The effects of desmopressin acetate (DDAVP), a vasopressin analog, were investigated using a computerized task designed to measure speed of accessing long-term memory at three levels of processing (physically identical decisions, same name decisions and same category decisions), and an unexpected free recall of the words presented. Forty-one healthy females and forty-three healthy males (age 18-34) intranasally received either 60 ug DDAVP in 0.6 ml of solution or 0.6 ml of saline 20 minutes prior to testing. DDAVP did not affect response time on the computerized task; however, when response time control trials were subtracted from the corresponding cells of the design, DDAVP was found to decrease response times for physically identical decisions only. In addition, DDAVP increased response times on the response time control task designed to measure the motor component of responding. Analysis of the error rates suggests a subtle sexually dimorphic effect of the peptide in that DDAVP facilitated accuracy for DDAVP-treated female subjects, but had an adverse effect in regard to error rates for DDAVP-treated male subjects. No treatment effect was found for incidental learning as measured by unexpected free recall of the words presented during the computer task
