1. The authors are with the Neuropsychopharmacology Research Unit, Department of Psychiatry, New York University Medical Center, 550 First Ave., New York, N.Y. 10016, where Dr. Friedman is Instructor in Experimental Psychiatry, Dr. Shopsin is Assistant Professor of Psychiatry, Dr. Sathananthan is Clinical Instructor in Psychiatry, and Dr. Gershon is Professor of Psychiatry.