Age-Related response to redeemed antidepressants measured by completed suicide in older adults: A nationwide cohort study

Objective: To examine if the suicide rate of older adults prescribed antidepressants varies with age and to assess the proportion of older adults who died by suicide that had recently been prescribed antidepressants. Methods: A population-based cohort study using a nationwide linkage of individual-level records was conducted on all persons aged 50 living in Denmark during 1996-2006 (1,215,524 men and 1,343,568 women). Suicide rates by treatment status were calculated using data on all antidepressant prescriptions redeemed at pharmacies. Results: Individual-level data covered 9,354,620 and 10,720,639 person-years for men and women, respectively. Men aged 50-59 who received antidepressants had a mean suicide rate of 185 (95% confidence interval [CI]: 160-211) per 100,000, whereas for those aged 80 the rate was 119 (95% CI: 91-146). For women, the corresponding values were 82 (95% CI: 70-94) and 28 (95% CI: 20-35). Logistic regression showed a 2% and 3% decline in the rate for men and women, respectively, considered in treatment with antidepressants, with each additional year of age. An opposite trend was found for persons not in treatment. Fewer persons aged 80 dying by suicide had received antidepressant prescriptions during the last months of life than younger persons. Conclusion: An age-dependent decline in suicide rate for antidepressant recipients was identified. One reason could be that older adults respond better to antidepressants than younger age groups. Still, the increasing gap with age between estimated prevalence of depression and antidepressant prescription rate in persons dying by suicide underscores the need for assessment of depression in the oldest old.