MAPT and major depressive disorder: In terms of factors associated with WM functions of MCI patients, sex, age, psychiatric disorders such as depression, apolipoprotein 4 (ApoE4), and functional activity scores were not significantly correlated to CANTAB WM scores, while a higher cerebrospinal fluid (CSF) levels of tau-protein and amyloid-beta (Aβ) were associated with a lower function in WM tests.