Researchers who wondered about the effectiveness of lithium drugs in treating patients with severe depression analyzed 22 studies involving 5,647 patients. The scientists, working at Harvard-affiliated McLean Hospital in Belmont, found through their analysis that those who took the drug showed a nine-fold lower rate of suicide compared to those who did not. “The evidence we have provides strong, consistent support that suicides are dramatically lower with than without long-term lithium treatment,” says Ross Baldessarini, a Harvard professor of psychiatry who participated in the study. He estimates that 10 million people in the United States with major mood disorders could be affected by these results. Baldessarini and colleagues Leonardo Tondo and John Hennen reported their results in recent issues of the international medical journal Acta Pyschiatrica Scandinavica and in the Annals of the New York Academy of Sciences.