The influence of testosterone on rejection sensitivity: Insights from salivary testosterone levels and genetic polymorphisms

Rejection sensitivity is invovled in a defensive mechanism that triggers an individual's flight or fight response to social exclusion. Inspired by the roles of testosterone in defensive behaviors, we explored the relationships between three indicators of testosterone and rejection sensitivity through two studies. In Study 1, we recruited a cohort ( N = 183, 88 females) and assessed individuals’ rejection sensitivity, salivary testosterone levels, and the ratio of the relative lengths of the second to fourth fingers (2D:4D), aiming to investigate the relationships between these testosterone indicators and rejection sensitivity. Study 2 involved a larger sample ( N = 1112, 677 females), where we genotyped testosterone genetic polymorphisms and evaluated individuals’ rejection sensitivity to determine the associations between these polymorphisms and rejection sensitivity. Study 1 showed that testosterone levels were associated with rejection sensitivity among females, with higher testosterone levels correlating with lower rejection sensitivity. By contrast, this study did not find a significant association between the 2D:4D ratio and rejection sensitivity. Moreover, Study 2 indicated that females with the CC genotype of SRD5A2 rs523349 or the LL of AR(CAG)n exhibited reduced rejection sensitivity. Collectively, these findings underscore the impact of testosterone levels and genetic polymorphisms on rejection sensitivity.