Affective disorders and suicide risk: a reexamination

In 1970, Guze and Robins published a meta-analysis of suicide in patients with affective illness that inferred a lifetime risk of 15%. Since then, this figure has been generalized to all depressive disorders and cited uncritically in many papers and textbooks. The authors argue for an alternative estimate of suicide risk and question the generalizability of the Guze and Robins estimate.

The authors sorted studies obtained through a literature search that included data pertaining to suicide occurrence in affective illness into one of three groups: outpatients, inpatients, or suicidal inpatients. Suicide risks were calculated meta-analytically for these three groups, as well as for two previously published collections.

There was a hierarchy in suicide risk among patients with affective disorders. The estimate of the lifetime prevalence of suicide in those ever hospitalized for suicidality was 8.6%. For affective disorder patients hospitalized without specification of suicidality, the lifetime risk of suicide was 4.0%. The lifetime suicide prevalence for mixed inpatient/outpatient populations was 2.2%, and for the nonaffectively ill population, it was less than 0.5%.

The percentage of subjects dead due to suicide (case fatality prevalence) is a more appropriate estimate of suicide risk than the percentage of the dead who died by suicide (proportionate mortality prevalence). More important, it is well established that patients with affective disorders suffer a higher risk of suicide relative to the general population. However, no risk factor, including classification of diagnostic subtype, has been reliably shown to predict suicide. This article demonstrates a hierarchy of risk based on the intensity of the treatment setting. Given that patients with a hospitalization history, particularly when suicidal, have a much elevated suicide prevalence over both psychiatric outpatients and nonpatients, the clinical decision to hospitalize in and of itself appears to be a useful indicator of increased suicide risk.