As well as helping to prevent the disease, researchers say their findings could support healthy brain aging in general.

A few limited clinical trials of lithium for Alzheimer’s disease have shown some efficacy, but the lithium compounds they used — such as the clinical standard, lithium carbonate — can be toxic to aging people at the high doses normally used in the clinic.

Lithium levels in human and mouse brains influence Alzheimer’s disease effects, but targeted replacement therapy may hold the key to intervention.