Subjective mild depressive symptoms are associated with abnormal diurnal cycle of salivary cortisol in older adults.

Background: Alterations in cortisol secretion pattern seem to be involved in the associations between aging, depression, and cognitive decline.

Objective: The aim of this study was to mainly assess cortisol circadian profile in older adults with subjective depressive symptoms.

Methods: Salivary cortisol samples from healthy young (n = 22) and old adults (n = 22), and from older adults who self-reported depressive symptoms in Geriatric Depression Scale (n = 22) were collected at 7 AM, 4 PM, and 10 PM and were analyzed by radioimmunoassay.

Results: Older adults with depressive symptoms presented the characteristic cortisol circadian pattern, but they showed higher cortisol levels at 10 PM than healthy young and elderly controls.

Conclusions: Our data suggest that mild depressive symptoms could be associated with a cortisol secretion pattern previously described as being predictive of cognitive decline.