The Mediating Role of Psychological Capital in the Relationship Between Childhood Trauma and Mobile Phone Addiction Among Chinese Nursing Students: A Cross-Sectional Questionnaire Survey

Background: Nursing students, as future clinical professionals, face an increasing risk of mobile phone addiction (MPA), which can compromise their academic performance, mental health, and clinical competence. Therefore, understanding the prevalence and underlying mechanisms of MPA is crucial for protecting mental health, promoting academic success, and strengthening professional development in this population. This study examined the relationship between childhood trauma and MPA and evaluated the mediating role of psychological capital, offering a theoretical foundation for improving mental health and fostering healthy smartphone use among nursing students. Methods: This cross-sectional, descriptive, correlational study was conducted between November 2023 and April 2024. An online survey was administered to 1249 undergraduate nursing students (majority female). Standardized instruments, including the Childhood Trauma Questionnaire, the Psychological Capital Questionnaire, and the Mobile Phone Addiction Tendency Scale, were used to assess childhood trauma, psychological capital, and MPA, respectively. Data analysis comprised multiple statistical approaches, including descriptive statistics, testing for common method bias, independent-sample t-tests, one-way analysis of variance (ANOVA), and Pearson correlation analyses. Mediation analysis was performed using Hayes’ PROCESS macro (Model 4) with bootstrap resampling (5000 iterations) to generate bias-corrected confidence intervals, thereby strengthening the robustness of the mediation estimates. Results: Among the 1249 nursing students, 456 (36.5%) exhibited MPA symptoms. Correlation analyses revealed that MPA was positively correlated with childhood trauma (r = 0.237, p < 0.001) and negatively associated with psychological capital (r = −0.298, p < 0.001). Additionally, childhood trauma was negatively associated with psychological capital (r = −0.276, p < 0.001). Mediation analysis demonstrated that psychological capital partially mediated the association between childhood trauma and MPA. The total effect of childhood trauma on MPA was 0.245, consisting of an indirect effect of 0.072 (29.4%) and a direct effect of 0.173 (70.6%). Conclusions: These findings demonstrate that MPA is highly prevalent among nursing students, that childhood trauma positively predicts MPA, and that psychological capital partially mediates this association. These findings suggest that strengthening psychological capital may attenuate the adverse effects of childhood trauma on MPA, thereby supporting learning efficiency, protecting mental health, and promoting professional development among nursing students.