Symptoms of depression in older persons appear to be linked to a higher risk of Alzheimer's disease, according to researchers at Rush-Presbyterian-St. Luke’s Medical Center in Chicago.

The researchers said more than 650 members of the Catholic clergy aged 65 years and older who participated in the study had an average of one depressive symptom at the outset.

Over the course of seven years, 108 participants developed Alzheimers, with the risk of developing the disease rising by 19 percent with each new depressive symptom, such as feelings of loneliness or difficulty sleeping, the researchers reported in the journal Neurology.

"The results raise the possibility that depressive symptoms in older persons may be associated with risk of developing Alzheimer's disease," the researchers concluded.

Other sources: Neurology