Endogenous Cortisol Exposure and Declarative Verbal Memory: A Longitudinal Study of Healthy Older Adults

Objective Exposure to endogenous cortisol is associated with hippocampal degeneration and may contribute to problems with declarative memory, but effects of persistent versus phasic cortisol elevations have not been established. The present longitudinal investigation examined persistent individual differences and phasic changes in cortisol as they related to verbal memory, executive functions, and subjective cognitive function. Methods Older adults (n = 132, aged 60-93 years) were followed up for up to 5 years. They were assessed annually for verbal memory and every 6 months for executive functions, subjective cognitive function, and cortisol area under the curve (averaged over 3 days). Results In multilevel models, persistently but not phasically higher cortisol was associated with worse verbal memory in both learning (t(181) = 2.99, p = .003) and recall (t(280) = 3.10, p = .002). This effect withstood adjustment for stress, depression, metabolic health, and age. There was evidence for attenuated primacy in learning with higher persistent cortisol. Phasic increases in cortisol were not associated with changes in memory, and cortisol was not related to executive functions or subjective cognitive function. Conclusions Higher secretion of cortisol may, over time, contribute to memory dysfunction in older adults.