Presented at the 151st annual meeting of the American Psychiatric Association, Toronto, May 30–June 4, 1998, and Washington, D.C., May 15–20, 1999; and at meetings of the World Psychiatric Association in Madrid, Aug. 23–28, 1996; Rome, June 16–19, 1997; and Hamburg, Aug. 6–11, 1999. Received Feb. 11, 2000; revisions received Aug. 10 and Nov. 14, 2000; accepted Dec. 1, 2000. From the Department of Psychiatry, Columbia University College of Physicians and Surgeons. Address reprint requests to Dr. Spinelli, New York State Psychiatric Institute, 1051 Riverside Dr., Box 123, New York, NY 10032; firstname.lastname@example.org (e-mail). Supported in part by NIMH grant MH-01276. The author thanks Prof. Channi Kumar, Debra Sichel, M.D., Katherine Wisner, M.D., and Jean Endicott, Ph.D., for their assistance on this project.