Correlation between anxiety and serum prolactin in humans.

The organised social structure of primate species largely determines individual behaviour. Moreover Keverne et al. in Advanced Views in Primate Biology, Springer, Berlin (1982) [1] have demonstrated that social interaction among confined male talapoin monkeys may result in endocrine changes, and that these in turn may modify behaviour. We have undertaken a study to determine whether similar endocrine changes can be induced in confined human volunteers. Five men were confined on a boat for fourteen days. Repeated plasma samples were taken under controlled conditions for assay of testosterone, prolactin and cortisol. After each sample the men completed a questionnaire to document self-perceived anxiety. The men were also secretly ranked for dominant/aggressive behaviour towards the other males. Significant correlation was found between day-to-day changes in anxiety and stress hormones, cortisol and prolactin. Significant correlation was found also between plasma prolactin, testosterone and rank position for dominance/aggression. It is concluded that under some circumstances social interaction may modify endocrine status in humans.