The interplay between Post Traumatic Stress Disorder (PTSD) and self-efficacy lies in the efficacy-activated processes that comprise an individual’s cognitive and belief systems. Previous research shows that low self-efficacy contributes to development and maintenance of mental disorders like PTSD, while high self-efficacy influences ability to visualize, implement, and maintain success scenarios (resilience) related to effective mental coping. Negative cognition makes it difficult to pursue a coping success scenario in the presence of overriding self-doubt and often arises because a traumatic event has made it difficult to retrieve positive self-identities or has reactivated negative self-identities. Consistent with this model, we predict that a negative association exists between self-efficacy and PTSD onset susceptibility. We employed a pre-test/post-test design using a susceptibility/resilience questionnaire to assess predisposition to PTSD. Vignettes, designed to either raise or lower self-efficacy, were used to separate participants into groups and revealed a significant interaction between low and high self-efficacy across the pre- and post-tests, supporting the assertion that high self-efficacy guards against PTSD onset susceptibility while low self-efficacy may make someone more susceptible to developing PTSD-related symptoms.