Changes in Medical Interns’ Psychological Well-Being and Work Investment Perceptions During the Internship Year: An Interim Prospective Repeated-Measures Study at a Single Tertiary Medical Center

Background: Medical internship is a demanding transition into supervised clinical responsibility, but longitudinal evidence on interns’ well-being and work investment remains limited. Objective: To examine change across Q1–Q3 in self-reported well-being, work investment, and organizational perceptions. Methods: This prospective interim study included 126 questionnaires from 42 interns. The prespecified primary endpoint was change in general life satisfaction, assessed using the five-item Satisfaction With Life Scale (SWLS). Secondary repeated-measures outcomes were work satisfaction, work enjoyment, perceived stress, emotional and physical fatigue, weekly work hours, and perceived organizational culture. Repeated-measures ANOVA assessed omnibus time effects; linear contrasts were reported separately. Exploratory analyses used one mean score per intern. Results: Among 41 interns with complete SWLS scores across quarters, means were 4.36 ± 1.24, 4.56 ± 1.18, and 4.72 ± 1.04 on the 1–7 scale. The omnibus time effect did not reach statistical significance (F[2,80] = 3.005, p = 0.055, partial η2 = 0.070), although the linear contrast was nominally significant (p = 0.021); the Q3–Q1 difference was 0.36 points (95% CI 0.06–0.67). Weekly work hours increased from 58.98 ± 12.25 to 62.98 ± 11.82. Their omnibus effect was not significant (F[2,82] = 2.726, p = 0.071, partial η2 = 0.062), whereas the linear contrast was nominally significant (F[1,41] = 4.954, p = 0.032, partial η2 = 0.108). Other prespecified secondary omnibus tests were not significant. Internal consistency varied across measures and quarters. Exploratory participant-level comparisons indicated lower stress and physical fatigue among males and several inter-domain associations. Conclusions: No significant omnibus change was detected in the primary endpoint or the prespecified secondary outcomes. Nominal upward linear trends in life satisfaction and work hours warrant further investigation. Our findings should be regarded as preliminary and hypothesis-generating, rather than as evidence of sustained stability, resilience, or causal adaptation throughout internship.