The Interpersonal-Psychological Theory of Suicidal Behavior (IPTS) has yet to investigate the role of psychological pain in the development of suicide ideation. The current dissertation examined whether adding the construct of psychological pain to the IPTS can improve the theory’s utility in explaining suicide-related ideation. Participants: Participants included 266 young adults with epilepsy between the ages of 18 and 29 years (Mage = 24.07 years, SD = 2.12; 71.8% Male; 75.6% White) and 300 controls without epilepsy between the ages of 18 and 29 years (Mage = 24.78 years, SD = 2.98; 55% Female; 81.7% White). Design: The current study compared two models predicting suicide-related ideation using structural equation modeling. The first model was the desire for suicide component of the IPTS and the second model was similar to the IPTS but included the construct of psychological pain. The method of sampling employed was purposive criterion. All measures were completed by participants online via Qualtrics. Results: The majority of the measured factors fit the epilepsy group data poorly. All of the factors except for thwarted belongingness demonstrated adequate fit with control group data. Contrary to hypotheses, the two proposed models fit the control group data similarly; with the IPTS model being more parsimonious than the novel model. Perceived burdensomeness significantly predicted passive suicide ideation (IPTS 1) and psychological pain (novel model). A large amount of variance in suicide ideation was explained by state hopelessness (IPTS model) and psychological pain (novel model); however, contrary to hypotheses, state hopelessness did not partially mediate the relationship between psychological pain and suicide ideation in the novel model. Hopelessness was a nonsignificant predictor of suicide ideation when included in the novel model, with psychological pain explaining a large portion of the variance in hopelessness. Conclusion/Implications: The current study provides additional mixed evidence regarding the IPTS due to the poor fit of thwarted belongingness. The presence of burdensomeness, psychological pain, and hopelessness within the content of client statements may indicate the presence of passive or active thoughts of suicide. Future research focused on examining the models used in this study, or a respecification of the models, is needed on more acute samples that are clearly defined given the present conclusions were drawn from control group data.