This study was supported by Contract 290-97-0011 from the Agency for Healthcare Research and Quality(AHRQ) (Task No. 3 to support the U.S. Preventive Services Task Force). We acknowledge the ongoing guidance and assistance of David Atkins, MD, MPH, Director of the Preventive Services Program at AHRQ; Dana Best, MD, MPH, AHRQ Task Order Officer; and the continuing support of Jacqueline Besteman, JD, MA, the EPC Program Officer. The investigators deeply appreciate the considerable support and contributions of faculty and staff from the University of North Carolina at Chapel Hill - Timothy S. Carey, MD, M.P.H., Gordon H. DeFriese, PhD, Anne Jackman, MSW, and Carol Krasnov.

They are equally grateful to Linda Lux, MPA, and Sonya Sutton, BSPH, from Research Triangle Institute for substantive project assistance and to Sheila White and Loraine Monroe for superior secretarial support.

We appreciate the efforts of the following external peer reviewers who provided insightful and constructive suggestions for improvements in the systematic evidence review: David Brody, MD, Hahnemann University Hospital, Philadelphia, PA; Elizabeth Costello, PhD, Duke University, Durham, NC; Allen Dietrich, MD, Dartmouth Medical School, Hanover, NH; Wayne Katon, MD, University of Washington, Seattle, WA; Kathryn Magruder, Medical University of South Carolina, Charleston, SC; Mary Mitchell, American College of Obstetricians and Gynecologists, Washington, DC; Herbert Schulberg, University of Pittsburgh, Pittsburgh, PA; H. R. Taylor, MD, MC, USN; Mary Whooley, MD, VA Medical Center, San Francisco, CA.