Suicide is the 11th leading cause of death in the United States and accounts for approximately 30,000 deaths per year. Mood disorders, alcohol and substance abuse, male sex, and advancing age are associated with an increased risk for suicide. Older adults are more likely to attempt suicide with much higher lethality than younger patients; thus, the ratio of completed to attempted suicides increases with age. Older adults also tend not to discuss their suicide plans beforehand. There are unique stressors in this population, including retirement, loss of a loved one, social isolation, and an increasing burden of disability, which have been suggested as risk factors for suicide. Studies have examined the connection between suicide risk and medical illnesses, but most studies are from uncontrolled case series. Juurlink and associates evaluated the relationship between treatment of several illnesses and risk of suicide in older adults.

The trial design was a population-based case control study of patients at least 66 years of age who lived in a Canadian province. Patients in this group had universal access to health care, including drug coverage, physician services, and hospital care. Suspected suicides between January 1, 1992, and December 31, 2000, were identified and considered for the study group. The authors focused on 17 medical illnesses that are associated with suicide risk and matched a control group of patients who were similar in age, sex, and residential income quintile. The data from each group were analyzed to determine potential risk factors for suicide.

There were 1,354 incidents of suicide during the study. Firearms, hanging, and self-poisoning were the most common methods for suicide. Many of the 17 illnesses evaluated (see accompanying table) had an increased odds ratio (OR) for suicide, but the conditions with the highest OR were bipolar disorder (OR, 9.20), severe pain (OR, 7.52), depression (OR, 6.44), and psychosis and agitation (OR, 5.09). Patients with multiple illnesses had a higher risk for suicide than those who had no illnesses. Those who had seven or more of the 17 illnesses had about a ninefold higher risk of suicide than those who had no illnesses. Approximately one half of the patients who completed suicide had visited a physician within one week before the event.

The authors conclude that many of the common illnesses among older patients are independently associated with increased suicide risk. This finding is particularly true in older patients who have multiple illnesses. The authors add that this information can help physicians identify older adults who are at risk for suicide and open discussions with these patients to prevent suicide in this population.