““Lithium regulates the proteins that control the body’s inner clock. This clock runs, oddly, on DNA, inside special neurons deep in the brain. Special proteins attach to people’s DNA each morning, and after a fixed time they degrade and fall off. Sunlight resets the proteins over and over, so they hold on much longer. In fact, the proteins fall off only after darkness falls—at which point the brain should “notice” the bare DNA and stop producing stimulants. This process goes awry in manic-depressives because the proteins, despite the lack of sunlight, remain bound fast to their DNA. Their brains don’t realize they should stop revving.””
