07 Dec 1999

A study in this month's Neurology suggests that depression symptoms seen in early Alzheimer's are related to AD pathology, rather than being a response to memory loss and other Alzheimer's symptoms, or a risk factor that predisposes people to get Alzheimer's. The study, by Anna-Karin Berger, Lars Baeckman, and colleagues in Sweden, is the first prospective study of elderly people in the general population that has addressed this question.

The researchers studied 222 nondemented people over the age of 74 years, 34 of whom would be found to have Alzheimer's at a follow-up three years after the baseline interview. Those who later developed Alzheimer's were significantly more likely to have minor depressive symptoms at the baseline interview. These differences did not include symptoms related to "mood" (dysphoria, appetite disturbance, guilt, thoughts of death/suicide), but did include significant differences in the "motivation" constellation of depression symptoms, particularly in lack of interest, loss of energy, and concentration difficulties. The authors suggest that the presence of elevated motivational symptoms three years before diagnosis may reflect early changes in limbic or cortical brain areas needed for allocating and sustaining attention.—Hakon Heimer