Long-term effects of antidepressants on cognition in patients with Alzheimer's disease

Purpose: Approximately 25-40% of patients with Alzheimer's disease (AD) may develop depression. Antidepressants are typically used to treat depression in this population. However, their effect on cognition has been rarely studied and the results are conflicting. In addition, the long-term effects of antidepressants on cognition have not been studied. Therefore, the objective of the study was to evaluate the effects on cognition in patients with AD treated with antidepressants for at least 9 months. Methods: Data on antidepressant use over a minimum period of 9 months were retrospectively collected for patients with AD receiving cholinesterase inhibitors. Data on cognition were analyzed to compare those taking antidepressant therapy and those not receiving antidepressants. Results: Ninety-nine of 210 patients met our inclusion criteria. Fifty-eight patients were prescribed an antidepressant (e.g. selective serotonin reuptake inhibitors (SSRIs), newer generation antidepressants). Sertraline (mean dose: 82 mg/day) and citalopram (mean dose: 35 mg/day) were the most commonly prescribed antidepressants. The baseline mean Mini Mental State Examination (MMSE) score was 16.32 with an average annual rate of cognitive decline of 2.55 for patients receiving antidepressants compared with 16.59 (P = NS) and 2.27 (P = NS) for those not taking antidepressants. Conclusions: Our small sample data indicate no differences in baseline MMSE scores and cognitive decline between the two groups, suggesting antidepressants did not contribute significantly to cognitive decline over a utilization period of at least 9 months.