The use of lithium in psychiatry goes back to the mid-19th century. Early work, however, was soon forgotten, and John Cade is credited with reintroducing lithium to psychiatry for mania in 1949. Mogens Schou undertook a randomly controlled trial for mania in 1954, and in the course of that study became curious about lithium as a prophylactic for depressive illness. In 1970, the United States became the 50th country to admit lithium to the marketplace. Meanwhile, interest in lithium for the prophylaxis of depression was growing apace and today the agent is widely prescribed for that indication, even though it has not been accepted by the Food and Drug Administration. Lithium was almost derailed by a small group of opponents from the Maudsley Hospital and its status today is threatened by the "mood stabilizers."