Medical illness and the risk of suicide in the elderly

Suicide is a leading cause of death, and rates are especially high among the elderly. Medical illnesses may predispose to suicide, but few controlled studies have examined the association between specific diseases and suicide. We explored the relationship between treatment for several illnesses and the risk of suicide in elderly patients using a population-based approach.

All Ontario residents 66 years or older who committed suicide between January 1, 1992, and December 31, 2000, were identified from provincial coroners' records. Their prescription records during the preceding 6 months were compared with those of living matched controls (1:4) to determine the presence or absence of 17 illnesses potentially associated with suicide.

During the 9-year study period, we identified 1354 elderly patients who died of suicide. The most common mechanisms involved firearms (28%), hanging (24%), and self-poisoning (21%). Specific illnesses associated with suicide included congestive heart failure (odds ratio [OR], 1.73; 95% confidence interval [CI], 1.33-2.24), chronic obstructive lung disease (OR, 1.62; 95% CI, 1.37-1.92), seizure disorder (OR, 2.95; 95% CI, 1.89-4.61), urinary incontinence (OR, 2.02; 95% CI, 1.29-3.17), anxiety disorders (OR, 4.65; 95% CI, 4.07-5.32), depression (OR, 6.44; 95% CI, 5.45-7.61), psychotic disorders (OR, 5.09; 95% CI, 3.94-6.59), bipolar disorder (OR, 9.20, 95% CI, 4.38-19.33), moderate pain (OR, 1.91; 95% CI, 1.66-2.20), and severe pain (OR, 7.52; 95% CI, 4.93-11.46). Treatment for multiple illnesses was strongly related to a higher risk of suicide. Almost half the patients who committed suicide had visited a physician in the preceding week.

Many common illnesses are independently associated with an increased risk of suicide in the elderly. The risk is greatly increased among patients with multiple illnesses. These data may help clinicians to identify elderly patients at risk of suicide and open avenues for prevention.