1. From the Mood and Anxiety Disorders Program, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Md (Dr. Low); the Centre for Clinical Epidemiology and Community Studies, Sir Mortimer B. Davis Jewish General Hospital (Dr. Galbaud du Fort) and the Department of Psychiatry, McGill University (Drs. Galbaud du Fort and Cervantes), Montreal, Quebec, Canada.