1. The Baron Edmond de Rothschild Chemical Dependency Institute, Beth Israel Medical Center, 160 Water Street, FL 24, New York, NY 10038, USA
2. Department of Psychiatry and Behavioral Medicine, Center for AIDS Intervention Research, Medical College of Wisconsin, Milwaukee, WI 53226, USA
3. NYU College of Nursing, New York, NY 10003, USA
4. Rollins School of Public Health, Emory University, Atlanta, GA 30329, USA
5. Department of Hygiene, Epidemiology and Medical Statistics, Athens University Medical School, 11527 Athens, Greece
6. Department of Public Health, University of Tartu, 50411 Tartu, Estonia