Post-dexamethasone cortisol level and memory performance in elderly depressed patients

Depressed patients frequently show non-suppression in the dexamethasone suppression test, i.e. elevated post-dexamethasone cortisol levels. Elevated cortisol levels have been suggested to cause memory impairment through toxic effects on hippocampal neurons. In order to test this hypothesis, we studied the relationships between post-dexamethasone cortisol level and memory impairment in a group of 27 elderly depressive patients. In contrary to the expected, we found a positive correlation between post-dexamethasone cortisol level and memory performance. Thus, a dose-effect relationship between cortisol and memory impairment could not be ascertained. In some patients in early stages of Alzheimer's disease, cortisol may even have protective effects on memory performance through its anti-inflammatory action.