Suicide mortality among patients treated for depression in an insured population

Studies of inpatient and specialty samples have estimated that 15% of depressed patients eventually die by suicide. This report examines suicide mortality among members of Group Health Cooperative of Puget Sound, a large health plan in western Washington state, who were treated for depression. Computerized discharge diagnoses, outpatient visit diagnoses, and outpatient prescription records were used to identify all enrollees who received treatment for depression during 1992, 1993, and 1994. Computerized death certificate data were used to identify all deaths and all suicide deaths in this sample before January 1, 1995. During the study period, 35,546 individuals received some treatment for depression and accounted for 62,159 person-years of follow-up. Of 850 deaths, 36 (4.2%) were classified as definite or possible suicides. Overall suicide mortality rate was 59 per 100,000 person-years, and was significantly higher among men than women (118 vs. 36 per 100,000 person-years, respectively). Risk per 100,000 person-years declined from 224 among patients who received any inpatient psychiatric treatment to 64 among those who received outpatient specialty mental health treatment to 43 among those treated with antidepressant medications in primary care to 0 among those treated in primary care without antidepressants. These data suggest that overall suicide risk among patients treated for depression is considerably lower than previous estimates based on specialty and inpatient samples. Risk is strongly related to treatment history--a likely indicator of illness severity.