Lithium salts are commonly used for psychiatric disorders, and the results of three clinical trials of the use of lithium salts for the treatment of AD have been published, but lithium salts failed to demonstrate neuroprotective activity or improvements in cognitive or psychometric scores and did not affect CSF Aβ42, pTau181, pTau231, or total tau levels [174]. This evidence concerns the gene MAPT and Alzheimer disease.