1. Program in Placebo Studies, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
2. Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
3. Department of Clinical Psychology and Psychotherapy, Philipps University Marburg, Marburg, Germany
4. Department of Psychology, Endicott College, Beverly, Massachusetts
5. Weill Cornell Medical College, New York, New York