The difference between the origin of Alzheimer's disease (AD) and its symptoms is an obstacle to finding effective treatments. Scientists focused on amyloid-β (Aβ) plaques and tau aggregates to slow neurodegeneration and cognitive decline. Without identifying what causes AD, approved treatments do not provide much benefit. However, new findings suggest that restoring lithium levels in the brain could prevent and treat AD. Not just any lithium would work, just the forms that do not bind to Aβ.