The antidepressant effects of lithium carbonate were evaluated in a group of 52 hospitalized depressed patients, using a longitudinal double-blind design that involved alternating drug and placebo periods in the same patient. Thirty-six of the 52 patients showed some improvement on lithium, including 15 who had complete remission of symptoms. Virtually all of the antidepressant responses occurred in patients with a past history of mania or hypomania (the bipolar group).Abstract Teaser