Harvard Medical School researchers have uncovered a pivotal association between lithium deficiency in the brain and the progression of Alzheimer's disease. Their decade-long study, involving murine models and human tissue analysis, found that lithium binds to amyloid plaques, leading to depletion in critical brain regions and accelerating neurodegenerative pathology and memory decline. Treatment with amyloid-evading lithium orotate reversed pathological markers, prevented neuronal damage, and restored cognitive function in mice. These findings propose lithium measurement as an early diagnostic biomarker and highlight therapeutic potential for lithium compounds that avoid sequestration by amyloid beta deposits.