Behavioral effects of neurohypophyseal peptides in healthy volunteers: 10 years of research.

A short summary of behavioral studies on the effects of vasopressin and oxytocin published during the past decade is provided. Only studies using healthy volunteers as subjects were included. Among the studies reviewed, large differences exist with respect to design, procedure, treatment schedule and dose used. Results from the majority of the studies support that vasopressin and oxytocin affect central nervous functions in man after systemic administration. Since the hormonal influences do not appear to be consistently restricted to certain stages of stimulus processing but nonspecifically concern a great variety of cognitive functions, it is suggested that the influence of hypophyseal peptides on stimulus processing is mediated through an action on basic mechanisms involved in the general regulation of central nervous activation, i.e., on arousal systems that could also alter affective aspects of stimulus processing. The altogether moderate number of studies, so far, does not provide a sufficient data base justifying a clinical application of these peptides as nootropic treatments.