Depressive symptoms may indicate Alzheimer's risk

People who are frequently diagnosed with depression may run higher risk of having Alzheimer's disease later as researcher have found that use of antidepressants is more common among people who go on to develop the most common form of dementia.

Antidepressants are frequently initiated in persons with Alzheimer's disease (AD) already before the diagnosis, the findings showed.

"The incidence of antidepressant use was higher in persons with AD than in comparison persons, and it was not explained by history of hospital-treated psychiatric disorders," the researchers said.

The findings by the researchers from University of Eastern Finland was based on 62,104 Finnish persons with Alzheimer's disease diagnosed between 2005 and 2011.

The results were published in International Journal of Geriatric Psychiatry.

The researchers found that antidepressant initiation was more frequent among people with Alzheimer's disease already nine 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 study from nine years before to four 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 percent of persons with Alzheimer's disease and 22 percent 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.

"Widespread use of antidepressants in persons with AD is concerning as their efficacy is controversial and their use is associated with adverse events," the study noted.