Abstract
BACKGROUND: Psychological security, defined as an individual's sense of safety, stability, and freedom from threat, is a fundamental aspect of mental health, especially for medical students experiencing high academic stress. While childhood trauma is known to undermine psychological security, its mechanisms remain underexplored in non-Western contexts. This study tested whether self-disclosure and perceived social support mediate this relationship in Iranian medical students. METHODS: This cross-sectional correlational study (March 2023-January 2024) was conducted on 414 medical students (248 females, 166 males) recruited through stratified random sampling at Mashhad University of Medical Sciences. The study population included undergraduate medical students (semesters 1-14). Validated Persian versions of the Childhood Trauma Questionnaire, the Psychological Security Questionnaire-Short Form, the Multidimensional Scale of Perceived Social Support, and the Chelune Self-Disclosure Scale were administered in a 25-minute session. Data were analyzed using SPSS v26 and SmartPLS 3.3.9 (PLS-SEM) to test mediation effects, considering the non-normal distribution of variables. RESULTS: There was a moderate negative correlation between childhood trauma and psychological security (β = - 0.368, 95% CI [-0.42, - 0.31], f² = 0.15, p < .001). Self-disclosure (β = - 0.234, CI [-0.29, - 0.18]) and perceived social support (β = 0.213, CI [0.16, 0.27]) mediated 27.7% and 24.4% of the total relationship between childhood trauma and psychological security, respectively. The model explained 48.1% of variance and demonstrated good fit (SRMR = 0.062). CONCLUSION: Childhood trauma erodes psychological security in medical students through impaired self-disclosure and social support. Recommended interventions include trauma-informed faculty training, anonymous peer support platforms, and regular mental health screening.