Full Text: A long-term study of people over age 65 years suggests that severity of depressive symptoms is related to risk for Alzheimer's disease, according to an article in the August 13th issue of Neurology.

More than 650 elderly people took part in the seven-year study, which included annual neurological evaluations and testing of cognitive function. Baseline testing showed about half of the participants had no depressive symptoms and the remainder had from one to eight symptoms. Only one percent of participants had symptoms severe enough to warrant a diagnosis of major depression.

During annual follow-ups, 108 of 650 participants developed Alzheimer's disease. Those with the greatest number of depressive symptoms at the start of the study were more likely to develop Alzheimer's disease and also showed more rapid cognitive decline.

"According to our results, the people with the largest number of depressive symptoms also had the greatest risk of developing Alzheimer's disease," said lead author Robert S. Wilson, Ph.D. "With each additional symptom, the risk of Alzheimer's disease increased by about 20 percent."

The American study participants were drawn from the Religious Orders Study, an ongoing examination of aging and Alzheimer's disease in older Roman Catholic nuns, priests, and brothers who have agreed to annual evaluations and brain donation at death. Participants were all over age 65 years and did not have dementia at the time of enrollment.

"We are grateful for the remarkable dedication and altruism of this unique group of people," said Wilson.