Iranian Association for Intelligence and Talent Studies International Journal of Education and Cognitive Sciences 3041-8828 In Press 2027 05 01 Developing a Predictive Model of Psychosocial Adjustment to Illness Based on Health Locus of Control with the Mediating Role of Optimism in Patients with Systemic Lupus Erythematosus Developing a Predictive Model of Psychosocial Adjustment to Illness Based on Health Locus of Control with the Mediating Role of Optimism in Patients with Systemic Lupus Erythematosus 1 13 EN Journal Article 2026 05 11 <p><strong>Purpose: </strong>This study aimed to develop and test a structural model of psychosocial adjustment to illness based on health locus of control, with optimism as a mediating variable, among patients with systemic lupus erythematosus.</p> <p><strong>Methods and Materials:</strong> This descriptive-correlational study employed structural equation modeling. The statistical population comprised all female patients with systemic lupus erythematosus who attended Bouali, Farhikhtegan, and Amir Al-Momenin hospitals affiliated with Islamic Azad University in Tehran, as well as the Lupus Association, during the first six months of 2025. Based on the eligibility criteria, 280 patients were selected through purposive sampling. Data were collected using the Psychosocial Adjustment to Illness Scale developed by Derogatis (1986), the Life Orientation Test developed by Scheier and Carver (1985), and the Multidimensional Health Locus of Control Scale developed by Wallston et al. (1978). The data were analyzed using regression analysis and partial least squares structural equation modeling in SPSS and PLS software at a significance level of .05.</p> <p><strong>Findings:</strong> The overall goodness-of-fit index of the structural model was .341, indicating an acceptable predictive fit. The mean communality value was .399, and the mean coefficient of determination was .283, demonstrating that the exogenous variables in the model explained approximately 28% of the variance in psychosocial adjustment to illness. The structural analysis further indicated that optimism and pessimism significantly mediated the relationships of internal health locus of control and powerful-others health locus of control with psychosocial adjustment to illness. Accordingly, health-related control beliefs influenced patients’ psychosocial adjustment both directly and indirectly through motivational orientations toward positive and negative future outcomes.</p> <p><strong>Conclusion:</strong> Health locus of control and optimism are important psychological determinants of psychosocial adjustment to systemic lupus erythematosus. Patients who perceive greater personal control over their health and maintain more optimistic expectations may demonstrate better adjustment to the emotional, social, and functional demands of the disease. Therefore, psychological interventions designed to strengthen internal control beliefs, promote realistic optimism, and reduce pessimistic expectations may facilitate more effective adaptation to chronic illness among patients with systemic lupus erythematosus.</p> https://journalecs.com/index.php/ecs/article/download/439/368