Antidepressants are frequently initiated in persons with Alzheimer's disease already before the diagnosis, shows a recent study from the University of Eastern Finland. Among persons with Alzheimer's disease, the initiation of antidepressant use was most common during the six months after the Alzheimer's diagnosis, and more frequent than among comparison persons without Alzheimer's disease even 4 years after the diagnosis. The results were published in International Journal of Geriatric Psychiatry.

Antidepressant initiation was more frequent among persons with Alzheimer's disease already 9 years before the diagnosis than among comparison persons not diagnosed with Alzheimer's disease. This finding was somewhat surprising. It may be related to more frequent treatment of depressive symptoms because depression has been associated with an increased risk of Alzheimer's disease in previous studies.

Antidepressant use was investigated in the Finnish nationwide MEDALZ study from 9 years before until 4 years after the diagnosis of Alzheimer's disease. The difference in antidepressant initiations persisted during the entire follow-up period. During the 13-year follow-up period, 42% of persons with Alzheimer's disease and 22% of persons not diagnosed with the disease initiated antidepressant use. The most commonly used antidepressant group was selective serotonin reuptake inhibitor (SSRI) drugs, followed by mirtazapine.

The register-based study was based on 62,104 Finnish persons with Alzheimer's disease diagnosed between 2005 and 2011.