Immediate and prolonged effects of cortisol, but not propranolol, on memory retrieval in healthy young men.

BACKGROUND While acute cortisol administration has been found to impair retrieval of emotional memories in healthy subjects, the duration of this memory impairment is still unknown. Propranolol, on the other hand, may impair the reconsolidation of emotional memories during reactivation, although human studies examining such effects are scarce. The present investigation was therefore undertaken to examine the immediate and prolonged effects of a single administered dose of cortisol or propranolol on memory retrieval in a double-blind placebo controlled design. METHODS Eighty-five healthy male participants were asked to retrieve previously learned emotional and neutral information after ingestion of 35 mg cortisol, 80 mg propranolol or placebo. After a washout period of 1 week, recall was again tested. RESULTS Memory retrieval of neutral and emotional information was impaired by a single dose of cortisol compared to placebo. The memory impairment due to cortisol remained, even after a washout period of 1 week. No immediate or prolonged effects of propranolol on memory retrieval were found, despite significant reductions in sympathetic arousal. CONCLUSIONS These results lend support to the hypothesis that cortisol is able to attenuate (emotional) memory recall in men over longer time spans and may therefore augment the treatment of disorders like post-traumatic stress disorder and phobias, but do not clarify the mechanism(s) through which propranolol exerts its therapeutic effects.