Although suicide accounts for about 11 per 100,000 deaths in the United States per year, little is known about how to prevent it. Factors that have been studied as possible modifiable risks include depression and other mood disorders, the availability of lethal means, and substance abuse. Of note, almost two thirds of persons who commit suicide have had contact with their primary care physician in the month before their death, and up to 83 percent were in contact with their physicians in the previous year, suggesting that improved screening of patients with suicide risk factors could reduce suicidal behavior. Mann and colleagues conducted a systematic review of previous studies evaluating the effectiveness of suicide prevention interventions in 15 countries (see accompanying table).

Outcomes included attempted or completed suicide, suicidal ideation, help-seeking behavior, identification of at-risk behavior, entry into treatment, and antidepressant prescription rates. Public education campaigns have had modest effects on attitudes but no detectable effects on suicide rates. Improving physician recognition of depression appears to be of benefit in some studies (including one targeting treatment of older patients and another providing support to physicians treating adolescents) but not in others. Interventions focusing on gatekeepers, such as clergy, caregivers of older patients, or other members of the community, have been successful in multilevel programs conducted in institutional settings.

Screening efforts can identify high-risk individuals, but according to a U.S. Preventive Services Task Force review, there are insufficient studies to determine whether there is any benefit to screening for suicide in a primary care setting. Although there are not enough prospective studies to determine whether antidepressant prescriptions reduce suicidal behavior, high prescription rates often correlate with lower suicide rates. Controversy about the ambiguous role of selective serotonin reuptake inhibitors in promoting or decreasing suicide in children and adolescents has led to increased scrutiny in prescribing of antidepressants to young patients. Numerous studies have shown benefits of psychotherapy in reducing suicide, repetition of suicidal behavior, and intermediate outcomes such as depression. Restricting lethal means reduces suicides, but substitute methods may obscure the benefits in some settings. Media presentations of suicide often produce imitators. Some evidence, such as concurence of decreased media reporting with decreased suicide rates, suggests a benefit for altered media reporting practices.

The authors conclude that the most promising interventions for suicide prevention are physician education, means restriction, and gatekeeper education.