Abstract
BACKGROUND: Changes in academic structure—such as the implementation of a trimester system—can impose considerable psychological strain on students. In nursing education, such reforms may elevate stress, anxiety, and depression while undermining self-efficacy. Academic advising can potentially buffer these effects, yet its role during transitional periods remains underexplored in the Saudi context. PURPOSE: This study investigates the levels of stress, anxiety, depression, and self-efficacy among nursing students following the adoption of a trimester academic system at King Saud bin Abdulaziz University for Health Sciences (KSAU-HS) while examining the mediating role of academic advising in this context. METHODS: A mixed-methods design was employed. The quantitative phase included a convenience sample of 465 nursing students at KSAU-HS, who completed reliable and validated measures of the Depression, Anxiety, and Stress Scale (DASS-21), the General Self-Efficacy Scale, and a researcher-developed Academic Advising Scale. In the qualitative phase, six focus group interviews were conducted with a purposive sample of 30 students until data saturation to gather in-depth insights into students’ emotional experiences during the implementation of the trimester system. Quantitative data were analyzed through inferential statistics and path analysis. Qualitative data were examined via conventional content analysis. RESULTS: Students reported moderate levels of psychological distress, with mean total DASS-21 score of 47.56 ± 28.95, including stress (17.29 ± 10.14), anxiety (15.20 ± 10.29), and depression (15.07 ± 11.5). Self-efficacy was moderately high (M = 30.92 ± 4.45), while academic advising satisfaction showed moderate variability (M = 30.06 ± 10.10). Significant negative correlations were found between psychological distress and self-efficacy (r = − 0.417, p < 0.01). Structural equation modeling confirmed that academic advising significantly mediated the relationship between psychological distress and self-efficacy (indirect effect β = 0.08, p = 0.02). Qualitative findings supported these results through themes of emotional turbulence, self-efficacy under pressure, advising gaps, and student-centered support. CONCLUSION: Academic reform contributes to elevated psychological distress among nursing students, though academic advising is a mediating resource in preserving students’ self-efficacy. Enhancing advising systems, training faculty in student-centered support, and involving students in academic reforms are critical to promoting psychological resilience in nursing education. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12909-025-08229-w.