Background/Objectives: Medical students experience significant mental stress during clinical internships. This study aimed to assess the levels of uncertainty stress among medical interns, evaluate its temporal changes and associations with doctor–patient conflict and reference norm, and provide insights for stress-alleviating policies and educational initiatives. Methods: A prospective longitudinal panel study was conducted; 131 medical students preparing for clinical internships were recruited via WeChat social media groups from June 2023 to June 2024. Data were collected at three time points using an online survey on Wenjuanxing: before the internship, three months into the internship, and after the internship. Variables such as uncertainty stress, doctor–patient conflict, and reference norm were measured, and data were analyzed using GEE and the GLMM program. Results: A total of 122 students completed all three waves of the study. Uncertainty stress decreased over the internship period (W = 7.25, p < 0.05), while doctor–patient conflict increased (W = 6.65, p < 0.05). Uncertainty stress was positively associated with the reference norm from teachers (β = 0.856, p < 0.05) and doctor–patient conflict (β = 1.068, p < 0.05). Conclusions: Although uncertainty stress reduces as internships progress, doctor–patient conflict rises. A supportive learning environment, especially from teachers, is crucial for mitigating stress. Medical schools and hospitals should implement comprehensive strategies to address individual stressors and institutional factors, considering the associations between uncertainty stress, doctor–patient conflict, and reference norm. However, the study has limitations such as a small sample size and reliance on self-reported measures, indicating a need for further research.

Background/Objectives: Medical students experience significant mental stress during clinical internships. This study aimed to assess the levels of uncertainty stress among medical interns, evaluate its temporal changes and associations with doctor - patient conflict and views of relevant reference populations, and provide insights for stress - alleviating policies and educational initiatives. Methods: A prospective longitudinal panel study was conducted. 131 medical students preparing for clinical internships were recruited via WeChat social media groups from June 2023 to June 2024. Data were collected at three time points: before internship, three months into the internship, and after the internship using an online survey on Wenjuanxing. Variables such as uncertainty stress, doctor - patient conflict, and reference population opinions were measured, and data were analyzed using repeated measures ANOVA and the GIM program. Results: A total of 122 students completed all three waves of the study. Uncertainty stress decreased over the internship period (β = 4.14, p < 0.05), while doctor - patient conflict increased (β = 76.26, p < 0.05). Uncertainty stress was positively associated with doctor - patient conflict from teachers and the reference population from teachers, and negatively associated with doctor - patient conflict. Conclusions: Although uncertainty stress reduces as internships progress, doctor - patient conflict rises. A supportive learning environment, especially from teachers, is crucial for mitigating stress. Medical schools and hospitals should implement comprehensive strategies to address individual stressors and institutional factors, considering the associations between uncertainty stress, doctor - patient conflict, and reference populations. However, the study has limitations such as a small sample size and reliance on self - reported measures, indicating a need for further research.