[Bidirectional longitudinal associations of perceived stress with anxiety and depressive symptoms among medical students: A three

objectivesPerceived stress, anxiety symptoms, and depressive symptoms may co-occur among medical students, but their temporal ordering and bidirectional longitudinal relationships remain unclear. Whether conventional cross-lagged panel model (CLPM) adequately reflect within-person dynamic changes also requires examination through sensitivity analyses. This study aims to examine changes in perceived stress, anxiety symptoms, and depressive symptoms across 3 assessments among medical students and to investigate the bidirectional longitudinal associations among these 3 variables.

methodsA three-wave longitudinal design was used. Medical students were surveyed in June, September, and December 2025, with valid sample sizes of 376, 361, and 343 at T1, T2, and T3, respectively. Perceived stress, anxiety symptoms, and depressive symptoms were assessed using the Chinese Perceived Stress Scale (CPSS), the Generalized Anxiety Disorder Scale-7 (GAD-7), and the Patient Health Questionnaire-9 (PHQ-9), respectively. Linear mixed models were used to examine changes in the main variables across the 3 time points, with Bonferroni correction for pairwise comparisons. Pearson correlation analysis was used to examine correlations among variables. The primary analysis used a three-variable CLPM, in which CPSS, GAD-7, and PHQ-9 were simultaneously included to examine bidirectional longitudinal statistical associations among perceived stress, anxiety symptoms, and depressive symptoms. Based on the primary three-variable CLPM, two-variable CLPMs for CPSS-GAD-7 and CPSS-PHQ-9 were additionally fitted as supplementary analyses to examine the longitudinal associations of perceived stress with anxiety and depressive symptoms separately. Random-intercept cross-lagged panel models (RI-CLPMs) were further fitted as sensitivity analyses to examine the interpretive boundaries of the conventional CLPM findings after distinguishing stable between-person differences from within-person dynamic changes. All longitudinal models were adjusted for sex and age, and parameters were estimated using robust maximum likelihood estimation.

resultsAll 3 measures showed significant time effects, with scores being highest at T2, followed by T3 and T1 (all

conclusionsPerceived stress, anxiety symptoms, and depressive symptoms showed longitudinal associations among medical students. The three-variable CLPM indicated that, after accounting for the interrelations between anxiety and depressive symptoms, perceived stress remained prospectively associated with subsequent anxiety and depressive symptoms, and anxiety and depressive symptoms also showed bidirectional longitudinal associations. RI-CLPM sensitivity analyses suggested that these findings should be interpreted primarily as longitudinal statistical associations within the conventional CLPM framework rather than as evidence of clear within-person causal effects; in particular, the within-person dynamic relationship between perceived stress and depressive symptoms requires further validation.