From the National Institute of Mental Health Collaborative Program on the Psychobiology of Depression, Clinical Studies, conducted with the participation of the following investigators: M. B. Keller, MD (Chairperson, Providence, RI); W. Coryell, MD (Co-Chairperson, Iowa City, Iowa); H. S. Akiskal, MD, L. L. Judd, MD, J. D. Maser, PhD (San Diego, Calif); P.W. Lavori, PhD, T. I. Mueller, MD, M. T. Shea, PhD (Providence); J. Fawcett, MD, W.A. Scheftner, MD (Chicago, Ill); W. Coryell, MD, J. Haley (Iowa City); J. Endicott, PhD, A. C. Leon, PhD, J. Loth, MSW (New York, NY); J. Rice, PhD, T. Reich, MD (St Louis, Mo). Other contributors include: N. C. Andreasen, MD, PhD, P. J. Clayton, MD, J. Croughan, MD, G. L. Klerman, MD†, R. M. A., Hirschfeld, MD, M. M. Katz, PhD, E. Robins, MD, R.W. Shapiro, MD, R. L. Spitzer, MD, G. Winokur, MD†, and M. A. Young, PhD.