1. New York State Psychiatric Institute and Columbia University, New York, NY 10032
2. Department of Social Medicine, Hadassah University Hospital, Jerusalem, Israel
3. Division of Biostatistics, School of Public Health, Columbia University, New York, NY 10032;
4. Division of Epidemiology, School of Public Health, Columbia University, New York, NY 10032;
5. Brookdale Institute-JDC Israel, JDC Hill, Post Office Box 3489, Jerusalem 91034 Israel.