Oxytocin facilitates the sensation of social stress

Abstract

Essentially all social species experience social stress which can be a catalyst for detriments in mental and physical health. The neuropeptide oxytocin (OXT) has been shown to produce anxiolytic and antistress effects, thereby qualifying the OXT system as a promising drug target in the treatment of stress-related disorders. However, recently it has been shown that OXT can have anxiogenic effects as well. In the present study, we used functional magnetic resonance imaging to scan the brains of 60 healthy men while they were exposed to social stress after they received either intranasal OXT (24 IU) or placebo treatment. Although OXT administration did not alter salivary cortisol levels as a surrogate marker of stress axis activity, our participants initially reported an increment in perceived social stress. This behavioral effect was paralleled on the neural level by increased activity in the precuneus and cingulate cortex. Taken together, our results support the hypothesis that OXT can induce a self-referential processing bias which facilitates the sensation of social stress in the absence of altered endocrine responses.

Keywords: fMRI; oxytocin; social; stress.

Figure 1

Displayed are verbal ratings of and salivary cortisol responses to social stress. In the first block of the stress task ratings of the stress condition, compared to the nonstress condition, were significantly higher under oxytocin (OXT) than under placebo. Elevated cortisol levels demonstrated that the task was successful in inducing an endocrine stress response; however, OXT had no modulatory effect on cortisol levels.

Figure 2

Illustrated are OXT effects on the neural correlates of psychosocial stress. (a) OXT specifically enhanced stress‐related activation in the posterior cingulate cortex, precuneus, and also in a region of interest, the anterior cingulate cortex. (b) Parameter estimates of the peak activations for the stress and nonstress condition confirm the observed response changes under OXT. Error bars indicate the standard error of the mean (SEM). Abbreviations: L, left; R, right; **P < 0.01.