Presented in part at the seventh scientific meeting of the International Society for Magnetic Resonance in Medicine, Philadelphia, May 22–28, 1999, and the 38th annual meeting of the American College of Neuropsychopharmacology, Acapulco, Mexico, Dec. 12–16, 1999. Received April 4, 2002; revision received July 30, 2002; accepted Aug. 14, 2002. From the Departments of Psychiatry, Biomedical Engineering, Radiology, and Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Conn. Address reprint requests to Dr. Sanacora, Clinical Neuroscience Research Unit, Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, 34 Park St., New Haven, CT 06519; firstname.lastname@example.org (e-mail). Supported by grants from The Donaghue Medical Research Foundation (J.K., G.S.) and the Dana Foundation (G.S.), NIMH grant MH-01715 (G.S.), the Mental Health Clinical Research Center at Yale grant MH-30929 (J.K., G.S.), National Institute on Alcohol Abuse and Alcoholism grant AA-00261 (J.K.), and grants from the VA Research Enhancement Award Program and Yale Alcohol Center. The authors thank Lisa Roach, Michael Appel, Donna Fasula, and Matthew Wachen for their assistance.