Presented in part at the 40th Annual Meeting of the American College of Neuropsychopharmacology, Waikoloa, Hawaii, Dec. 9–13, 2001, and the 155th Annual Meeting of the American Psychiatric Association, Philadelphia, May 18–23, 2002. Received April 9, 2003; revision received July 15, 2003; accepted July 17, 2003. From the Department of Psychiatry, Weill Medical College of Cornell University, New York; and the Bipolar Disorders Research Clinic, Payne Whitney Clinic, New York Presbyterian Hospital, New York. Address correspondence to Joseph F. Goldberg, M.D., The Zucker Hillside Hospital, 75-59 263rd St., Glen Oaks, NY 11004; firstname.lastname@example.org (e-mail). Supported by NIMH K23 Career Development Award MH-01936, research grants from the Theodore and Vada Stanley Foundation and the Nancy Pritzker Foundation, a National Alliance for Research on Schizophrenia and Depression Young Investigator Award, and resources from a fund established in the New York Community Trust by DeWitt Wallace (Dr. Goldberg). Study drug and funds to compound matching placebo were provided by Pharmacia. The authors thank Joseph R. Calabrese, M.D., for helpful comments.