Received Nov. 5, 2001; revised Feb. 25, 2003; accepted March 17, 2003. From the Department of Psychiatry, Weill Medical College, Cornell University; New York University Child Study Center, New York; and the Department of Molecular Virology, Immunology, and Medical Genetics, College of Medicine, and the Department of Oral Biology, College of Dentistry, Ohio State University, Columbus, Ohio. Address reprint requests to Dr. Altemus, Department of Psychiatry, Weill Medical College, 1300 York Ave., Box 244, New York, NY 10021; firstname.lastname@example.org (e-mail). Funded in part by a grant from the Dewitt Wallace Reader’s Digest Fund to Dr. Altemus, an NIMH grant (MH-57883) to Dr. Cloitre, and a research grant from the John D. and Catherine T. MacArthur Foundation to Dr. Dhabhar. The authors thank Jessica Zonana for help with manuscript preparation, Ruirong Yang for help with cortisol assays, Karen Heffernan, Lisa Cohen, and Karestan Koenan for help with clinical characterization of PTSD subjects; and Bruce McEwen for advice and support.