Although the health plans of many nations and the World Health Organization call for programs to reduce suicide rates, relatively little is known about key risk factors that could be targeted in suicide prevention programs. Mortensen and colleagues used Danish population registers to study the relative contribution of various risk factors for suicide.

They made use of data registries containing information on the Danish population who were 16 to 78 years of age between 1980 and 1994. The information included data on employment and psychiatric illnesses. During the study period, 811 suicides occurred. These persons were matched with 79,871 control subjects, and multiple statistical analyses were performed to identify key variables associated with suicide.

Suicide rates were higher in residents of urban areas compared with nonurban residents. The risk of suicide was also increased with unemployment, single status, low income and receipt of pension or social security benefit. The strongest risk factor concerned admission to a psychiatric hospital. Almost one half of the persons who committed suicide had a history of admission to psychiatric facilities. Regardless of diagnosis, the greatest risk was during hospital admission and in the first week following discharge. Among psychiatric patients, the risk was increased only in those diagnosed as manic-depressive. Patients with alcohol and/or substance abuse were not at increased risk compared with other psychiatric patients. Overall, the attributable risk for admission to a psychiatric hospital was 44.6 percent. The other leading attributable risks were 3 percent for unemployment and 10.3 percent for single status.

The authors conclude that suicide prevention programs should pay special attention to psychiatric inpatients and patients recently discharged from psychiatric hospitals. They believe that the other factors, such as unemployment and single status, could be related to undiagnosed or preclinical psychiatric illness. While no single intervention can be expected to prevent all suicides, programs to improve the detection, treatment and follow-up of psychiatric illness, especially by family physicians, offer the greatest potential of reducing suicide rates.

editor's note: European studies, especially in Scandinavian countries, have contributed greatly to our understanding of the epidemiology of psychiatric disorders because they have an unparalleled ability to study complete populations. Projecting these results to the United States population is complicated by the heterogeneity of the American population. European studies also tend to emphasize the effects of unemployment, social cohesion and socioeconomic factors that, if considered, may be measured differently in American studies. In the case of suicide, the availability of guns is a major factor. A small proportion of European suicides involve guns, whereas in the United States, access to handguns contributes substantially to successful suicides, especially in males. None of these factors, however, detracts from the major message of this study—that the most powerful preventive intervention for suicide is vigilant and expert primary care.—a.d.w.