In the past 20 years the successful treatment of more than 1,000 cases of acute mania with lithium salts has been reported in the world literature. In addition, lithium compound has been reported to be effective when used prophylactically against recurrent mania<i>and</i>depression; more recently some uncontrolled clinical trials have reported efficacy in acute depression. Nevertheless, considerable controversy and skepticism continues to surround this drug, probably because of the low ratio of controlled to uncontrolled studies. Some clarification of the controversy should be provided by the results of a recent controlled study by Goodwin and associates reported in the<i>Archives of General Psychiatry</i>.<sup>1</sup>A group of 30 manic-depressive patients (12 manic and 18 depressed) were evaluated longitudinally at the National Institute of Mental Health. Double-blind ratings of mania and depression were recorded on a daily basis by a psychiatrist and a trained nursing research team. The design involved