Inverted-U function between salivary cortisol and retrieval of verbal memory after hydrocortisone treatment

The present study investigated the effect of a single oral dose of hydrocortisone (cortisol) on retrieval of verbal and nonverbal declarative memory. Fifty-nine healthy participants were randomly assigned to either receive 25 mg cortisol or a placebo 45 min before retrieval in a standardized memory test procedure. There was no global effect of cortisol on either verbal or nonverbal memory. However, a specific negative effect on free recall of associative verbal material appeared. In addition, high responders (salivary cortisol concentration > 68.25 nmol/L) exhibited impaired verbal memory compared with low responders (< 68.25 nmol/L). The results suggest specific nonlinear effects of cortisol on declarative memory retrieval, which appear to be more pronounced for verbal material.