Every year approximately 30,000 people in the United States and one million worldwide die as a result of suicide.Over the last 100 years,suicides have out-numbered homicides by at least 3:2.Concerned with high suicide rates,several federal agencies joined together and asked the Institute of Medicine to convene the Committee on Pathophysiology and Prevention of Adolescent and Adult Suicide to examine the state of the science base,gaps in our knowledge,strategies for prevention,and research designs for the study of suicide.