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.

Reference:Berger AK, Fratiglioni L, Forsell Y, Winblad B, Backman L. The occurrence of depressive symptoms in the preclinical phase of AD: a population-based study. Neurology 1999 Dec;53:1998-2002. Abstract