Objective: This study investigated how factors of temperament and early maladaptive schemas predict psychiatric symptoms, as well as how they mediate the relation between early life stress and psychiatric symptoms in adults. Methods: A cross-sectional study was conducted with a sample of 200 university students. Data was collected through a sociodemographic questionnaire, the Adult Self-Report Inventory, the Childhood Trauma Questionnaire, the Young Schema Questionnaire, and the Temperament and Character Inventory-Revised. Results: A model including early maladaptive schemas, harm avoidance (temperament factor), and early life stress explained 69% of the variation of the psychiatric symptoms; among the predictors, early maladaptive schemas explained 31% of psychiatric symptoms, while harm avoidance explained 25%. Most of the predictive power associated with early life stress can be better explained by early maladaptive schemas and, to a lesser extent, harm avoidance. Conclusion: By managing these processes therapeutically, deleterious effects associated with early life stress can be minimized.