Quantum Mechanics Meets Your Lithium Prescription

Rats fed one version of lithium settled down more than rats fed the other. The two versions are a single neutron apart. A computer model proposes vitamin C as the go-between.

Lithium has treated bipolar disorder since 1948, and its exact workings are still unresolved. It comes in two stable forms, lithium-6 and lithium-7. Their masses differ by roughly 14 percent, and the added neutron also changes the nuclear spin, a quantum property that lets a nucleus interact magnetically with nearby electrons.

In an earlier experiment, male rats ate lithium for 30 days, then got ketamine to make them hyperactive. Every lithium group moved less than the controls. Lithium-6 damped the activity harder and longer than lithium-7.

A September 2026 paper in PLOS One offers a possible reason. It is a computer modeling study that tested zero people and zero animals; the rat data come from that earlier work.

The simulation pairs flavin, a molecule that works inside proteins, with a vitamin C byproduct called the ascorbyl radical, which the authors describe as plentiful in brain tissue and long-lasting. Each carries one unpaired electron. How the two spins line up decides whether the pair snaps back into stable molecules or drifts apart. A lithium ion can cling to that radical, close enough for its nucleus to nudge the outcome.

In the model, the isotope mattered. At a magnetic field matching Earth's, the simulated chemistry split between isotopes by a ratio of 1.16. The rats' activity split by 1.3, a comparison the authors call coarse.

The authors label the mechanism hypothetical. The predicted reaction yields are small, and the route from this chemistry to a rat's behavior is nowhere near settled.

Two lithiums, one neutron apart. Somehow the rats could tell.

Read the full story at PLOS One, September 10, 2026

Hot Take: Quantum physics went looking for how lithium works and came back with orange juice. Love that for science, but so far only a computer is convinced.