Presented as a poster at the annual meeting of the American Academy of Child and Adolescent Psychiatry, Anaheim, Calif., Oct. 27–Nov. 1, 1998. Received Jan. 15, 1999; revision received July 19, 1999; accepted Aug. 24, 1999From the Divisions of Clinical and Genetic Epidemiology and Child Psychiatry, New York State Psychiatric Institute, Columbia University College of Physicians and Surgeons. Address reprint requests to Dr. Ferro, Division of Clinical and Genetic Epidemiology, New York State Psychiatric Institute, Columbia University, 1051 Riverside Dr., Unit 24, New York, NY 10032; firstname.lastname@example.org (e-mail). Supported by NIMH grants MH-16434 and MH-43878 and by the Samuel Priest Rose Research Award. The authors thank Talia Zaider, B.A., Mark Davies, M.P.H., Bob Falanga, M.A., Dory Dickman, M.A., Yuju Ma, M.S., Laura Mufson, Ph.D., Donna Moreau, M.D., Rachel Klein, Ph.D., Lisa Kentgen, Ph.D., Robert Spitzer, M.D., Janet Williams, D.S.W., and Jeffrey Johnson, Ph.D., for their help in different phases of this study.