BACKGROUND: This study examined psychological reactions to perceived threats, viewed within the context of human evolutionary history. We compared the relative weight of perceived threat to life or physical harm versus social threat, i.e., humiliation and/or rejection, in symptoms of posttraumatic stress disorder (PTSD) and social anxiety disorder (SAD). METHODS: Participants were 50 women with clinically significant posttraumatic stress symptoms (PTSS) and 59 women with little or no PTSS (control group) selected from a large, population-based cohort of women in Iceland, the SAGA Cohort. Participants rated (1) life threat, (2) physical threat, (3) humiliation, and (4) rejection during their worst trauma or stressor. RESULTS: Rates of both life and social threats were higher in the PTSS than control group. Among the PTSS participants, 4 % (n = 2) reported primarily life threats (vs. 6.8 %, n = 4 in controls), 36 % (n = 18) reported primarily social threats (vs. 33.9 %, n = 20 in controls), and 60 % (n = 30) reported both types of threats (vs. 15.3 %, n = 9 in controls). Those who reported dual life and social threats exhibited elevated PTSS compared to those who experienced a single type of threat. The highest levels of life or physical threat, along with humiliation, predicted PTSS severity, but rejection did not. Nearly half of the PTSS group (approximately 50 %, n = 25) also met criteria for SAD compared to roughly 14 % (n = 8) in the control group, and humiliation predicted SAD symptom severity. Notably, 18 % of the PTSS group (n = 9) linked the onset of their SAD and PTSS to a singular trauma or stressor involving a social threat. CONCLUSIONS: The findings underscore the role of social threat in PTSD and SAD, with implications for theoretical models of both disorders.