Role of Oxytocin

Background: Social exclusion is a robust correlate of suicidal ideation and behavior. However, there is little research examining the biological factors contributing to the link between social exclusion and suicide risk. Prior research has indicated that oxytocin, an important modulating neuropeptide in the regulation of social interactions, protects against the negative effects of social exclusion by motivating social behavior in excluded individuals. In non-psychiatric controls, oxytocin levels and desires to affiliate with others increase in response to feelings of loneliness and social exclusion; however, in individuals with psychiatric disorders that are associated with serious suicide-related symptoms, oxytocin levels decrease in response to social exclusion. This suggests that dysregulated oxytocin functioning may be a correlate of suicidal behavior among socially excluded, at-risk individuals. However, crucially, no studies have examined this potential association. Aims: This study examined whether individuals with and without a history of suicide attempts differ in their oxytocin levels and desires to affiliate with others at baseline and following social exclusion. Methods: Young adults (N = 100) with and without prior attempts completed Cyberball, a computerized, social exclusion paradigm. Prior to and approximately 10 minutes after Cyberball, blood samples and levels of self-reported desires to affiliate with others, thwarted belongingness and perceived burdensomeness were obtained. Data were analyzed using one-way MANOVAs and two-way mixed design ANCOVAs. Results: No group differences emerged at baseline. Although no main effects emerged, a significant group by time interaction effect emerged such that among suicide attempters, desires to affiliate and oxytocin levels significantly decreased following social exclusion. Among depressed and healthy controls, desires to affiliate and oxytocin levels increased following exclusion. There were no significant changes in thwarted belongingness and perceived burdensomeness across groups following exclusion. Conclusions: Overall, our findings suggest that dysregulated oxytocin levels in response to social exclusion may be a correlate of suicide risk.