Stress-induced cortisol elevations are associated with impaired delayed, but not immediate recall

Glucocorticoids are known to modulate memory functions, with elevated cortisol levels being associated with impaired declarative memory. This specific effect has been shown in several studies using pharmacological doses of cortisol. The present study was designed to assess the effects of stress-induced cortisol elevations on (1) the type of memory processing (encoding, consolidation and retrieval), and (2) on the emotional valence of the material under study. Sixteen healthy females were presented neutral and emotional material (words and paragraphs) before and after a stress challenge. Declarative memory was tested immediately after presentation and 24 h later (delayed recall). Delayed, but not immediate recall of the information presented after the stress challenge was significantly reduced compared with delayed recall of information presented before the stress challenge. In line with this, strong negative correlations were found for delayed recall of words and spatial memory presented after the challenge with post-stress cortisol levels, whereas no significant correlations were found between cortisol levels and delayed recall at day 1. These results suggest that stress-induced cortisol specifically affects long-term consolidation of declarative memories. These findings may have implications for understanding the effects of traumatic stress on memory functioning in patients with stress-related psychiatric disorders.