Dimensional Approaches in Diagnostic Classification Refining the Research Agenda for DSM-V

John E. Helzer, M.D., is Professor of Psychiatry and Director of the Health Behavior Research Center at University of Vermont College of Medicine in Burlington, Vermont.Helena Chmura Kraemer, Ph.D., is Professor Emerita of Biostatistics in Psychiatry in the Department of Psychiatry and Behavioral Sciences at Stanford University in Palo Alto, California.Robert F. Krueger, Ph.D., is Professor of Clinical Psychology, and Personality, Individual Differences, and Behavior Genetics in the Department of Psychology at the University of Minnesota in Minneapo--lis, Minnesota.Hans-Ulrich Wittchen, Ph.D., is Director of the Institute of Clinical Psychology and Psychotherapy at Technische Univer--sitat Dresden in Dresden, Germany.Paul J. Sirovatka, M.S., was Director of Research Policy Analysis at the Division of Research and American Psychiatric Institute for Research and Education at the American Psychiatric Association in Arlington, Virginia.Darrel A. Regier, M.D., M.P.H., is Executive Director of the American Psychiatric Institute for Research and Education and Director of the Division of Research at the American Psychiatric Association in Arlington, Virginia."