The influence of social factors on the response to stress.

The studies described in this paper provide evidence for the importance of social factors in determining the response of the hypothalamic-pituitary-adrenal (H-P-A) system to stress. The presence of familiar social partners can reduce or eliminate the cortisol response to either loss of a significant social relationship or to fear inducing stimulus. In contrast, disruptions of ongoing social behavior can be a potent activator of the H-P-A axis. Social isolation, the formation of new social groups of unfamiliar monkeys, and disruption of social behavior under conditions of high demand food seeking, all result in elevations of circulating cortisol. Of importance is that these elevation persist for protracted periods of time and represents an animal model of chronic stress.