The Douglas Hospital Longitudinal Study of Normal and Pathological Aging: summary of findings

In 1988, our group initiated the Douglas Hospital Longitudinal Study of Normal and Pathological Aging to assess the association between secretion of the stress hormone cortisol and cognitive performance in a group of 51 older adults. In this paper, we summarize the data obtained in this study to date. We have found that long-term exposure to high endogenous levels of cortisol is associated with both memory impairments and a 14; smaller volume of the hippocampus. We also report on studies showing that in older adults with moderate levels of cortisol over time, memory performance can be acutely modulated by pharmacologic manipulations of cortisol. We describe one participant who was included in the group of older adults presenting with increased cortisol levels over time, memory impairments and reduced hippocampal volume and in whom major depression, followed by Alzheimer's disease, developed during the course of the study. Together, the results of the Douglas Hospital Longitudinal Study of Normal and Pathological Aging show that increased secretion of cortisol in the older human population is significantly associated with impairment of cognitive function during aging.