Men of all age and race groups are more likely than women to commit suicide, and white men are at highest risk. Firearms are the most frequently used method of suicide for both men and women. From 1970 to 1984, the proportion of suicides committed with firearms increased 17 and 59 percent, respectively, for men and women. The second method of choice for men is by hanging; and the third, poisoning by gas. The second method of choice for women is drug overdose. Risk factors for suicide include psychiatric illnesses, personality disorders, alcoholism, family history of suicide, and low concentrations of certain neurotransmitter metabolites. Anecdotal evidence seems to indicate that, among teenagers and young adults, suicide may be influenced by exposure to suicide or suicidal behavior by others. Situational risk factors for suicide include stressful life events, loss or disruption of social support mechanisms, and absent or inadequate social networks. Interventions for suicide prevention can be divided into five major categories: (1) improving the identification, referral, and treatment of persons at high risk; (2) treating risk factors, such as clinical depression or alcoholism; (3) decreasing individual vulnerability to suicide through education; (4) making self-referral resources accessible to suicidal persons; and (5) limiting access to lethal means of suicide, such as firearms, prescription drugs, and high places. Sources of data on the incidence of suicide are noted. 55 references