alzheimer's Disease Neuroimaging Initiative to examine the connection between tau levels and depressive symptoms in older adults with and without cognitive issues.

The study found that in cognitively intact individuals, higher tau levels were associated with faster increases in depressive symptoms over time. Moreover, higher tau levels in these individuals predicted higher depression scores on standardized tests. These findings suggest that tau accumulation may precede and contribute to depressive symptoms.

Interestingly, these associations were not observed in individuals with Alzheimer's disease or mild cognitive impairment. The researchers conclude that early increases in tau levels during aging may be a contributing factor to rising depressive symptoms. They propose that tracking depressive trajectories in aging populations could serve as an additional tool to assess the risk of neurodegenerative diseases.

The researchers emphasize the importance of continued monitoring of tau levels and depression symptoms over longer periods, particularly as some individuals develop cognitive impairment or more severe depression. By tracking these trajectories and exploring their relationships with other measures of Alzheimer's disease development, researchers can gain a better understanding of which individuals may be at increased risk.