Study shows for the first time that lithium plays an essential role in normal brain function and can confer resistance to brain aging and Alzheimer’s disease. The findings — 10 years in the making — unify decades-long observations in patients, providing a new theory of the disease and a new strategy for early diagnosis, prevention, and treatment. Conclusions are based on a series of experiments in mice and on analyses of human brain tissue and blood samples from individuals in various stages of cognitive health.

Cholesterol in the brain is essential for the maintenance and function of neurons, and this study shows that neuronal uptake may be impaired in Alzheimer’s disease, potentially contributing to their degeneration.

The findings suggest that the APOE4 genetic variant, known as a genetic risk factor for Alzheimer’s, reduces the efficiency with which neurons absorb the cholesterol they need to function, which could promote their dysfunction and degeneration.

The research, coordinated by Sant Pau and published in the Journal of Lipid Research, sheds new light on the role of lipid metabolism in Alzheimer’s disease and opens up new avenues for study and intervention.