Tau and Depression: A Systematic Review

Objectives: The tau protein is essential for stabilizing microtubules. Changes in its phosphorylation are identified in many neurodegenerative diseases, such as frontotemporal dementia and Alzheimer's disease. The hyperphosphorylation of the tau protein is linked to various factors, including stress, which has a substantial impact on depressive illness. The present study aimed to systematically review studies that describe the association between tau protein and depression.Design: The present study used the PRISMA statement 2020 as the inclusion criterion for articles describing tau protein in individuals with depression. The exclusion criterion was the lack of comparison of tau protein levels with individuals without depression.Results: A total of 138 papers were identified, of which 21 were ultimately included. One out of every three articles included demonstrated the statistical significance of the tau protein values between the depression group and controls. Only one had an adequate sample but demonstrated results without any major significance.Conclusions: The association between tau protein and depression remains unclear. Studies with adequate sampling are necessary to answer this question.